Glossary

TermDefinition
4WDA vehicle with four-wheel drive has a drive train that can send power to all four wheels. This system locks the front and rear axles together to provide additional traction when there is not enough friction on the road. It also provides additional traction, especially when transporting heavyweight loads up a steep incline. To simply put, when one tire loses traction, the other continues to spin, propelling your vehicle forward.

But the four-wheel-drive system is not intended to be used regularly. It is only applicable to particular types of roads and is dependent on driving conditions. Some vehicles come equipped with a four-wheel-drive system that automatically engages when its sensor detects a change in the wheel’s rotational speed due to loss of traction. The power transmitted will flow to the wheel with the most friction to synchronize its rotational speed and regain traction.

Other cars have a selective arrangement that permits the driver to shift the drive mode. You may notice a range indicator of the drive mode, such as 4L and 4H four-wheel drive. You can use 4H to improve traction on the roadway during snowy paved roads or rainy weather if you’re going at a high pace, not faster than 55MPH. On the other hand, you can use the 4L range strictly for harsh off-road conditions and sluggish speeds since it requires more traction and torque multiplication.





4WD LightA 4WD light illuminates on the dashboard to signify that your vehicle is engaged in four-wheel-drive mode. The light indicator will turn a solid color, commonly orange or green, once the 4WD is effectively activated. This light indicator can be switched off manually with the touch button when you switch the drive mode from 4WD back to 2WD. A fully advanced four-wheel drive automatically switched the light indicator on and off since it identifies and engages 4WD mode when the sensor detects a need for extra traction.

On the other hand, when you notice a repeated flashing of the 4WD light for more than 30 seconds, it notifies that there’s a problem with your drivetrain system, and the 4WD mode isn’t working. You will find this notification unpleasant and inconvenient. Thus, it’s usually a good idea to contact a service technician for advice if you’re having problems.
A-pillarA-pillar is the structural component of an automobile’s frame found between the windshield and the front doors. It is known as the A-pillar since it is the first frame supporting and joins the side of the vehicle’s body to the roof structure and holds the front windshield. Strong steel alloys make up the A-pillar to ensure that it can withstand a crash or a rollover and comply with safety regulations. In most cases, the A-pillar blocks the driver’s vision, resulting in a blind spot. As a result, some automakers slimmed and chamfered the A-pillar to reduce blind spots, improving the driver’s visibility.
A/C CompressorOne of the essential components of your air conditioner is the compressor. The compressor is a belt or electric-driven pump designed to raise the pressure of the refrigerant. Increasing the pressure means raising the temperature, which forces the refrigerant to circulate through the system. High-temperature refrigerant vapor will condense rapidly in the condenser by releasing heat to the surroundings. More importantly, the compressor not only helps in the cooling process. It also ensures that the machine operates efficiently and continuously.

For the air-conditioning system to perform at its best, it requires a properly functional compressor. On the contrary, the compressor contains a lot of moving parts and is prone to breaking. If the compressor fails for any reason, the machine may make noises, provide insufficient cooling, or your vehicle may start up slowly. You should be able to drive your car with a broken compressor. But there are a few things to keep in mind, though. It should not affect the belt tension or the operation of other belt-driven accessories as long as the compressor wheel rotates smoothly without wobbling or making noises.
ABSABS is an electrical system that detects and prevents wheel lock-up. It consists of sensors installed at each wheel, which monitor and adjust the wheel speed through the data programmed in the ECU. These sensors will detect when one wheel rotates at a different rate than the others. If it detects a wheel rotating more slowly while braking, it is an indication that the wheel is locking or soon to lock. The electronics then activate a relief valve to reduce brake pressure in a pulse rate until its rotation is equal to the other wheels.

When the sudden braking force is applied, the wheels may become locked due to friction and high brake pressure, resulting in rotational halting. In this situation, the vehicle remains in motion, and tires lose their traction on the road that may cause the driver to lose control of the vehicle’s steering. The situation becomes even worse, which an accident happens when the car is more likely to slide and crash. To prevent this, ABS boosts braking force by preventing skidding, increasing friction between the tires and the ground, allowing the driver to keep control of the steering system while the wheels continue to revolve.
ABS LightThe ABS light is a symbol on the dashboard that notifies the driver when the ABS kicks in when braking and goes off when the brake is released. In modern automobiles, when a vehicle with ABS is turned on, the light, usually yellow, or orange glows as part of a system check. If the ABS indicator light remains lighted after the system check or is not in use, it means that there is a problem with the vehicle’s brake system.

To simply put, the onboard computer has detected a potential ABS problem, and the ABS is no longer operating. If you ignore the ABS light, safely stopping your automobile may become impossible. You may avoid this problem that would otherwise degrade your vehicle’s performance by taking a proactive approach to ABS maintenance.
AC OutletAn AC outlet is a plug that produces the same amount of electricity as your home. The output voltage in North American versions is usually 115 volts. Most modern automobiles equipped with this feature have a maximum power rating of roughly 150 watts, which is sufficient for most portable electrical devices.

Typically AC outlet act as a mobile charging station to provide electrical power for portable equipment used in or around your vehicle. However, there are some limitations to the outlet and some precautions to follow when utilizing electronic devices. You can check it in your owner’s manual to see what voltage and guidelines are provided in your vehicle.
Active SuspensionAn Active Suspension is an electronic-controlled type suspension system that raises or lowers the ride height to improve the performance and towing capability of the vehicle. It works by continuously sensing changes in the road surface and relaying this information to the outlying components through the ECU. With improved computer control, the driver can alter numerous options of suspension travel and reaction while driving. Depending on the input choices, the system elevates or lowers the body, keeps the chassis level, and absorbs the energy associated with the vertical motion of the wheels efficiently as possible for improved handling in all sorts of terrain.

Active suspension is also known as computerized ride control and uses hydraulics or electromagnets to operate. In the active suspensions that adjust hydraulically, sensors are responsible for monitoring the movement and ride height of the vehicle. When the system needs to modify performance or ride height, it activates a hydraulic pump that pressurizes the liquid in the shocks. This process will also adjust the suspension firmness and the ride height following the desired preferences.

On the other hand, an electromagnetic-controlled active suspension functions similarly to a hydraulically-controlled system. The only difference is that instead of pumps, these system alters the ride height using electromagnet motors. More importantly, this system is known for responding faster and using less energy than hydraulic suspension. Thus, changing the riding state of the vehicle depending on the terrain or driver preferences improves handling, road feel, reactivity, and safety.
Adaptive Cruise ControlAdaptive Cruise Control is a system featured in the latest automobiles that assists in maintaining a safe distance from the car in front while keeping a certain speed. ACC automatically modifies the vehicle’s cruising rate, which keeps it at a steady pace and warns the driver about potential forward crashes. The vehicle’s sensing technology constantly measures the distance to avoid a collision. These sensors include cameras, lasers, and radar equipment, allowing ACC to calculate the distance between two cars or other objects around your vehicle.

Adaptive Cruise Control system comes in different types, such as Binocular Computer Vision Systems, Assisting Systems, Multi-Sensor Systems, Predictive Systems, Radar-Based Systems, and Laser-Based Systems. On the contrary, unfavorable weather conditions and environmental factors may cause the system’s sensors to malfunction. To achieve optimum safety outcomes, the driver must continue to exercise safe driving habits that function with the ACC system.
Adaptive HeadlightsHeadlights that adapt to changing conditions are known as adaptive headlights and can improve nighttime visibility and illuminate road hazards more effectively and quickly than traditional headlights.
These lights can react to the turns you make, ensuring that they are constantly looking forward since they can move from side to side. These headlights are helpful when driving on a winding road, illuminating the road ahead of you where it is most needed. Vehicles with adaptive headlights are most likely to avoid nighttime curve crashes.

Adaptive headlights are connected with electronic sensors, which monitor the vehicle’s speed, steering wheel direction, and side-to-side motion. These sensors detect which way and how the lights will react based on the data programmed in the ECU and tell you exactly where your headlights should point. Small electric motors are attached to the sensors within each headlamp shell. These motors operate by turning the headlights in the appropriate direction.
AdBlueMost automotive manufacturers are subject to regulations, many of which are increasingly related to environmental concerns. The most recent emissions restrictions, known as Euro 6, aims to reduce nitrogen-oxide emissions. Many new diesel-powered vehicles inject a tiny quantity of AdBlue into the exhaust fumes to comply with Euro 6 requirements. An AdBlue is a colorless, non-toxic solution of water and chemical found in urine called urea. The urea used in Adblue is pure and of a higher quality. When AdBlue solution reacts with exhaust emissions, the hazardous mono-nitrogen oxides in diesel exhaust are broken down, making the exhaust clean. .
AdBlue malfunctionWhen the computer identifies a problem with the system, the DEF malfunction light or the AdBlue fluid level alert will appear. This indicator is usually yellow, and it should turn off once you’ve added more exhaust fluid to the tank. It could also suggest a problem with the delivery system or the DEF level sensor, or it could mean you’re using the wrong fluid. Don’t panic if the warning light comes on for the first time. You’ll have plenty of time to replenish. But if you don’t top up, you’ll soon run out of AdBlue and be unable to start your car. If you don’t fill the tank, it will turn red, signaling a no-restart situation. You will not be able to restart the engine once it has been shut off if the indicator light is red.
Adjustable ShocksAdjustable shocks consist of an oil-filled tube with a piston that moves up and down inside the cylinder. It allows the front tires to lift easily, which aids weight transfer to the rear tires. The advantage of an adjustable shock is that it can be adjusted to add a little extra rigidity to the suspension. Piston valves control the degree of damping by regulating the pace at which oil flows past the piston.

Adjustable shocks can be made softer or harder by following the manufacturer’s instructions. The adjustment changes the orifice calibration so that the fluid passes through the piston faster to give a softer ride. Some brands can be adjusted to harder levels to compensate for wear. Allowing less oil to get through may result in stronger shocks while allowing more oil to pass through results in less dampening and a softer ride. When the car is not loaded or under typical driving conditions, the shocks can be alleviated of compression firmness and switched to soft. When you change the shock looser or stiffer, you’re altering both the rebound and compression. You can control the rebound and compression individually with double adjustable shocks.
Air BagAirbags are additional safety devices that operate best and consider as one of the essential safety developments in recent decades. They are inflatable cushions fitted into a car that protect occupants when the sensors begin measuring the impact severity if a collision occurs. If the impact is hard enough, the sensors activate inflators, which fill the bags with gas in just a second. An airbag slows down the motion of the driver or passengers in the case of an impact, which minimizes your upper body and head colliding with the vehicle interior or objects outside the vehicle.

Airbags don’t usually need to be serviced until they deploy in a collision. You can replace your airbags at a repair facility that employs Original Equipment Manufacturer replacement parts to verify that the new airbag is not a knockoff. In some cases, counterfeit airbags may fail to deploy or emit metal shrapnel during an accident.
Air CooledThe process of reducing air temperature by dissipating heat is known as air cooling. The air-cooled system uses air-reducing fins to transport and discharge heat, resulting in improved airflow and lower temperatures. The system’s role is to have a constant current of air running over the hot engine surface from which the heat ejected.
Air FilterAn air filter is responsible for keeping hazardous particles out of the engine, ensuring that only clean, debris-free air reaches the engine’s combustion chamber. A clean air filter allows the engine’s mechanism to work by allowing the proper ratio of air to fuel since airflow is necessary for the operation. If the air filter is clogged, contaminants may endanger the engine parts producing corrosion, and abrasion, and may cause the engine performance to deteriorate, potentially resulting in engine failure.

Changing the air filter of your vehicle is necessary to extend the life of your engine and keep it performing at its best. Additionally, air filters should be checked and replaced regularly to optimize fuel efficiency and acceleration. Generally, you replace your air filters every 12,000 to 15,000 miles, but these intervals should be lower depending on the driving condition.








Air InjectionThe air-injection or AIR system is an exhaust-emission-control system that uses a low-pressure pump to inject fresh air into the exhaust system. It reduces hydrocarbons and carbon monoxide emissions by injecting fresh air into the exhaust gases after leaving the combustion chamber. The air causes the unburned and partially burned fuel to continue burning. This system reduces the amount of these pollutants and helps convert them into carbon dioxide and water.

The air enters the exhaust manifold through the nozzles positioned opposite the exhaust ports. When the air hits the hot exhaust gas coming from the exhaust port, much of the hydrocarbons and carbon monoxide changes into water and carbon dioxide. The air-injection system requires no routine service except to replace the air filter if specified in the maintenance schedule. Most air pumps have a centrifugal filter which requires no service, so check the air-pump drive belt periodically for tension and wear.
Air PumpThe Air Pump, also known as the smog pump, was created to provide new, clean, and pressured oxygen into the exhaust stream. Since exhaust gases are hot as they leave, injecting oxygen at this point permits unburned hydrocarbons to be burnt as they travel down the exhaust system and eventually out the tailpipe. An air pump is a component in the secondary air injection system designed to operate continuously. This mechanism is essential in assisting automobiles in meeting government emission regulations.
Air ScoopTypically, air scoops are the bumps found in most performance cars, especially in muscle models. Its purpose is to transfer cooler, less dense air into the engine compartment, increase airflow to the engine, allowing it to cool faster and produce more power. Air scoops create a ram effect, which causes the air to be slightly compressed and forced into the engine’s intake. When cold, pressured air is burned, additional power is generated to boost the performance of your car.
Air-Fuel RatioThe amount of air in proportion to the amount of fuel is known as the air-fuel ratio. The engine cannot perform efficiently if the fuel is too much or too little to the air volume. In most cases, the fuel-to-air ratio of a gasoline engine must be just correct to ensure good combustion in the cylinders. A suitable air-fuel ratio is crucial because the amount of air-fuel mixture drawn into the cylinders determines engine power performance.
Airbag Warning LightAirbag Light is an illuminated indicator that there is a malfunction in the airbag system. The most typical reason for the airbag light to illuminate is that the airbag system has been switched off or deactivated. There could be a couple of reasons for this over which you had no control. It may be because the backup battery that operates the airbags may have depleted. A crash sensor, SRS module, or other airbag components may be malfunctioning. Alternatively, the sensor in the passenger seat that decides whether or not the airbag should be active could be malfunctioning. Thus, an airbag scanner is required to read and clear the fault codes that trigger the airbag warning light.
Airbag ScannerThe Airbag Scanner is a diagnostic tool for the SRS system’s faults or problems. Most scanners can clear soft codes after resolving a system’s issue. The airbag scanner also has an improved data stream, allowing you to view live data feeds from advanced systems like ABS, SRS, transmission, and engine. Codes indicate a problem with a component of the SRS system, such as the driver airbag, seat belt, or impact sensor.
AlternatorThe alternator, also known as an AC generator, is a device that converts mechanical energy from the engine into electrical energy. It is driven by a belt at two to three times the crankshaft speed by the engine crankshaft pulley. While the automobile’s engine was running, the alternator produced electricity to recharge the battery and supply the electrical components with the amount of electricity required.

In most automobiles, alternating current alternators are preferred over direct current dynamos in electric power generation performance and longevity. The alternating current produced by the alternator is rectified just before output since most of an automobile’s electrical components require direct current.
Anti-FreezeAntifreeze is a liquid added to the engine cooling system to transfer heat away from the engine while running, as well as prevent the engine cooling agent from freezing while shut down during cold weather conditions. If only water was used as the coolant and would freeze if the temperature dropped. It would stop coolant circulation, and the engine would overheat. The coolant is the liquid that circulates through the cooling system, removes waste heat from the engine, and delivers the heat to the heat exchanger known as the radiator. The radiator cools the hot antifreeze taken from the engine then circulates it back to cool the engine.

The most commonly used antifreeze is ethylene glycol. A mixture of haft water and half ethylene glycol is the recommended coolant for year-round use in most cars. Additionally, antifreeze is usually green or blue-green with a dye for identification. It allows the antifreeze to serve as a leak detector. The distinctive color makes it easier to locate a leak. Antifreeze also contains additives to help prevent rust and corrosion from within the engine. These include a corrosion inhibitor and a foam inhibitor. Corrosion or rust can shorten the life of metal parts. It also forms an insulating layer that reduces heat transfer from the metal to the coolant.
Anti-Roll BarThe Anti-Roll Bar, also known as sway bar or stabilizer bar, helps control body roll when cornering or driving on rough or uneven surfaces. It usually connects between the two lower control arms. When the vehicle moves around a curve, the body leans outward. It causes the lower-control arms to move in opposite directions, twisting the sway bar.

However, the sway bar resists being twisted, which stiffens the suspension during turns so less lean out or body roll results. Anti-Roll Bar action may also occur if one tire hits a bump or pothole while the other does not. But it has no effect while the vehicle is straight ahead on a smooth surface.
Anti-theftIn vehicle security systems, anti-theft causes the horn to sound and the lights to flash if someone tries to break into your vehicle. There are several different ways to trigger the alarm. Typically, the driver sets the alarm by operating a switch when leaving the car.

Opening or forcing the hood, trunk, tailgate, or door to open also causes the alarm to trigger. Many vehicle security systems include a starter interruption, which prevents starting the engine after any forced entry. Some vehicles automatically disconnect electrical circuits to stop a car from starting or shut down the engine.
Aspect RatioIn tire terminology, the ratio between the height of a tire from the wheel rim to tread, and its width, from sidewall to sidewall, is known as the aspect ratio or tire’s profile. The first tires were circular tubes with 100 percent aspect ratios. It was later discovered that a tire handled better when it was mounted on a wider rim, making tires wider without increasing their height. These low-profile tires put more tread on the road and gave better handling, better load-carrying capacity, and longer life than the old symmetrical tires.
Auto Stop/StartAn Auto Stop/Start is a feature on your vehicle, which helps improve fuel efficiency and reduce greenhouse gas emissions. When the car comes to a complete stop, the engine automatically pauses the vehicle operation since the speed falls below a particular speed limit. With this technology, your vehicle will conserve the fuel would have been consumed by the engine when the car stops at a traffic light and shifts the transmission to neutral. Your engine will restart back by releasing the brake pedal or slightly moving the steering wheel.
Automatic TransmissionThe automatic transmission uses a hydraulic system to shift the gears and transmit power automatically. The transmission shifts into higher gears as the car’s speed increases and then shifts to lower gears when climbing hills. Simply pushing down on the accelerator pedal controls the speed of the vehicle. The advantage is easier driving, but with most automatics, there is a loss in fuel economy.
Auxiliary InputIn your car, an auxiliary input or AUX connects audio devices straight to your speaker. It transfers sound to the multimedia system, allowing you to play music from your phone, tablet, mp3 player with a compatible 3.5mm AUX connection through the car’s speakers. AUX is preferable if you want variety, affordability, and superb music quality, but it tends to wear out faster. Most people won’t notice if AUX converts audio from digital to analog, which may cause noise or information loss.
AWDSome passenger vehicles have all-wheel drive mode or AWD. It is a version of four-wheel drive used in vehicles primarily for on-road use. It provides improved traction, especially on slippery or snow-covered road surfaces. When the wheels on one axle slip, the system automatically transfers torque to the other axle with better traction.

A two-speed transfer case is not used, so there is no low range for off-roading. Other AWD vehicles have front-wheel drive with auxiliary rear-wheel drive or rear-wheel drive with auxiliary front-wheel drive. Others have the gearing to drive the auxiliary axle built into the transmission or transaxle.
AxleAn axle is a shaft or a beam with a wheel at the end supporting a vehicle, on which one or more wheels turn. Axles that transmit power are called live axles. A live axle assembly contains two axle shafts that deliver power from the differential gears to the wheels. Its made up of special alloy steel, and these axle shafts have splines at their inner ends that fit into matching splines on the differential side gears. On the other hand, a dead axle or non-drive axle carries part of the weight but does not drive the wheels. A drive axle on which the wheels can pivot for steering is a steerable drive axle. It is commonlyly used on four-wheel-drive trucks.
B-pillarB-pillar, also known as a center pillar, is the vertical roof support structure. This pillar is made of steel and welded to the roof panel commonly found between the front and rear doors. A B-pillar on four-door sedans is often a closed steel structure welded to the car’s rocker panel and floor pan at the bottom and the roof rail at the top. On the other hand, there is no B-pillar in a coupe or convertible vehicles, which there is nothing to attach to the back doors, while the back doors of a sedan or SUV are attached to the B-pillars. In the case of impact, the qualities of a B pillar determine the safety of the vehicle’s passengers.
BackfireBackfire occurs after releasing the accelerator pedal suddenly on a carbureted engine. Some unburned fuel reaches the exhaust manifold and mixes with the fresh air injected. Sparks in the hot exhaust gas from the next cylinder that fires ignite the mixture. Backfire refers to the pop or bang heard through the air intake or exhaust system. It can be caused by an excessively rich or lean mixture. If the backfire is in the exhaust system during deceleration, the cause is a rich mixture. Lean mixtures usually cause a pop back in the carburetor.
Balance ShaftA Balanced Shaft is a solid cylindrical metal rod placed on one side of the crankshaft and linked together with gears. It is a feature to improve the crank mechanism balancing efficiency since vibrations are produced inside the cylinder block when the internal combustion engine is running. Although each type of engine has its own set of benefits, none of them can remove vibration. Hence, a separated balance shaft may be necessary to absorb excessive inertia and vibration, refining the engine. This shaft rotates in opposite directions and faster than the crankshaft during operation, which dissipates the inertial forces generated by the crankshaft’s revolution.
Balance TiresBalance Tires or wheel balancing is the process to check the wheels and tires assembly for their unbalanced weights. Proper wheel balance is one factor promoting the longevity of a tire’s lifespan. Static and dynamic are two types of wheel balancing methods. Dynamic balancing is usually the preferred method, which uses an off-the-vehicle wheel balancer. This method involves spinning the wheel and tire on the wheel balancer to identify the heavy spots, then crimping lead weights to the rim to compensate, rebalancing the wheel.
Ball JointThe ball joint is a stud with threads on one end and a ball on the other, and the ball seats in a steel socket, with nylon or sintered-iron bearing between the two. It has a flexible ball-and-socket that mounts in the outer ends of the front suspension control arms. It provides a pivoting joint that attaches the steering knuckle to the control arms, which move only up and down. It allows the steering knuckle and wheel to turn in and out for steering. It is sealed by a rubber dust cover that keeps out dust and water and keeps in lubricant. Most ball joints can be lubricated through a grease fitting or removable plug.
BatteryThe automotive battery is an electrochemical device, which means its operation depends upon chemical and electrical actions. The function of the automotive battery is to supply a sufficient amount of electricity to operate the starting and ignition systems while starting the engine. It also acts as a voltage stabilizer by providing electricity to the automobile’s electrical components, such as headlights and other electrical accessories, especially when the alternator can’t carry the electric load.

On the other hand, the battery is limited in its capacity and not capable of providing all the power required by the automobile. When current is withdrawn from the battery, chemical actions take place to produce the current flow. In a sense, the chemicals in the battery are used up by this action. Thus, after a certain amount of current has been withdrawn for a certain length of time, the battery becomes discharged. To recharge the battery, current from some external source, such as an alternator or battery charger, must be forced through it in the charging direction. Generally, a fully charged battery should have a voltage of more than 12.6 volts and has an expected lifespan of 3 to 5 years before replacement. However, its lifespan also depends on the demands of the vehicle’s electrical components as well as the driving habits, which all affect the battery’s longevity.

A battery has a limited life, but some of these conditions can also shorten its lifespan. Battery life can be shortened by high temperatures caused by overcharging or engine heat, while low temperatures can induce freezing or weak electrolyte. In addition, overcharging produces gassing and excessive internal heat, resulting in a loss of electrolyte level. Loss of electrolytes also happened due to a cracked case and poor maintenance. Undercharging causes sulfate to harden on the plates, making it tough to remove with normal charging. Corrosion raises electrical resistance, lowering the available voltage and charging efficiency. Lastly, the loss of active material from the positive plates may also result from repeated cycling from fully charged to fully discharged.
Battery BracketA battery Bracket, commonly known as batter hold-down, is a metal brace or base clamp that secures the battery in place. It prevents the battery from moving when the vehicle drives up and down slopes, corners, bumps, potholes, and through hard stops. When not installed, the battery may potentially tip over and fails the vehicles’ operation.
Battery LightTypically, the battery light glows during ignition and then turns off once the engine is running. It’s not a good idea to drive with a battery light is on. If this light indicator comes on, turn off the unnecessary electricity components in your vehicle to preserve the remaining charge in the battery. It tells that something is wrong with your charging system, which could be a weak battery, a faulty voltage regulator, or a failing alternator. When the alternator in your vehicle is not working, the battery can quickly lose charge if disregarded. If the charge in the battery completely drains, the vehicle will lose its power and stop its operation.
Bed LinerA Bed Liner is a heavy-duty plastic or spray-on protector necessary for keeping the cargo and vehicle’s bed. The Bed liner will protect bed surfaces from rusting, corrosion and provide a non-slip surface. It ensures your vehicle’s bed is in good condition when traveling. Typically, drop-in liners and spray-on liners are the two most common forms of bed liners. The bed liner is best for driving and moving any goods or cargo or driving in an exposed environment with unpredictable elements.
BHPBrake Horsepower (BHP) refers to how much power an engine can do without any losses such as heat and noise. BHP also means that a braking device is used to determine the power that a running engine delivers. It is measured by the amount of resistance provided by a brake, which indicates the machine’s useable power. It can also be calculated by the work of an actual horse to determine the engine’s horsepower rating. For instance, a 270 horsepower engine can produce the amount of work of 270 horses. As a result, brake horsepower affects the vehicle’s top speed and acceleration.
Blind SpotA Blind Spot refers to an area around your vehicle that cannot be seen by looking from the vehicle’s view mirrors. Typically, some areas are difficult or cannot be seen while driving, which is dangerous to the driver’s safety. These areas can be large enough to obstruct the driver’s view, and it’s difficult to tell if there are vehicles or even pedestrians next or behind your vehicle.
Block HeaterThe Block Heater is an electrically-powered device used to pre-heat the coolant in the engine to start in severely cold weather, especially when the temperature drops to -15 degrees Celcius below. Most diesel vehicles typically use an engine block heater to keep the temperature from falling too low. Block heater warms the engine coolant and the engine, which removes the chill on the engine oil.
This device is sometimes bolted into the block through an expansion plug hole or attached to the bottom radiator hose. Plugging in your automobile with a block heater before starting can reduce pollutants and improve the vehicle’s fuel economy. However, the block heater does not need to be plugged in overnight since the heat it produced will be lost to the air, draining and wasting the charge in the battery.
Boost PressureBoost pressure refers to the amount of atmospheric pressure that surpasses the normal pressure a manifold can take produced by the supercharger or turbocharger during operation. Turbo or supercharger will carry more air and pressurize them before entering the engine. Forcing more air into the engine combined with more fuel mixture makes greater explosion inside the cylinders to generate more power, making the engine more efficient. Modern turbocharged vehicles enhance fuel economy and produce more power by metering the fuel and air with extreme precision. Thus, a bigger explosion in the combustion chamber comes with more power.
BoreBore refers to the diameter of each cylinder. It acts as a seal against combustion gases and lubricant infiltration into the combustion chamber. Also, its role is to transfer heat from the piston to the liner. In the case of a new cylinder block, there can be a few variances in the cylinder bore diameter. Typically, there are three standard-sized cylinders bore diameters. A bore size code is stamped into the top of the cylinder block for each respective cylinder.
Brake BoosterThe hydraulic brake booster mounts on the firewall behind the master cylinder. Hydraulic pressure supplied by the power-steering pump assists in applying the brakes. When the engine is running with the brakes released, pump pressure goes to the steering gear. Pushing down on the brake pedal forces the brake-pedal pushrod slightly forward. A pivot arm or level connects the booster input rod to the spool valve. The movement of the brake pedal forces the spool valve forward, which sends additional pump pressure into the space behind the power piston. The increased pressure moves the power piston forward, which pushes the master-cylinder pushrod into the master cylinder with a greater force than applied by the driver.
Brake CaliperBrake Caliper is a hydro-mechanical C-shaped device that applies brake pressure to the brake rotor. It is mounted on the front suspension and clamps friction pads against the brake rotor. Conventional vehicles used fixed-caliper brakes, which required two or four hydraulic cylinders per wheel. The single-cylinder makes the sliding-caliper brake cheaper to manufacture and more reliable because it has fewer hydraulic seals.
On the other hand, most disc brakes have sliding calipers. These are mounted so that they can slide from side to side a fraction of an inch. When the driver steps on the brake pedal, hydraulic pressure pushes the brake pad against the rotor. Reaction to this pressure moves the whole caliper on its mounting, pulling the other brake pad against the rotor, too.
Brake CylinderBrake Cylinder, also known as Wheel Cylinder, converts the hydraulic pressure from the master cylinder into mechanical movement. When the driver steps on the brake pedal, brake fluid flows from a pressure chamber in the master cylinder through brake lines to each wheel cylinder. The wheel cylinder pushes one end of each brake shoe against the drum. The other end of the brake shoe is supported by a pivot point called the anchor. It has two pistons, with seals or cups, and a spring in between. As the pressure increases, the pistons overcome the brake-shoe return springs and push down the shoes outward into contact with the drum.
Brake DragA brake drags when a brake shoe does not move away from the drum as the brakes are released. This failure could be caused by the piston in the wheel cylinder sticking in its applied position. The vent ports are not open to relieve the pressure by allowing fluid flow back into the reservoir. When the hydraulic pressure is trapped in the lines of the wheel cylinders, the shoes cannot retract and causes the brakes to drag. Brake dragging can also be caused by swollen seals or cups in the master cylinder when oil enters the system. Oil can cause the piston cups to swell. Then they cannot clear the ports and release the pressure, clogging the ports causing the same condition.
Brake DrumBrake Drum is a cylindrical metal component mounted on a vehicle’s wheel to form the outer shell of the brake. The brake shoes create friction against the drum’s inner surface when pressed against the drum to slow or stop the drum-and-wheel rotation of the vehicle for braking.
Brake FadeBrake fade is a temporary reduction or fading out of braking effectiveness. Fading occurs when the brake lining overheats from excessively long and hard brake application, as when coming down a hill. In this case, normal braking usually returns after the brake cool. On the other hand, fading may also occur after driving through the water and getting the linings wet. The water reduces the friction between the lining and the drum. In this case, normal braking usually returns after the linings have dried.
Brake FluidBrake fluid is a chemically-inert hydraulic fluid used to transmit force and motion. It also lubricates the piston in the master cylinder, wheel cylinders, and calipers. The Department of Transportation classified the brake fluid into DOT 3, DOT 4, and DOT 5. DOT 3 brake fluids are hygroscopic that absorb moisture mostly used in automobiles. DOT 4 brake fluids are also hygroscopic and used for disc-brake systems. DOT 5 brake fluid is silicone-based and can take even higher temperatures but is incompatible with DOT 3 or 4 fluid and must not be mixed with either of them. Brake fluid is stored in air-tight containers to protect it from moisture. Master cylinders have flexible diaphragms or sealed caps that cover the reservoirs, preventing the air from contacting the fluid.
Brake Fluid ReservoirA Brake Fluid Reservoir is a canister that is attached to the master cylinder. It holds the brake fluid used for brake application by storing and protecting, allowing your hydraulic braking system to function at its best. If the level is insufficient, add the appropriate brake fluid for your vehicle into the brake fluid reservoir. The brake system may need to service bled if the brake fluid reservoir is empty or unless there is a leak in the system. The brake fluid level should be near or reach the brake fluid reservoir recommended marking.
Brake LightA Brake light or a flashing red light on the dashboard instrument panel could indicate a low or nearly empty brake fluid in your brake fluid reservoir. It could also indicate an error with the brake’s hydraulic system of your vehicle. When your brake light comes on, it also tells you that the emergency brake or parking brake has engaged since most cars have a sensor that detects whether or not the parking brake is applied. The fluid level will drop if there is a leak in the brake system, causing your brakes to fail and triggering the brake light to illuminate. It is risky to drive while the Brake Warning Light comes on since it indicates that your brakes are malfunctioning and should be serviced as soon as possible.
Brake LinesBrake lines are the tubes and hoses connecting the master cylinder to the wheel cylinders or calipers in a hydraulic brake system. Brake lines deliver the pressurized brake fluid to the wheel ends. These lines are made of steel found under the floor pan and sometimes wrapped with wire coverings to protect them from flying debris. The ends are flared with either a double flare or an ISO flare, which provides maximum protection against leakage. A shot flexible brake hose or flex hose connects the steel brake lines to the wheel cylinders or calipers.
Brake Pad Wear IndicatorThe Brake Pad Wear Indicator is a monitoring device that will alert the driver before the brake pads reach their worn limit, which usually appears on the dashboard panel. Some brake pad wear indicator comes in a small piece of metal that sticks out next to brake pads and grinds against the rotor. If the grinding, growling, or screeching sound from your brakes is noticed, it could be a sign to check the wear on the brake pads and fix if there is something is wrong.
In most cases, the brake pads should be replaced every 10,000 to 20,000 miles to keep wear to a minimum. However, to keep the brakes in good shape, it is recommended to replace the rotors every 50,000 to 70,000 miles.
Brake PadsFriction occurs when the brake pads come in contact with the rotor. The rotor, which is directly attached to each wheel, receives pressure from your brake pads. This pressure is required to slow down or stop your vehicle from moving. Organic, ceramic, and semi-metallic materials are the most common types of brake pads. Ceramic brake pads provide outstanding braking performance and heat dissipation, which are great for most driving situations.
But most modern cars sold in the United States come with organic brake pads installed by automobile manufacturers. Usually, there is a slot in the center of some brake pads that serve as a wear indicator. It tells if the brake pads appear to be nearly thin or wear out past a certain point. Thus the brake pads are replaced frequently since the thickness of the brake pad determines its lifespan.
Brake ShoeDrum brakes have brake shoes installed as part of their mechanism. Brake shoes are usually crescent-shaped components with a rough friction substance attached to one side and secured to the backing plate with hold-down hardware. Each drum brake system consists of a leading and trailing brake shoe activated by the wheel cylinder’s hydraulic pressure. The brake shoes are pulled outward when the brake pedal is pressed, pushing against the inner side of the brake drum and slowing the wheel of the vehicle.
The ability of the brake shoes to slow the car may be impaired if they get too worn or overheated, reducing its responsiveness when braking. As a result, the vehicle takes longer to halt when the brakes are used, particularly in high-speed or heavy-braking circumstances. Increased wear on a set of brake shoes can be caused by several factors, including faulty hardware or warped brake drums.
Brake SystemA Brake system is a safety feature system responsible for slowing down, stopping, and keeping the vehicle’s movement. The main force that acts and plays an essential function in the braking system is the frictional force. Every brake works on the principle of friction, which opposes any force, and may increase by applying brakes. The brake system converts the kinetic energy of the moving vehicle to heat energy through friction.
During operation, the driver depresses the brake pedal, hydraulic pressure is created in the master cylinder, and brake fluid is pumped through a series of brake pipes and hoses going to hydraulically activated pistons in each wheel’s hub assembly. Thus, forcing the friction material on your brake pads or shoes onto rotating parts. To simply put, when the system is in good working operation, it aids in preventing possible collisions leading to an accident and a potential tragedy.
Braking AssistThe Brake Assist is a system designed to increase the braking power or pressure applied during emergency stops. The system delivers full braking force to ensure the automobile comes to a complete stop as quickly as possible when the system detects the driver pounding on the brake pedal application. Typically, it recognizes when it needs to intervene since it monitors typical driving tendencies and is proven to help avert potential collisions.
Branded TitleA branded title indicates that the vehicle was repaired, had its odometer reset, involved in an accident, and rebuilt before being sold. The branded title is also known as a salvage title, which voids the existing warranty on the vehicle. It is also a formal sign indicating that the vehicle have been damaged and considered a total loss by an insurance company, even if it has been restored.
You can’t insure a car with a salvage title because it isn’t roadworthy but having a branded title on the vehicle is not bad. However, integrity and safety may endanger even if the fixes may appear to be in good condition on the surface. A vehicle with a branded title can still be used if the repairs are done correctly and pass all safety and operational inspections.
Breaker ArmThe breaker arm, also known as the movable-point arm, is an insulated movable arm that mounts the other side of the contact point in the ignition distributor. The arm swings back and forth on a pivot as the cam lobes push on the rubbing block to open the points. A spring attached to the breaker arm closes the points. When the points close, this connects the coil primary winding to the battery.
A magnetic field builds up in the coil. The next lobe pushes the breaker arm away from the stationary contact point as the breaker cam rotates. It opens the points and stops the current flow. The magnetic field collapses, and a high voltage surge results.
BushingA bushing, also known as rubber bushing, is a type of vibration isolator. It is a small rubber or polyurethane suspension component used to isolate vibration, offer to cushion, and minimize friction between metal parts on the vehicle. It also acts as an interface between two pieces, functioning as a buffer and absorbing some of the energy generated by interaction. Additionally, other bushings can be made up of bronze, steel-backed babbitt, plastic, nylon, or cast iron.Bronze is a common choice for bushings because it comes in alloys and compositions to be used in a wide range of applications. Bronze bushings are more durable than other materials and are less likely to crack or distort. Among other materials, the bushing material must be able to support and protect the component. By acting as a cushion between parts and reducing the amount of movement in the joints, any bushing reduces road noise, vibration, and harshness. On the contrary, bushings wear out and allow more movement. Clunking or scraping noises, uneven tire wear, and poor handling and braking response are signs of damaged bushings. When turning the wheel or braking forcefully, the driver may feel a shimmy from the front or hear clunking or rattling noises. Drivers may also suffer sluggish steering or poor handling as a result.
Bypass FilterBypass filter contains a significant pressure differential, which causes the oil to flow very slowly through them, removing tiny impurities. Contamination is the sole thing that limits the oil utility since it does not degrade over time. Many of these pollutants are removed or diluted via bypass filtration. The oil runs from the bypass filter back to the sump, bypassing the engine, resulting from bypass filtration. It expands the engine’s overall sump size, which helps to dilute the metal concentration in the oil. The bypass flow of the oil is pushed solely for filtration and does not flow directly to the engine’s main lubricating system.
C-pillarC-pillar is the rearmost support situated between the B and D pillars in sedans and hatchbacks vehicles. Typically, it is the vertical support pillars that run along each side of the back window. On the other hand, on SUVs, minivans, and wagons with enlarged cargo areas, the C-pillar vertical structure is found behind the rear door, where vertical supports in these vehicles are situated at the rear.
CamberCamber, also known as tire wear angle, refers to the inward or outward tilt of the wheel from the vertical when viewed from the front. The amount of camber angle measured in degrees between the tire centerline and the vertical. A wheel that tilts out at the top has positive camber. If it tilts in, it has negative camber. The wheel suspension in most vehicles is usually adjusted to give a slight outward tilt or positive camber.
The wheels should run straight up and down with zero camber if the vehicle is loaded while running. It means that the wheels should be perpendicular to the road so that the tire treads contact the road evenly. This position minimizes tire wear by distributing the car’s weight uniformly across the tread. Tilting the wheel puts more load and wear on one side of the tire tread. Incorrect camber at both wheels can cause heavy and unstable steering and wander.
The camber goes negative when the tire hits a bump and moves up. On the other hand, camber goes positive when the tire drops into a hole on the road. It is caused by the unequal-length control arms of the suspension system. For this reason, unequal camber can contribute to low-speed shimmy. Sagging spring can also change camber. If this happens, it affects the camber of the diagonally-opposite front wheel.
CamshaftA Camshaft is a shaft in the engine, which has a series of cams for operating the valve mechanisms. The camshaft is driven through gears by the crankshaft and mounts overhead on top of the cylinder head. Some engines use a combination of timing chain and timing belt to drive the camshafts. When the camshaft is driven by a timing chain, the crankshaft and camshaft rotate in the same direction. With gear, the camshaft rotates in the opposite direction.
Most camshafts have a cam for each valve in the engine. In addition, the camshaft has another cam to operate the fuel pump. It also has the gear to drive the ignition distributor and the oil pump. The camshaft sprocket or gear is twice as large as the crankshaft sprocket. It gives a 1:2 gear ratio, which means the camshaft turns half the speed of the crankshaft in a four-stroke cycle engine. Thus, every two crankshaft revolutions give one camshaft revolution and one cycle of valve action.
Carbon FiberCarbon Fiber, also known as graphite fiber, is a material made up of tiny, crystalline carbon filaments used for reinforcement, making it a chemically stable, corrosion and rust-resistant material. It has the advantage of being lightweight and typically has five times stronger and two times stiffer than steel and aluminum. The strength of carbon fiber makes it an ideal material for racing teams that require strong body parts for their vehicle. When installed, it can endure the high-energy stresses that the vehicle encounters during a race.

However, the expense is undoubtedly one of its disadvantages since it requires more effort and advanced technology to produce carbon fiber. Carbon fiber is also prone to shattering if overtightened or might break if manufactured poorly. Its parts could degrade over time, especially when exposed to sunlight. To avoid long-term damage from sunlight, coat its composites with a UV-resistant coating. Additionally, carbon fiber composites produce galvanic corrosion when in contact with certain metals. More importantly, carbon fiber preserves the vehicle’s structural stiffness and aids in keeping the weight down from the chassis to the body itself. It outperforms metal and other materials in terms of strength and stiffness as a result.
Carbon MonoxideCarbon Monoxide is a colorless, odorless, tasteless, poisonous gas that results from incomplete combustion. It forms when one atom of carbon combines with one atom of oxygen instead of two during combustion. A pollutant is contained and released in the exhaust gas when the fuel burns. This poisonous gas may endanger human health or pollute the environment if improperly handled.
CarburetorA carburetor is a device in an engine fuel system, which mixes fuel with air and supplies the combustible mixture to the intake manifold. In the past, carburetors were part of most fuel systems. However, most vehicles nowadays have a fuel-injection system. As air passes through the carburetor, fuel is drawn out of the float bowl and sprayed into the airstream in carefully measured amounts.
In most engines, a mixture of 14.6 parts air to one part gas ensures maximum vaporization and combustion of the fuel. Hence, the carburetor varies the proportion of fuel and air to suit different operating conditions. For example, a rich mixture of about 9 pounds of air for every pound of gasoline is delivered for starting initial warm-up and accelerating. A relatively lean mixture of about 15 pounds of air for every pound of gasoline is delivered for normal over-the-road operation.
CasterCaster is the angle that the steering axis is offset from the vertical, measured from front to back. If the steering knuckle tilts toward the back, the caster is positive, and if it tilts toward the front, the caster is negative. The tilting of the steering axis forward or backward provides directional steering stability and is aided by a positive caster, while a negative caster makes steering easier. It causes the steering axis to pass through the road surface ahead of the center of tire contact with the road.
It places the push on the steering axis ahead of the road resistance to the tire. The tire trails behind, as the positive caster causes the steering axis to lead or pull the tire and wheel down the road. Additionally, it keeps the wheels pointed straight ahead, which helps overcome any tendency for the vehicle to steer away.
Catalytic ConverterThe catalytic converter, also known as pollution control, is the muffler-like device used in the exhaust system. An active substance called catalyst causes a chemical reaction that turns exhaust emissions into harmless substances. The early catalytic converters contained a platinum-coated ceramic or aluminum-oxide pellet coated with platinum. These convert hydrocarbon and carbon monoxide into water vapor and carbon dioxide.
But this converter needs extra oxygen to properly perform since oxygen is pumped into the exhaust system by an air aspirator valve. On the other hand, new converters are a two-in-one design. The front section is called a three-way catalyst because it controls hydrocarbon, carbon monoxide, and nitric oxide by turning them into water, carbon dioxide, and nitrogen. The rear section is an oxidation catalyst that further reduces hydrocarbon and carbon monoxide.
CCACold Cranking Amp is a battery rating that quantifies how much power it provides to deliver a constant amp output to start the engine at a specific temperature, particularly during the cold-start situation. It is essential in the most automotive application. But the cold-cranking amps drop when the capacity of the battery depletes.
The discharge and recharge cycle occur over the lifespan of a battery. Each cycle wears down the plates slightly, and the lead in the battery deteriorates. As the temperature drops in a cold climate, more power is required to start the vehicle’s engine. The available power can’t start the engine as a result. Thus, it is necessary to have a battery with higher cold cranking amps since it is more dependable and lasts longer, specifically in cold conditions.
CD ChangerCD Changer is an in-dashboard CD player which can read compact disk data that contain songs in popular formats. It is also compatible with any radio that has an FM tuner on the vehicle. It resolves an issue when listening to compact disks on the vehicle’s stereo system by allowing easy switching between CDs with just a push of a button.
Center DifferentialA Center Differential also called the interaxle differential, is a two-position differential located in the driveline or transfer case of some four-wheel-drive vehicles. Its function is to compensate for any difference in front and rear-wheel travel, which allows the front and rear axles to operate at their speeds without forcing wheel slippage during normal driving on dry road surfaces. When total traction is lost at any one wheel, all the torque will be delivered to that wheel, and the vehicle will be immobilized until the driver locks up the transfer case differential through a lever inside the vehicle. On the other hand, traction must be lost at both the front and rear wheel if a limited-slip differential is used in the transfer case to stop the vehicle.
Charcoal CanisterA charcoal Canister, also known as Evaporation Emission Control System, is a container filled with activated charcoal used to trap gasoline vapor from the fuel tank and carburetor while the engine is off. It ensures that harmful gases from the gas tank can’t generate pollution by absorbing fuel vapor that would vent into the atmosphere. The canister’s valve allows trapped vapors back into the engine, which will be burned to power the engine during operation. A defective charcoal canister may result in a low fuel economy. It means that the vehicle will waste gasoline rather than use it efficiently.
Charging SystemThe charging system restores the charge lost in the battery, particularly from cranking the engine. This system also handles the load of the ignition, lights, radio, and other electrical and electronic equipment while the engine is in operation. The charging system includes the alternator with a regulator, battery, and connecting wires. The engine provides the power to move the vehicle, but electricity powers most of the devices in the vehicle during short or long drives. The charging system does not require periodic maintenance except for drive-belt tension and condition.
ChassisChassis refers to a structural frame in which all OEM components are installed. Modern car bodies must be designed to protect the driver and passengers in a crash to provide adequate passenger and luggage space. But the need for fuel economy dictates that cars be lighter and smaller than models of conventional vehicles.
The separate chassis frame once gave a car its structural strength, which provides a platform for mounting its mechanical components. The body was bolted to this frame, which made for a high and heavy but quiet and durable automobile. Recently, cars now have unit-body construction. Stamped sheet-steel parts are welded together to form box structures that work much like the trusses in a bridge to form a light but strong unit.
Check Engine LightCheck Engine Light, also known as Service Engine Soon, is a warning indicator that illuminates on the dash when an issue occurs. Modern vehicles have a 12-pin connector under the instrument panel near the steering column. To read stored codes, turn the ignition key to ON but do not start the engine. Usually, a jumper wire is inserted into the ground and the diagnostic terminal of the diagnostic connector.
The Check Engine or Service Engine Soon light will flash code 12 three times. Then the light will flash each code stored in memory three times, depending on the faults or failures that happened in the vehicle. When there is more than one trouble code, correct the cause of the lowest code first unless directed by the service manual. The technician can retrieve the stored trouble code from the ECM memory. To use the code, the technician finds the chart for that number in the vehicle service manual.
ClearanceClearance, also known as ride height, is the shortest distance between the lower end of the vehicle’s body or chassis and the road. It is one of the vehicle’s fundamental measurements to drive over obstacles such as hills, boulders, and muddy surfaces without sustaining damage. A vehicle with higher ground clearance has greater vertical room to traverse and absorb road shocks but reduces stability and slows down the vehicle’s speed. On the other hand, a vehicle with lower ground clearance performs better at higher speed, but the underbelly may scrape against a pothole and cause damage.
Clock SpringClock Spring refers to a mechanical device containing wound-up wires inside. These wires keep steering wheel buttons, airbags, and horns connected during steering wheel rotations.
ClutchThe clutch or clutch assembly consists of a flywheel, the clutch disc, and the pressure plate, which connects the engine to a manual transmission. Stepping on a foot pedal disengages the clutch disc so that the engine can run without turning the wheels. It allows the driver to shift the transmission gear from one to another.
When the torque transmitted by the clutch is smaller than the torque generated by the engine, the clutch will slip. As a result, the facing of the clutch disc will wear faster. If it is too large, the clutch engagement shock will be large and will tend to cause the engine to stall when the clutch is engaged.
Clutch DiscThe clutch disk, also known as friction disc, is a flat steel disc with a splined hub that slides on the transmission input shaft. A friction material on both sides of the clutch disc, similar to that in brake linings, allows the disc to be engaged gradually for smooth starts. It is also a driven disc about 12 inches or less in diameter that slides back and forth on the shaft splines. Strong springs squeeze the clutch disc between the flywheel and pressure plate to take up the shock engagement. The clutch disc is locked in place, the engine power passes from the flywheel to the clutch disc to the transmission input shaft, driving the vehicle in motion.
Clutch PedalClutch Pedal is a foot-operated lever found on the bottom left of the operational pedals in manual-transmission vehicles. When the pedal is depressed, the piston moves to the left in the clutch cylinder allowing the fluid to flow, which builds up hydraulic pressure. The hydraulic pressure moves the pressure plate back and frees the clutch disc from the flywheel. No engine power can flow through to the transmission or transaxle as a result. This allows the driver to select the proper gear for the operating condition.
When the pedal is released, the piston is pushed back to the right, decreasing the hydraulic pressure. Thus, the clutch engages and allows power to flow through. This provides smooth engagement and lessens the shock on the drivetrain parts. As the engine develops enough torque to overcome the inertia of the vehicle, the drive wheels turn and the vehicle begins to move.
Cold Air IntakeCold Air Intake is a low restriction air filter that brings cooler air into the combustion chamber, providing more horsepower.
Collision InsuranceCollision Insurance is to cover damages caused by a collision.
Combustion ChamberThe roof over each cylinder in an engine forms a combustion chamber. It is the space between the top of the piston and the cylinder head, which the combustion of the compressed air-fuel mixture takes place. The chamber’s shape determines how well the engine will run, what kind of fuel it needs, how much fuel it burns per horsepower produced, and the volume of pollutants that come out of the tailpipe. The shape of the combustion chamber also has a considerable effect on its knock tendencies.
An efficient combustion chamber must meet several requirements. The chamber must be compact to minimize the surface area that absorbs heat when the fuel burns. There should be no nooks or crannies, which can cause spontaneous combustions or knock. The chamber must move large volumes of the air-fuel mixture into the combustion chamber conveniently. Lastly, it must provide available room for the spark plug since the ignition flame spreads across the chamber at a finite speed.
CompositeComposite consists of two or more components, one strong component, and one binding component. The most familiar composite is fiberglass which is a glass fiber that bonds with a plastic matrix.
Comprehensive InsuranceComprehensive Insurance is coverage that helps you repair or replace a vehicle from damages not caused by a collision.
Compression RatioCompression Ratio is the difference between the volume inside a cylinder, which tells how much air-fuel mixture is compressed. To simply put, it is the volume in a cylinder with the piston at Bottom Dead Center divided by its volume with the piston at Top Dead Center. The compression ratio of an engine is an important factor in engine performance. Typically, increasing the compression ratio will increase engine power output.
One important advantage of higher compression ratios is that the air-fuel mixture is more highly compressed at the start of the power stroke. Therefore, higher combustion pressures will be attained as the power stroke begins. Furthermore, the combusting mixture will expand more as the power stroke proceeds. The more the air-fuel mixture can be compressed, the higher the horsepower and fuel economy of an engine. However, higher compression ratios can cause excessive combustion temperature peaks that produce an air pollutant called nitrogen oxide that causes smog.
Compression RingA compression ring is usually made of gray cast iron that holds blow-by to a minimum. This material wears well and at the same time provides sufficient initial ring tension, or pressure, on the cylinder walls. Two or more compression rings keep most of the high-pressure combustion gases from escaping past the piston. If these rings are worn, an excessive amount of gas blows by, reducing the engine power.
Most compression rings are usually coated with certain metals to improve their wearing qualities. It enables the compression ring to make good contact with the cylinder wall around the periphery of the ring. It also makes good side contact with one or the other side of the piston-ring groove around the circumference of the compression ring. Lastly, to have a minimum gap at the ring joint, compatible with safe operation to avoid complete closure of the gap.
Compression StrokeCompression Stroke is a phase of the engine’s cycle in which the fuel-air mixture gets compressed from the bottom of the cylinder and gets pushed upward to the dead-end to ignite the mixture. It is also called a second stroke.
CompressorCompressor, a belt or electric-driven pump, increases refrigerant pressure to cool down the cabin.
CondenserCondensers function as heat exchangers in the air conditioning system of a car. Condensers look very much like radiators, just a little thinner, and they also depend on air flowing through them. They are located in front of the radiator. Nowadays, condensers are often made of aluminum, and in the past, some were made of copper or brass.
Connecting RodConnection Rod is the link connecting the piston to the crankshaft.
ConsoleConsole refers to a space located inside the vehicles. There can be several consoles like the dashboard, in between seats, under the seats, or in the headliner.
Control ArmControl Arm refers to a link that connects the front wheels to the vehicle.
CoolantCoolant refers to an anti-freeze/water mixture used to cool down the engine. Coolant moves heat generated by burning fuel in the engine’s cylinders to the radiator, where the coolant is cooled down. Engine coolant prevents freeze-up in winter, raises the boiling point in summer, and protects the cooling system from rust and corrosion year-round.
Coolant ReservoirCoolant Reservoir is where the excess coolant is stored. As the engine warms up, the fluid will move to the coolant reservoir when the engine cools down and will be drawn back in the radiator.
Cooling FanA Cooling Fan draws cold air inside the engine bay by pulling through the radiator. It is either mechanical, electrical, or hydraulically driven.
Cornering LightsCornering Lights are two amber lights located on the front corners that use aid during cornering. Also known as parking lights.
Counter BalanceCounter Balance is weight added or reduced to a rotating shaft or flywheel to balance to reduce vibration.
Counter ShaftCounter Shaft in the manual gearbox is the shaft that carries the power of the clutch shaft to the driveshaft. It is turning opposite to the gears.
Counter WeightCounterweight refers to a weight added to rotating shafts or wheels to balance and neutralize vibration. These are on the crankshaft, wheels, flywheel, and driveshaft.
CowlCowl refers to a portion between the car body and the engine compartment. Usually, this is the cover that sits under the windshield wipers.
CPOCPO means Certified Pre-Owned vehicles which are closely inspected and have to meet standards to qualify as certified pre-owned vs. a used car. A CPO vehicle often comes with vehicle warranties.
Crank CaseA Crank Case is the lower part of the engine block that encases the crankshaft and its bearings.
Crank ShaftCrank Shaft is essentially the backbone of the internal combustion engine. The Crank Shaft is responsible for the engine’s proper operation, and it converts a linear motion to a rotational motion.
Crankcase BreatherCrankcase Breather is a valve that releases excessive crankcase pressure.
CrankshaftCrankshafts are rotating shafts that are used to convert the reciprocating motion of pistons into rotational motion. Crankshafts are used in internal combustion engines and consist of a series of cranks to which the connecting rods are attached.
Cruise ControlA Cruise Control system automatically controls a vehicle’s speed. This mechanical servo system takes over the throttle to maintain the speed set by the driver.
Crumple ZoneCrumple Zone is the area that collapses during an impact to reduce energy from the collision and avoid bodily injury.
Curb WeightThe Curb Weight is its empty weight without passengers or cargo, resting on a flat surface.
Curtain AirbagsCurtain Airbags are installed on the side of the vehicle. During an impact, it will unfold and protect the occupant’s head and upper body.
Cuts OutCut Out is a loss of power of the engine. The engine could misfire, and it feels like an engine shut off.
CV JointConstant Velocity Joint or CV allows a driveshaft to transmit power through an irregular angle during rotational speed without increased friction or play.
CV Joint BootCV Joint Boots prevent water and debris from entering the joint and contaminating it.
CVTCVT Transmissions have endless gear ratios. The engine runs at a constant speed without having to change gears. The goal is to maximize engine efficiency. A CVT transmission has a longer maintenance interval. The early versions of CVT transmissions had higher failure rates compared to the automatic transmission.
CylinderCylinder refers to the cylindrical shape inside the engine block. It is the surface on which the piston moves and compresses the air-fuel mixture, measured in cm or inches. It is typically cast iron and very smooth and honed so the piston can move without damaging either surface.
Cylinder HeadCylinder Head is an aluminum or iron-casted device which holds the intake manifold, the exhaust manifold, and houses on the valvetrain. Depending on the configuration, it may also house the Camshaft.
D-PillarD-Pillar is the rearmost roof that supports the structure on an SUV, minivan, or wagon.
DampingDamping is used in vehicles to absorb motions on rough surfaces and is usually done on shock absorbers. It also controls oscillations. Heavy-duty trucks and some high-end cars use air suspensions.
DashboardDashboard refers to the panel right under the windshield. It holds gauges and switches and houses the glove box.
dBAdecibels A (dBA) is a measurement unit for sound. It measures the sound’s volume or the signal’s strength, computed as the signal-to-noise ratio.
DC CurrentDirect Current (DC) electricity uses electrons that move in only one direction. Cars operate on 12 volt DC. In contrast to AC’s wave motion, this current moves linearly.
Dead AxleDead Axle is a non-driven axle that is often on the rear of an FWD vehicle.
DecelerationDeceleration refers to the changing velocity of the car during a break.
DEF FluidDiesel Exhaust Fluid (DEF), also called “Aqueous Urea Solution” and in others “AdBlue,” is a transparent, colorless, non-toxic, and virtually odorless liquid that is injected into the post-combustion exhaust stream of a diesel engine to reduce emissions.
DepreciationDepreciation is the loss in value that a vehicle incurs when it is purchased and used.
DetonationDetonation is an explosion of the unburned fuel-air mixture in the combustion chamber that burns from the heat created from the ignited spark. It creates an engine knock which is very stressful for the engine, and it often happens spontaneously.
Diesel Particulate FilterDiesel Particular Filter filters particles from the burned exhaust gases. Those filters need maintenance.
DifferentialDifferential delivers driving force to the wheels while the wheels spin at different speeds due to road conditions. It makes the wheels attached to the suspension act independently.
Digital MultimeterDigital Multimeter is a necessary tool for testing, diagnosing, and troubleshooting electrical circuits, components, and devices.
DipstickDipstick refers to a rod the measures the oil level in vehicles. Those are calibrated specifically to the vehicle and can’t be interchanged with other models. In some cases, dipsticks are used for other fluid applications as well.
Direct Injection SystemDirect Injection is injected directly into the combustion chamber using a fuel injector. A high-temperature injection nozzle is placed for each cylinder.
DSGDirect Shift Gearbox, also called Dual-Clutch Gearbox, is an alternative to automatic transmissions.
DisplacementDisplacement is the volume measurement of the combined cylinders. It is measured when the cylinders are in the downward position.
DistributorDistributor refers to a device that distributes the ignition to each cylinder. Inside the distributor cap is a shaft installed driven by a gear connected to the cam to pass the high voltage created by the coil to each cylinder. The distributor adjusts by increasing acceleration by creating a vacuum.
Distributor capDistributor Cab is over the distributor and its rotor. It has a connector for sparkplug wires. The rotor moves inside the cap and distributes voltage to each cylinder.
DMVDepartment of Motor Vehicles, or DMV, is a state-level agency responsible for vehicle registration and licensing.
DOHCDual Overhead Camshafts is an engine with two camshafts that are usually located in the cylinder head.
Door AjarDoor Ajar Warning Light indicates a door is open. This warning light will come on in red if a door is not securely closed. It will turn off when the door is securely closed.
Drag CoefficientDrag Coefficient (commonly abbreviated as cd, cx, or cw) refers to measuring an object’s resistance or drag in a fluid environment, such as water or air. Any verticle surface adds to the frontal area, so spoilers, wings, and so on add drag.
Drive Axle BootsDrive Axle Boots are made of rubber which holds a grease filling that lubricates the flexible bearings and joints inside the boots.
Drive BeltDrive Belts transfer the rotation of the crankshaft to other devices such as the alternator, air conditioning compressor, and mechanical driver water pumps. A flexible is used for this application and requires regular inspection and replacement according to the User Manual.
Drive Belt TensionerDrive Belt Tensioner refers to a self-adjusting device that keeps the drive belt properly under tension and reduces maintenance costs.
Drive ShaftDrive Shaft is a hollow tube to deliver power and torque to the drive axle or differential. In a vehicle, the drive shaft, also known as the propeller shaft, is used to transfer torque from the engine to parts of the drive that cannot be directly connected to the engine due to distance or other reasons.
DrivelineDriveline refers to the drivetrain minus the transmission, meaning it includes only the driveline components. A vehicle’s driveline is the means by which power is transferred from the engine to the wheels. It is the axels, driveshaft, wheels, joints, and differentials.
DriveshaftDrive Shaft is a hollow tube to deliver power and torque to the drive axle or differential. In a vehicle, the drive shaft, also known as the propeller shaft, is used to transfer torque from the engine to parts of the drive that cannot be directly connected to the engine due to distance or other reasons.
DrivetrainDrivetrain refers to everything from engine output to the wheels meaning the following components: Clutch, gearbox or automatic transmission, universal driveshaft joints, differentials. All the components are creating or transferring torque to the wheels.
Driving LightsDriving Lights are the low beam auxiliary lights that are used in normal traffic.
Drum BrakeDrum Brakes are vehicle brakes in which the brake shoes press against the inside drum of the wheel. Drum brake systems consist of hydraulic wheel cylinders, brake shoes, and a brake drum. When the brake pedal is pressed, the two curved brake shoes, which are lined with friction material, are forced against the rotating brake drum.
DSGDSG stands for Direkt-Schalt-Getriebe, also called Direct Shift Gearbox. One can essentially treat it as two manual gearboxes working alternatively but packed inside one housing. Therefore, it uses two clutches and two gear shafts. A DSG (direct-shift gearbox) is an automatic gearbox with two clutches, which few other automatics have. A dual-clutch gearbox can change gear in just a few hundredths of a second. A dual-clutch transmission (DCT, Volkswagen DSG, Porsche PDK) is a computer-operated manual transmission with two clutches (one for odd gears, one for even gears). If DSG transmission gets too hot: Immediately stop the vehicle and turn off the engine. Let the transmission cool down and consult with your dealership as soon as possible. A low oil level can cause overheating.
Dynamic brake controlDynamic Brake Control is a device that assists in braking in case of an emergency. It is a computer that measures and assists the braking.
E-BrakeE- Brake is a brake that can slow down and hold the vehicle when the hydraulic system fails. It works without having to press the pedal.
E85E85 is the fuel mixture that contains 85% gasoline and 15% Ethanol.
Easy EntryEasy Entry is a system that automatically moves the vehicle’s power seats backward and retracts the steering column to get easier in and out of the cabin.
ECOECO means “Eco Mode,” which stands for the economical mode in the car. Its function is to alter certain features of the engine and transmission to minimize fuel consumption.
ECUECU means Engine Control Unit, which is the brain of the vehicle. It operates the engine and adjusts measured contents, for example, O2 sensors, water, air temperature, and adjusts spark timing. It aims to operate the vehicle as efficiently as possible.
Engine BlockEngine Block contains a cast that holds the crankshaft on the lower part. The cylinder bore is honed and on top of the block where the cylinder head will be installed. It is the heaviest part of the engine.
EFIEFI means Electronic Fuel Injection, which injects fuel into the intake manifold to create the air-fuel mixture. It is easier to control compared to carburetors.
EGREGR, or Exhaust Gas Recirculation, reduces NOx of the exhaust emission by recirculating some of the engine’s exhaust back into the intake manifold. Its purpose is to lower combustion temperature and reduce the emission. Usually, this is done at lower rpm example is cruising or in a traffic jam. It was reported that it leads to carbon build-up inside the engine if a particular operation temperature isn’t reached. Talk to your local mechanic on how to prevent any build-up.
ElectrolyteElectrolyte refers to the mixture of the car battery between water and sulfuric acid.
Emergency BrakeEmergency Brake bypasses the hydraulic brake system on your vehicle, locking the wheels in place. This mechanical system is connected to the emergency brake lever. When engaged in cars with drum brakes, the cables pull another lever that puts pressure on the brake shoes to hold the vehicle. Newer vehicles are equipped with electronic emergency brakes and are activated with the push of a button.
Emergency Brake AssistEmergency Brake Assist is an electronic system that maximizes brake efficiency during an emergency stop.
Emergency Trunk ReleaseEmergency Trunk Release is a handle inside the car which allows you to open the trunk while inside the vehicle. In case of emergency, it can permit to escape through the trunk.
Emission Control SystemEmission Control System limits the amount of gas released from the fuel tank, carburetor, crankcase, and exhaust into the environment.
Emissions StandardsEmission Certification Standard is a numerical standard established by the Environmental Protection Agency (EPA), which the vehicle should not exceed.
EngineEngine refers to the gasoline or electrical assembly which moves either burned energy or electrical energy into mechanical energy.
Engine BlockEngine Block refers to a structure containing the cylinders and other parts of an internal combustion engine.. The cylinder block is the main component of the engine that holds other engine parts attached to it. It has a cylinder cast in it that carries the pistons.
Engine MalfunctionEngine Malfunction can have several causes. Start by reading the fault codes via the diagnostic port under the dashboard or have the vehicle serviced at the dealership.
Engine OilEngine oil is used to lubricate and cool the moving parts of the engine. It protects from corrosion and is required to be changed to be maintained regularly. See the owner’s manual to check the engine oil to be used.
Engine OverheatingEngine Overheating occurs if you do not have enough coolant in your cooling system. Turn off the engine as soon as possible and do not continue to drive to avoid more damage. Let the vehicle cool down before inspecting what could cause the overheating. To assure no further damage get the car towed to the dealership.
Engine ThermostatEngine Thermostat is installed to the engine block and opens at a specific temperature to engage the whole cooling system. A thermostat is very helpful during the winter months to heat first the interior cooling coil for a warm cabin.
Entry LightingEntry Lighting is an indicator that turns on after the car has been unlocked, or the engine has been turned off. It aids passengers when entering or leaving the vehicle.
Environmental ImpactEnvironmental Impact is an assessment of the biophysical effects of a vehicle that has on our environment.
EPSElectronic Power Steering ( EPS ) refers to the modern version of hydraulic power steering and is monitored by a warning light that illuminates during an error.
ESCElectronic Stability Control (ESC) refers to a computerized system for improving vehicle stability.
ESC LightESC Light illuminates and indicates an error. After starting up the vehicle, the ESC light will turn off. In some vehicles, the light illuminates if traction is lost or the road condition is not good. If the light permanently illuminates, contact your dealership to identify the error.
ESPESP (Electronic Stability Program) refers to an electronic system designed to assist the driver in maintaining vehicle control during adverse conditions. The ESP automatically applies the brakes on individual wheels based on your steering and where the vehicle is going. If the ESP light stays on all the time, it means the system is disabled either because you pressed the ESP button or because there is a malfunction. When the light flashes, slow down when you are driving too fast.
EthanolEthanol refers to Ethyl alcohol used as a percentage of fuel.
EVElectric Vehicle (EV) refers to a mode of transport that is powered by electricity. Conventional vehicles use gasoline or diesel engines, but electric cars and trucks use an electric motor powered by batteries or a fuel cell.
EVAP SystemEvaporative Emission (EVAP) control system prevents the escape of fuel vapors from a vehicle’s fuel system. A purge valve opens when the engine is running, allowing a vacuum to pull fuel vapors into the engine. EVAP codes are common and can be a challenge to fix, even for professional mechanics.
Evaporative Control CanisterEvaporative Control Canister refers to a device that captures fuel vapors (hydrocarbons) from a vehicle’s fuel tank so that they don’t escape into the air.
Exhaust EmissionsExhaust Emission is the unburned gases emitted when gasoline gets burned.
Exhaust ManifoldAn Exhaust Manifold is installed on the cylinder head in which the exhaust valves of the cylinder head let free flow to the downpipe and the catalytic converter.
Exhaust PortExhaust Port refers to the way from the exhaust valve to the exhaust manifold.
Exhaust StrokeExhaust Stroke refers to the 4th stroke in a four-cycle engine. It is when the piston moves upwards and pushes outburned exhaust gases.
Exhaust SystemExhaust System is everything from the cylinder head to the muffler of the vehicle. It carries exhaust gases, and it damps noises.
Expansion TankExpansion Tank is similar to a coolant reservoir, except it has a closed system meaning a cap. Usually, Cooling System with Expansion Tank has no filler cap on the radiator itself.
Extended WarrantyExtended Warranty refers to an additional warranty that can be purchased or added by a car dealership when selling a pre-owned vehicle. It extends the manufacturer’s warranty.
External Combustion EngineExternal combustion engines burn fuel outside of the engine. Steam engines are external combustion engines.
Fast idleFast Idle occurs right after starting up a cold engine which lowers itself shortly after, once the car reaches its drivability.
Fault codeFault Code gets stored in a control unit to aid the technician in troubleshooting a vehicle problem.
FenderFender refers to a part that covers the front wheels to prevent mud splattering.
FiberglassFiberglass is a composite material that relies upon and small glass fiber for its strength.
FilterFilters are devices that remove contaminants from foreign particles such as air intake, fuel, or lubrication.
Final Drive RatioFinal Drive Ratio is the ratio measured between the driveshaft and the transmission rate in rpm.
FirewallFirewall refers to the metal sheet installed engine compartment and passenger cabin.
Flex FuelFlex-Fuel refers to an engine that can run depending on its operation different kinds of fuels or even a mixture of several fuels.
FloodingFlooding is to excess fuel filling the cylinders that didn’t ignite, which makes the starting of the engine difficult. Gasoline can be pressured down to the oil pan, which will thin the lubrication oil.
Floor ShiftFloor Shift is a lever installed to the floor pan and often enclosed in a plastic console for automatic transmission or a stick shifter that can be a simple as a rubber boot installed over the mechanical linkage.
FloorboardFloorboard refers to the floor under the instrument panel.
FloorpanFloorplan refers to the biggest part of the car’s body. It is a stamped metal part that contains several smaller attached stampings. It is also called the foundation of the vehicle structure.
FluidsThese usually include the most common: Engine oil, Transmission Oil, coolant, Brake fluid, and hydraulic oil for the power steering. Follow the intervals of replacing those regularly.
FlywheelFlywheels are mounted on engine crankshafts. Its outer part has a gear tooth which allows the starter to rotate it until the engine starts up. The flywheel holds the clutch pack and connects with the transmission to transfer the torque generated by the engine.
FrameFrame is the structure that carries suspension, powertrain, and other components. There are several types of frames, one most common is the ladder frame in SUV’s which had the cabin installed on it. The frame can separate the cabin.
ft-lbFoot-Pound refers to a measurement of work or energy. One foot-pound (ft-lb) is equal to the work done when a force of one pound is exerted on a body that moves a distance of one foot in the direction of the force.
Fuel CapacityFuel Capacity is the amount of fuel that a vehicle’s fuel tank can hold in a fuel tank.
Fuel EconomyThe Fuel Economy of an automobile relates to the distance traveled by a vehicle and the amount of fuel consumed. A consumption rate can be calculated by dividing the amount of fuel used by the distance traveled. Typical units include miles per gallon (MPG) or litters per 100km (l/km).
Fuel FilterFuel Filters are filters installed in series with fuel systems that prevent small debris fragments from reaching injectors and combustion chambers. It prevents particulate matter and most contaminants in the fuel from reaching the engine.
Fuel InjectionFuel Injection is a device that atomizes the fuel by forcibly pumping it through a small nozzle under high pressure and delivering it to the vehicle’s engine. Fuel injectors are responsible for delivering fuel to each cylinder. Most modern vehicles use fuel injectors that spray fuel into the intake manifold or directly into the cylinders. Fuel injection allows for more precise fuel control and improved fuel efficiency. Overall, fuel injectors provide better fuel economy compared to what can be achieved with a carburetor.
Fuel LineFuel Line is the tube that allows fuel to travel from the fuel tank to the carburetor or injector.
Fuel PumpAn Electric Fuel Pumps from the fuel tank to the engine and is typically mounted on top of the fuel tank. A bad fuel pump can prevent the vehicle from starting.
Fuel Pump ShutoffFuel Pump Shutoff is a device that automatically shuts off the fuel pump after an accident.
Fuel TypeFuel Type is used to power a vehicle. The most common type include electric, gasoline, diesel, ethanol, E85, biodiesel, natural gas.
Fuel/Water SeparatorA Fuel/Water Separator refers to a device that separates the water from the fuel as part of the fuel filtration system.
FWDFront-Wheel Drive (FWD) is a vehicle where only the front wheels are active. In such a system, the transmission is connected to the front wheels and not the rear wheels.
Gas GuzzlerGas Guzzler is a federal tax for vehicles with high fuel consumption.
GaugeA Gauge found on the instrument cluster is a device used to display information such as fuel, speed, engine temperature, battery voltage, oil pressure, etc.
Gear OilGear Oil is a heavy-duty lubricant specifically for gears within the differential case.
Gear RatioThe number of revolutions made by a gear compared to the number of revolutions completed by the driven gear. Gear ratios are calculated by dividing output speed by input speed (i=Ws/W) or by dividing the driving gear’s teeth by the driven gear’s teeth.
GearboxGearboxes increase torque while reducing the speed of a prime mover output shaft (e.g., a motor crankshaft). This means that the output shaft of a gearbox rotates at a slower or higher rate than the input shaft, and this speed reduction produces a mechanical advantage, increasing torque.
Glow LightDiesel engine pre-glow the cylinder chambers before the engine starts. The solid lights come on for a few seconds when the ignition is turned on. If the glowing light is flashing, it means there is a malfunction.
Greenhouse GasesGreenhouse gases absorb and emit radiant energy in the thermal infrared range. These gases are responsible for the greenhouse effect on planets.
Ground ClearanceGround Clearance indicates the distance between the lowest point under the car and the ground.
Group NumberGroup Number is a number established by the Battery Council International (BCI) that categorizes a battery based on its length, height, width, and terminal design. The ground number does not define CCA, CA ratings.
GVWRGross Vehicle Weight Rating, known as “GVWR.” It is the total weight of a vehicle’s curb weight, cargo weight capacity, and passenger weight.
Half-ShaftHalf-shaft is used to transmit power from the front (or rear) differential to a wheel.
Head UnitAutomotive head units, sometimes called infotainment systems, control various integrated information systems and entertainment functions via a unified hardware interface.
HeadlightsHeadlight or Headlamp refers to a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also known as headlights, but in the most precise meaning, Headlamp refers to the device itself, while headlight refers to the beam of light produced by the device.
Heads-Up DisplayHeads-Up Display, or HUD, refers to any transparent display that delivers data without requiring the user to look away.
Heat ShieldHeat Shield refers to a device designed to minimize heat transfer that surrounds exhaust components. A heat shield protects an object from overheating by dissipating, reflecting, or simply absorbing heat. The term is most often used about exhaust heat management and to systems for dissipation of heat.
Heater CoreHeater Core refers to a radiator-like device used in heating the cabin of a vehicle. Hot coolant from the vehicle’s engine passes through a winding core tube, a heat exchanger between coolant and cabin air.
HesitationHesitation is a momentary loss of power during acceleration.
High Beam IndicatorHigh Beam Indicator refers to a light on your car’s dashboard that stays on when your headlights are on. In most cars, it will be blue light.
HorsepowerHorsepower refers to a unit of measurement of power, or the rate at which work is done, usually about the output of engines or motors.
HVACHVAC means Heating, Ventilation, and Air Conditioning. With a centralized HVAC system, both warm and cool air can be routed through the same ductwork and controlled by the same thermostat. When a warmer or cooler object is heated or cooled, heat is transferred. Heated and cooled air is produced by a heat pump, despite its name.
HybridHybrid vehicles combine the power of an electric motor and a gasoline or diesel engine.
Hydraulic LifterHydraulic Lifters provide zero clearance when the engine is running, eliminating clatter and periodic adjustments. They do this by applying oil pressure against a spring-loaded plunger inside the lifter body. It pushes the plunger up to take the slack out of the valvetrain and hold it tight.
HydrocarbonsHydrocarbons are organic chemical compounds containing only hydrogen and carbon atoms.
Idle speedIdle Speed is described as when the RPM of the engine with no engine load. Engine speed when the gas pedal is not pressed while the engine is in a park or neutral.
Idler PulleyIdler Pulleys transmit rotation from one shaft to another in applications where it is undesirable to connect them directly. Idler pulleys are also responsible for guiding and tensioning the engine drive belts. The engine drive belts route in a specific manner around the various engine accessories, such as the alternator, water pump, power steering pump, and AC compressor.
Ignition CoilInduction coils in automobile ignition systems convert a battery’s voltage into thousands of volts required to ignite fuel by creating an electric spark in the spark plugs.
Ignition TimingIgnition Timing refers to the process of setting the time of a spark that will occur during the power stroke.
IIHSInsurance Institute for Highway Safety is a nonprofit U. S. organization funded by auto insurance companies that were established in 1959 and headquartered in Arlington, Virginia. Insurance Institute for Highway Safety is an organization created by the insurance industry to reduce the losses of (deaths, injuries, and property damage) from vehicle crashes.
ILEVLow-Emission Vehicle is a vehicle that meets the super ultra-low emission vehicle ( SULEV ) standard for exhaust emissions and the federal inherently low-emission vehicle ( ILEV ) evaporative emission standard. It includes certain zero-emission vehicles (ZEVs).
ImmobilizerImmobilizers are electronic security devices installed on cars that prevent the engine from starting unless the correct transponder key is present. It stops the car from being “hot wired” after entry of the car and thus reduces motor vehicle theft.
Independent SuspensionIndependent suspension refers to any automobile suspension system that allows each wheel on the same axle to move vertically independently.
Induction SystemInduction System refers to the following items: Carburetor or fuel injection system, intake ports, intake manifold, and intake valves.
Inline EngineInline Engines refer to a car engine where all the cylinders are straight rows instead of a V-shape.
Intake ManifoldIntake Manifolds, or Inlet Manifolds, supply the cylinders of an engine with fuel and air mixtures. The flow of air or air-fuel mixture from the throttle body to the cylinder head. The throttle body feeds the plenum chamber, which then feeds individual tubes, called runners, to each intake port.
Intake PortIntake Port is the passageway in a cylinder head that leads from the intake manifold to the intake valve.
Intake StrokeIntake Stroke is the first stroke where the piston moves downwards from the top dead center creating a vacuum and sucking in the air-fuel mixture in the cylinder.
Intake ValveIntake Valve allows the fuel-air mixture to suck inside the cylinder for the first stroke.
IntercoolerIntercooler refers to a heat exchanger that cools the air that has been heated during compression. This application is in Turbo – or Supercharged applications.
IntermittentIntermittent is when a problem or error comes and goes with no obvious observations or warnings.
Internal Combustion EngineInternal Combustion Engine refers to which the air-fuel mixture gets burned.
Jack StandsJack Stand is a secure holding device that secures heavy loads once lifted by a floor jack. These are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons).
Jump StartJump Start is used if the car’s battery is discharged and a charged battery or device gets connected to help start the vehicle by supplying the necessary amps.
Keyless ignitionKeyless Ignition is the push-start ignition in most modern cars. The key fob gives an electronic sensor signal that indicates the vehicle to its identification.
KickdownA kickdown in an automatic transmission is referred to as a downshift by a strongly pressed throttle (gas pedal).
KilometerKilometers are metric units of measurement and equal one thousand meters.
Knee airbagsKnee Airbag is a device installed usually on the driver’s side beside the steering column to deploy in a case of impact to protect the driver’s legs.
Knock SensorKnock Sensor measures the high frequency and vibrations caused by detonations by the engine. It is mounted on the engine and is computerized.
KPHKPH stands for Kilometers per Hour. Kilometers per hour are units of speed, indicating the distance traveled in an hour.
Lane Departure Warning SystemLane Departure Warning Systems alert drivers if their vehicle leaves its lane.
Lane WatchLane Watch is a camera that will show the blind spot on the right side of the vehicle. The blind spot can be seen on the monitor of the vehicle.
Lateral AccelerationSideways acceleration during cornering. Centrifugal force acts on the car and tries to pull it outward to counteract this outward force that the tires have to have an equal and opposite force to keep the vehicle on track.
Leaf SpringLeaf Springs consists of a long, slender length of spring steel with a rectangular cross-section. Leaf Springs can either be attached directly to both ends of the frame or directly at one end, usually the front, and connected to the other end by a shackle, a short swinging arm.
LemonLemon is a vehicle that has numerous or severe defects apparent before its purchase. There is a lemon law that provides owners with certain rights.
LesseeLessee refers to a person that signs a lease for a vehicle. The Lessee is responsible for the car and the vehicle’s payment.
LEVLEV stands for Low Emission Vehicle. A low-emission vehicle emits relatively low levels of motor vehicle emissions.
Li-ionA lithium-ion battery or Li-ion battery (abbreviated as LIB) is a type of rechargeable battery. The batteries have a high energy density, no memory effect (other than LFP cells), and low self-discharge.
Limited warrantyLimited Warranty is the indicated warranty by the manufacturer, usually measured in time and or mileage.
Limited-Slip DifferentialLimited-Slip Differential (LSD) allows its output shafts to spin at different speeds but limits the maximum difference between the two shafts. A lithium-ion battery or Li-ion battery (abbreviated as LIB) is a type of rechargeable battery. The batteries have a high energy density, no memory effect (other than LFP cells), and low self-discharge.
Live AxleLive Axles are beam axles in which the shaft (or, more commonly, several shafts connected as one) also transmits power to the wheels. Contrary, a beam axle that does not transmit power is called a dead axle.
LNGLiquefied Natural Gas (LNG) is natural gas predominantly methane, CH4, with some mixture of ethane, C2H6 that cooled down to liquid form for ease and safety of non-pressurized storage or transport.
Lock CylinderLock Cylinder is when a car can be locked or unlocked by operating a mechanical mechanism.
Locking DifferentialLocking Differential “locks” both wheels on a shaft together as if on a shaft, overcoming the main limitation of a standard open differential. It will force both wheels to turn in unison, regardless of the traction available to either wheel individually.
Low VoltageLow Voltage is when the alternator is not charging correctly in a vehicle. A battery sign will illuminate your dashboard that indicates a charging failure. A red battery sign will show in your dashboard that indicates a charging failure.
LPGLiquid Petroleum Gas (LPG), or Liquefied Petroleum Gas (LPG), is a mixture of hydrocarbon gases commonly used for heating, cooking, and motor vehicles.
Lug NutLug Nuts lock the wheels on the car. These nuts are locked inside the wheel hub.
Luggage CapacityLuggage Capacity is the volume measurement of the vehicle’s cargo trunk.
Lumbar SupportLumbar Support is a part of a vehicle’s seat that supports the back of the driver or passenger. The adjustable lumbar mechanisms allow the user to change the seatback shape to make it more comfortable and include an adjustable lumbar cushion.
MAF SensorA Mass (Air) Flow Sensor (MAF) measures the flow rate of air entering an internal combustion engine. The Engine Control Unit (ECU) must know how much air is in the engine to balance and deliver the correct amount of fuel. If the MAF sensor fails, the check engine light will illuminate.
Main BearingsMain Bearings hold the crankshaft in place and allow it to spin in the engine block. Main bearings are plain bearings or journal bearings held in place by the engine block and bearing caps.
MaintenanceMaintenance refers to the periodic preventive care of the vehicle. Maintenance has to be followed according to the owner’s manual to void the manufacturer’s warranty.
Manual transmissionManual Transmission uses a clutch and manual gear shifter to change the gears within the transmission.
Mass Air Flow SensorA Mass (Air) Flow Sensor (MAF) measures the flow rate of air entering an internal combustion engine. The Engine Control Unit (ECU) must know how much air is in the engine to balance and deliver the correct amount of fuel. If the MAF sensor fails, the check engine light will illuminate.
Master CylinderThe brake master Cylinder acts like a hydraulic pump that is attached to the pedal. It moves and detaches the brake fluid to the caliper and brakes drums for mechanical work. The brake master contains two separate systems that usually work over across in case of failure.
Master CylinderMaster Cylinder converts force (usually from a driver’s foot) into hydraulic pressure. This device controls slave cylinders at the other end of the hydraulic system. When foot pressure is applied to a piston, hydraulic pressure is created to push fluid through lines and wheel cylinders to force brake pads against discs. By pressing the brake pedal, mechanical power is converted into hydraulic power, which slows or stops the vehicle. The brake master cylinder is located in the engine bay near the brake fluid reservoir. The brake fluid reservoir is mounted right above the master cylinder and stores the fluid until needed.
Maximum Cargo CapacityMaximum Cargo Capacity refers to the maximum volume and weight that includes the rear seats folded if applicable.
Memory SettingsMemory Setting refers to a presetting that remains constant in the ECM unless disconnected from a power source. (I.E., the mirrors, seats, radio, and HVAC systems).
Metric SocketsMetric Socket is a tool that attaches to a socket wrench, ratchet, torque wrench, or another turning tool to tighten or loosen a fastener such as a nut or a bolt. Drive Hole indicates the size of the drive hole (also referred to as the “driver hole” or “square hole”), which determines the torque size of the driver tool you’ll need. For example, you would use half-inch drive socket with half-inch drive ratchet.
MILMalfunction Indicator Lamp (MIL) refers to a warning light on the instrument cluster that indicates a malfunction. This warning light indicates almost anything from a loose gas cap to a serious knock in the engine.
Mileage AllowanceMileage Allowance is the number of miles permitted to drive in the term of the lease. Exceeding those can lead to penalties or increased contract costs.
MisfireMisfire is the failure of igniting the air-fuel mix completely. It can cause by several things.
MountMount holds a power train or accessories to a vehicle’s chassis or body.
MPGMiles Per Gallon (MPG) refers to the miles driven dived by the fuel consumed.
MPHMiles Per Hour refers to the speed at the vehicle is traveling at the moment.
MSRPManufacturer’s Suggested Retail Price (MSRP), also known as “sticker price,” is the suggested retail price of a product at which the manufacturer recommends that the retailer sell the product.
MufflerMuffler refers to the last part installed of the vehicle’s exhaust system. It is a chambered muffler that reduces the noise created by the exhaust.
Multi-Point InjectionA Multi-Point Injection system uses a fuel injector for each cylinder.
Multileaf SpringMultileaf Spring is a leaf spring with several leaves bundled together by steel bands.
Multilink SuspensionMulti-link Suspension refers to a suspension design used in independent suspensions, consisting of one or more longitudinal arms and three or more lateral arms. The front suspension consists of one of the lateral arms replaced by the tie-rod that connects the steering rack to the wheel hub.
Natural Gas EngineNatural Gas Engine is internal combustion that burns natural gas. Most vehicles upgrades to this option for better fuel economy.
Navigation SystemNavigation System guides you to a requested location using satellites to help the driver.
NHTSANational Highway Traffic Safety Administration (NHTSA, pronounced “NITZ-ah”) is an agency of the Department of Transportation within the U.S. federal government. The organization’s mission is to “Save lives, prevent injuries, and reduce vehicle-related accidents.”
NightvisionNightvision is an exterior camera that uses infrared technology to provide added visibility when driving in the dark.
NLEVA set of transitional and initially voluntary “national low emission vehicle” (NLEV) standards was used starting in 1999 for northeastern states and 2001 in the rest of the country until Tier II, adopted in 1999, began to be phased in from 2004 onwards.
NmThe newton-meter (also newton meter; symbol N⋅m or N m) is a unit of torque (also called moment) in the SI system. The newton-meter is equal to the torque generated by a force of one newton applied perpendicularly to a moment arm of one-meter length. One pounds-force foot (lb.-ft) equals 1.356 Newton meters. One Newton meter equals 0.7375 lb.-ft.
NOxNitrous oxide refers to a fairly inert oxide of nitrogen that has many uses as an oxidizer for rockets and car engines.
O-RingO-Ring is used in groves to provide sealing. It is a ring form made of rubber.
OBD-IIThe OBD-II standard is a type of diagnostic connector, pinout the electrical signaling protocols available and the messaging format. On-board diagnostic is an automotive term referring to a vehicle’s self-diagnostic and reporting capability. The On-Board Diagnostics Parameter IDs (OBD-II PIDs) are codes used to request data from a vehicle for diagnostic purposes. In North America, all on-road vehicles and trucks sold since 1996 must meet a subset of these codes, primarily for state-mandated emissions inspections.
OctaneOctane is the number that indicates the anti-knock quality of the gasoline.
OdometerOdometer refers to the instrument located in the dashboard to measure the speed driven.
OEMOEM stands for Original Equipment Manufacturing. Usually refers to components used to build the vehicle at the factory and available for service replacement through franchised dealers.
OHVOver-Head valve (OHV) is positioned directly above the piston in a valve-in-head engine.
Oil FilterOil Filters work by filtering dirt and debris from engine oil as it is being lubricated.
Oil Level LowOil Level Low indicates that there might be somewhere an oil loss. Regularly check the oil level.
Oil LightOil Light indicates a low oil level. After starting the engine, it should turn off right after, and if the oil level is low, the light will turn on. Turn the engine off asap to avoid damage. Check the oil level and top up so that the oil level is in order. Bring the vehicle to the dealership to see if there might be leakage.
Oil PanOil Pan refers to the lowest part of the engine block. It is attached to the engine block and can be detached from the engine block. It serves as a reservoir for engine oil.
Oil Pressure WarningOil Pressure Warning means that your engine has excessive or low oil pressure. The problem can be caused by a blocked filter, a blocked oil gallery, or the wrong grade of oil. Low oil pressure indicates worn bearings or a faulty oil pump. Low oil pressure can trigger a warning light on some vehicle engines. Stop – no oil pressure, turn the engine OFF. See owner’s manual.
Oil PumpOil Pump is an engine-driven pump installed inside the oil pan to pump oil to the moving engine parts.
One-touch WindowsOne-touch Window switches are configured to raise or lower the window glass with one touch.
OverdriveOverdrive refers to the highest gear in the transmission. It allows the engine to operate at a lower RPM for a given road speed. It will enable the vehicle to achieve better fuel efficiency and often quieter operation on the highway.
Overhead CamOverhead Camera is a camshaft installed above the cylinder head instead of inside of the engine block.
Overhead ValveOverhead Valves are in which the valves are installed directly over the pistons.
Overpressure Safety SwitchPressure Relief Valve (PRV) refers to a type of safety valve that controls or limits the pressure in a system; otherwise, it could build up. A switch will be an example on a turbocharged engine that will warn the operator of excessive pressure and may cause a malfunction.
OversteerOversteer refers to when a car turns more than the steering direction of the driver.
Oxygen SensorOxygen Sensor, also called the O2 sensor is an input sensor that reports to the ECU. It gives feedback and the air-fuel mixture burned by the engine. Usually, the exhaust system has two sensors. One is installed before the one installed after the catalytic converter. The O2 sensors are also responsible for the fuel economy of the car.
Parking AssistParking Assist refers to an automated parking aid that helps the driver park very well using guidance system technology.
Parking BrakeParking Brakes, also known as emergency brakes (e-brakes), are mechanisms that keep a vehicle in place.
Parking LightsParking Lights are used once the light switch moves to the first stage. In modern cars, this is also referred to as daylight running light. It increases the visibility of the vehicle.
Parking SensorsParking Sensors are installed in the rear and front bumpers to measure the distance to nearby cars or objects while parking in a spot. The driver gets warned by a sound or light.
Particulate FilterDiesel Particulate Filter (DPF) catches and stores exhaust soot (some refer to them as soot traps) to decrease emissions from diesel cars. Due to their limited capacity, this trapped soot needs to be periodically removed or burned off to regenerate the diesel particulate filter.
PayloadPayload Capacity refers to how much weight a vehicle can carry inside its cabin or truck bed. Anything you put inside your vehicle, whether the cargo or passengers, counts towards the vehicle’s payload.
PCVPositive Crankcase Ventilation (PCV) system removes harmful gases from the engine’s crankcase and burns those gases in the cylinders. Positive crankcase ventilation devices allow the venting of combustion gases from the crankcase to the intake system instead of into the atmosphere.
Penetrating OilPenetrating Oil, known as penetrating fluid, is a very low-viscosity oil that can free rusted mechanical parts to remove them.
PetroleumPetroleum is a naturally occurring, yellowish-black liquid that forms underneath the Earth’s surface. A complex mixture of hydrocarbons and small amounts of other elements occurring in nature as deposits of decomposed organic matter.
PillarPillars refer to the vertical or near-vertical pillars supporting the windshield or the car’s greenhouse, referred to as the A, B, C, or (in larger cars) D-pillars, from front to rear.
Pilot BearingPilot Bearings are located between the engine and clutch and allow the transmission shaft to rotate at a different speed than the crankshaft. By the main bearings, the shaft is suspended and splits towards the input end. A pilot bearing holds the shafts together at the point of the split.
PistonPiston refers to a component of reciprocating engines, reciprocating pumps, gas compressors, and pneumatic cylinders, among other similar mechanisms. It is the moving component that contains a cylinder and is made gas-tight by piston rings.
Plenum ChamberPlenum Chamber is a portion of the intake manifold system on an engine that delivers air. The chamber is in between the throttle body and the runners of an intake manifold.
Pound-FeetPound-Feet are the units of measurement for torque. Force is produced when a one-pound force is applied to the end of a one-foot-long lever.
Power LossPower Loss is referred to the engine’s runs and reduced speed while the throttle is held constantly.
Power SteeringPower Steering is a system that uses hydraulic fluid or electrical assistance to reduce the driver’s efforts in using the steering wheel at lower speeds. Once the speed increase, the Power Steering system adapts to it.
Power Steering FluidPower Steering Fluid is often called ATF 9 automatic transmission fluid, and its color is red.
PowertrainPowertrain refers to engine, transmission, driveshaft, differential, and axles to deliver power to the wheels.
PSIPounds per Square Inch (PSI) refers to a standard measurement of pressure.
PulleyPulley refers to a rotating driven device that holds the drive belt.
Purge ValvePurge Valves are part of the vehicle’s Evaporative Emission Control (EVAP) system. The system stops fuel vapors in the fuel tank from escaping into the atmosphere. The EVAP system holds fuel vapors from the fuel tank and temporarily stores them in the charcoal canister.
PushrodPushrod refers to a metal rod to operate valves in a cylinder head in which the camshaft is attached in the engine block.
PZEVPartial Zero Emission Vehicles (PZEV) are environmentally friendly automobiles that comply with strict standards.
Rack and PinionRack and Pinion means a horizontal rack (= flat-toothed bar) engages a horizontal pinion on the steering column. It refers to a linear actuator that comprises a circular gear (the pinion) engaging a linear gear (the rack), which translates rotational motion into linear motion. Driving the pinion into rotation causes the rack to be driven linearly.
RadiatorRadiator refers to a cooling system that works as a heat exchanger by circulating hot coolant through the engine by getting it circulated by the water pump.
Radiator CoreRadiator Core is an ahead exchange that heats the inside of the cabin. It is part of the vehicle’s cooling system.
Radiator HosesRadiator Hoses are the flexible rubber connections between the engine radiator, radiator core, and other cooling system components.
RatchetRatchet refers to a tool or mechanical device that allows continuous rotary or linear motion in the opposite direction.
Rear DefrosterRear Defroster is used during winter months that melts ice or removes condensation from the rear window.
Rear SpoilerRear Spoilers help change airflows above, underneath, and around the vehicle. It also reduces wind resistance.
RecallRecall refers to a safety-related bulletin that requires the vehicle to get to the dealership for modifications. The recall must be done with no charge to the consumer. Recall notices are usually sent by mail and are regulated by EPA and DOT.
RedlineRedline is when the engine cuts off its acceleration once the maximum rpm is achieved. It is to protect the engine from several damages. The redline is usually red, or some have a red light that illuminates once it is completed.
RefrigerantRefrigerant is the chemical used in the Aircondition system of the car. It cools down the cabin if the air conditioner is activated.
RimRim is the metal assembly that holds the tire and is also attached to the wheel hub.
Roll BarRoll Bar is tubular steel installed behind and above the driver to protect the car rolls over.
Roll CageRoll Cage is an application often used in race cars. It is tubular steel installed behind and above the driver to protect in case the vehicle rolls over.
Roof RackRoof Racks are large metal or plastic constructions that attach to a vehicle’s roof and carry cargo or bicycles.
Roof SpoilerRoof Spoiler is installed to create downforce during high speeds in high-end applications.
RooflineRoofline refers to the outline or shape of the roof.
Rotary EngineRotary Engine refers to an early internal combustion engine designed with an odd number of cylinders per row radial configuration. The crankshaft is still stationary in operation, with the entire crankcase and its attached cylinders rotating around it as a unit.
RotorBrake Rotor, often referred to as a Brake disc, is a disc-shaped device that rotates with the wheels. Brake pads installed on a brake caliper press against it depending on the brake pedal’s vacuum hydraulic pressure.
RotorRotor or Brake Disc is the rotating part of a wheel’s disc brake assembly, against which the brake pads apply. It is typically made of gray iron, a form of cast iron. Some discs are both drilled and slotted.
Rough IdleRough Idle refers to a vibrating and shaking engine when pressing the gas pedal.
RPMRevolutions Per Minute (RPM) refers to the revolution per minute in which the crankshaft turns.
Run FlatRun-flat refers to tires that can be driven temporarily after losing tire pressure.
Running BoardsRunning Boards are metal boards installed on tall vehicles to aid passengers in entering tall vehicles.
RWDRear-Wheel Drive or RWD is a drive system that applies its motion to the rear wheels. means rear-wheel drive, a drive system that applies its motion to the rear wheels.
SAESAE International, or Society of Automotive Engineers, is an active association of engineers in various fields and a standard-setting organization.
SalvageSalvage is used in the automotive industry to describe a vehicle that has been damaged more than 70% of its market value. Insurance company’s write off those vehicles since the repair cost is too high. Repaired vehicles will be a Rebuild Salvage Title after meeting certain criteria.
SCRSelective Catalytic Reduction (SCR) refers to reducing Nitrogen Oxides (NOx) in diesel exhaust.
Seat Belt RetractorA Seat Belt Retractor refers to a mechanism the moves your seat belt out of the way when you un-buckle.
Seat beltsSeat Belts are harnesses used to secure occupants of vehicles during collisions.
Seat ExtensionSeat Extension refers to a metal rail installed to the vehicle’s seat to extend legroom for a very tall person.
Self-leveling HeadlightsSelf-leveling Headlights are adjusting to the vehicle’s load the correct light settings. It is working automatically by the suspensions height sensors.
SensorSensors are devices that generate a signal that reports a value to the computer.
Serpentine BeltSerpentine Belt is a ribbed belt that drives the engine’s accessory. It usually drives an alternator, water pump, and air conditioner compressor. It is wrapped around several rollers and drive pulleys which gives its name.
Service Reminder LightService Reminder Light illuminates once the vehicle needs general maintenance.
Shift InterlockShift Interlock is a safety feature that prevents drivers from shifting out of the park while not pressing the brake pedal.
Shift LockShift Lock may display on the dashboard reminding the driver to press the brake pedal to start the vehicle or shift it into Drive or Reverse.
Shock AbsorberShock Absorbers or Dampers refer to a mechanical or hydraulic device designed to absorb and damp shock impulses.
Side AirbagsSide Airbags refer to small airbags that deploy during an impact to protect the passenger’s ribcage.
SidewallSidewall refers to the tire. It indicates the information about the tire size, manufacturing dates, grades, ratings, and brand.
Skid PlateSkid Plate refers to an abrasion-resistant material that protects the underside of a vehicle or boat from damage when it makes contact with the ground. In off-road vehicles, motorcycles, and lowered vehicles, skid plates prevent damage to the parts underneath.
SLS FilterSodium Lauryl Sulfate (SLS) Filters remove contaminants from hydraulic fluid in a self-leveling suspension system.
SluggishSluggish means a vehicle does not accelerate smoothly.
SMGSequential Manual Gearbox (SMG) refers to an automated manual transmission without a clutch pedal.
SOHCSingle Overhead Camshaft (SOHC) engines have a single camshaft per bank of cylinders. Dual Over Head Camshaft (DOHC, also known as “twin-cam.”) engines have two camshafts per bank. The first production car that used a DOHC engine was built in 1910.
SolenoidSolenoid refers to a coil of wire used in inductors, electromagnets, antennas, valves, etc. The application of a solenoid varies in many different types of industries. It can be a simple locking device, an automotive gearbox, and an air conditioning unit.
Spark PlugSpark Plug is installed inside the cylinder head to ignite the fuel/air mixture in the combustion chamber.
Specific GravitySpecific Gravity (SG) is a case of relative density. It defines the ratio of the density of a given substance to the density of water (H2O). Substances with a specific gravity greater than one are heavier than water, and those with less than one are lighter than water.
SpeedometerSpeedometers display the speed at which a vehicle is traveling.
SpoilerSpoiler refers to an automotive aerodynamic device whose intended design function is to ‘spoil’ unfavorable air movement across the vehicle’s body in motion, usually described as turbulence or drag. Often, spoilers are mistakenly used interchangeably with wings.
SprocketSprocket refers to a rotating toothed drive driven by a chain.
SRS LightSupplemental Restraint System (SRS) refers to the airbag system, an acronym for Supplemental Restraint System. The SRS light illuminates when the vehicle first starts. It scans the system performance and turns off right after the scan. If the light continuously illuminates, it indicates an error in the system. Contact your dealership to get the vehicle scanned to see the cause of the error.
Stability ControlElectronic stability control (ESC), also called as Electronic Stability Program (ESP) or Dynamic Stability Control (DSC), improves vehicle stability by detecting and reducing vehicle skidding. Some ESC systems also reduce engine power until control is regained.
Stabilizer BarStabilizer Bars (Roll bars, Anti-Sway Bars, Sway Bars, Anti-Roll Bars) are part of many automobile suspensions that minimize body roll when cornering fast or going over uneven roads. It connects opposite (left/right) wheels through short lever arms linked by a torsion spring.
Steering Column LockSteering Column Lock refers to a lock that lets the steering wheel move unless the ignition switch moves from locked to unlock.
Steering DamperSteering Damper is a shock absorber attached to the steering linkage intended to reduce the abrupt snap back of the steering wheel.
Steering KnuckleSteering Knuckles are attached to suspension and steering components and hold wheel hubs or spindles. It is variously called a steering knuckle, spindle, upright, or hub as well. The wheel assembly is attached to the knuckle at its center point.
Steering RackSteering Rack refers to the device that transfers steering wheel movement to the front wheels of an automobile.
Steering Wheel ControlsSteering Wheel Controls are the buttons mounted on the steering wheel that control sound volume, Bluetooth, entertainment, cruise control, telematics, and/or climate control systems.
StrokeStroke is the distance of the piston travel from the dead center bottom to the top dead center.
StrutStrut is the suspension part of the house’s shock absorber and coil spring. Struts are used primarily on front-drive vehicles.
SumpSump refers to the space in the oil pan under the crankshaft that holds the oil like a sump.
Sun SensorSun Sensor helps create and maintain the temperature within the car. It is located at the dashboard behind the windshield, and it measures the infrared part of the direct sunlight.
SunroofSunroof refers to the panel on the top of the car that can be closed or opened. Sunroofs are made to provide proper ventilation to the cabin and let the light come in for enhanced ambiance.
SunshadeSunshade refers to a retractable device the can limit the sunlight from passing through the vehicle’s windshield.
SuperchargerSuperchargers are air compressors that force pressure into the cylinder to increase the engine’s performance. It is belt or chain-driven. The advantage of a turbocharger is that the power output is very linear.
SuspensionSuspension is a system of tires, shock absorbers, springs, air tires, and linkages that connect to the vehicle’s wheels that allow relative motion between the wheels. It supports the road handling, road holding, and ride quality of the vehicle.
Sway BarSway Bar is a part of the vehicle’s suspension that includes the wheels, tires, shocks, steering system, bushing, joints, and linkages. It helps the riding handle turns and prevents the body lean while driving.
T-topT-top refers to a vehicle roof that can be removed. It is installed in between the A and B pillars.
TachometerTachometer refers to an instrument that tells the driver how fast the engine is rotating, and it is indicated in RPM.
Tail lightsTail lights refer to the housing in the rear, which includes vehicles brake lamps, lamps, reverse lights, and signal lights.
Technical Service BulletinTechnical Service Bulletins or TSBs are document procedures for repairing vehicles issued by a vehicle manufacturer when several occurrences of an unanticipated problem occur.
Temperature Warning LightTemperature Warning Light in the dashboard illuminates after turning on the vehicle’s ignition and turns off once the engine starts up. If the light is illuminated during the operation, turn off the engine and get the car inspected by your dealership or mechanic.
ThermostatA Thermostat is a valve installed in the engine block. It regulates the engine temperature. The thermostat allows the heating coil to heat up first to have a more comfortable cabin during cold weather. Once a certain temperature is achieved, the thermostat will open up to assist the cooling system in the engine.
Throttle BodyA Throttle Body is between the air intake and the air cleaner. It contains a valve that regulates the airflow through the intake manifold.
Throttle Position SensorThrottle Position Sensors (TPS) monitor the air intake of an engine. The sensor is usually located on the butterfly spindle/shaft to directly monitor the position of the throttle. TPS is accelerator pedal sensors, which often include a wide-open throttle (WOT) sensor.
Thrust BearingThrust Bearing supports the axial thrust of horizontal and vertical shafts. It prevents the shaft from drifting in the axial direction and helps transfer thrust loads applied on the shaft.
Tie RodTie Rod is a steering component that links the left and proper motion of the front wheels. It connects to the steering arm.
Timing BeltTiming Belt refers to driving the camshaft from the crankshaft. It is a flexible toothed belt that detaches from driving the camshaft. It starts the water pump and requires maintenance. See the owner manual for the interval.
Timing Belt TensionerTiming Belt Tensioner is a roller that holds the timing belt to the correct tightness. It prevents the timing belt from skipping, which could lead to engine failure.
Timing ChainTiming chains are similar to timing belts, which drive the camshaft from the crankshaft. It is nearly maintenance-free.
Tire inflatorTire Inflators are particular types of air compressors used for inflating tires on cars.
Tire load indexTire Load Index is a numerical code that specifies the maximum load (mass or weight) each tire can carry.
Tire prefixTire Prefix is an alphabetic value assigned by the tire manufacturer to indicate its use.
Tire profileTire Profile is a value of the tire’s height and width indicated by the vehicle’s manufacturer.
Tire sizeTire Size is the displayed information on the sidewall of the tire.
Tire speed ratingTire Speed Rating is an alphanumeric value indicated by the tire manufacturer for determining the maximum of the tire to sustain for a while.
Tire treadTire Tread or Track refers to the rubber on its circumference that contacts the road or the ground. As tires are used, the tread is worn off, limiting its effectiveness in providing traction. A worn tire can often be retreaded.
Toe-InToe in, or positive toeing, is when the front of the wheel points towards the vehicle’s centerline.
Tonneau CoverTonneau Covers are hard or soft covers that span the back of a pickup truck to provide protection for the payload or improve aerodynamics.
TorqueTorque is equal to the force applied to a lever multiplied by its distance from its fulcrum and again multiplied by the sine of the angle created. Usually measured in lb.-ft and differs from work or power in that torque does not necessarily produce motion.
Torque ConverterTorque Converter refers to a fluid coupling that transfers rotating power from a prime mover to a rotating driven load like an internal combustion engine. It is between the engine’s flexplate and the transmission. The equivalent in a manual transmission would be the mechanical clutch. It transfers engine torque to the transmission input shaft. The engine drives an impeller, which propels fluid against the vanes of a turbine connected to the automobile’s driveshaft through transmission gears.
Torque SteerTorque Steer is the unplanned influence of engine torque on the steering, especially in front-wheel-drive vehicles. During heavy acceleration, steering may pull to one side, which may be disturbing to the driver. Torque steer is distinct from steering kickback.
Torque WrenchA Torque Wrench refers to a tool for applying specific torque to a fastener such as a nut or a bolt. Usually, it takes the form of a socket wrench with internal mechanisms. It allows the operator to set the torque applied to the fastener to be matched to the specifications for a particular application.
Torsion BarTorsion Bar Suspension (Torsion Spring Suspension) is a suspension that uses a torsion bar as its main weight-bearing spring. As the wheel rotates vertically, the bar twists around its axis and resists the bar’s torsion.
Tow hooksTow Hooks are metal hooks attached to the vehicle’s frame.
Towing capacityTowing capacity is a measurement of how much a vehicle can tow.
TPMSTire Pressuring Monitoring System (TPMS) is designed to check or monitor the air pressure inside the vehicle’s tire.
TRACSA Traction Control System suppresses the spinning of the wheels while driving, which can occur on slippery roads during excessive acceleration. It improves the acceleration performance and the stability of the car.
Traction ControlTraction Control allows maximum traction under acceleration without spinning the wheels. It is implemented with an electronic limited-slip differential and other computerized controls of the engine and transmission.
Trailer hitchTrailer Hitch refers to a tow hitch (or tow bar) that is a part of the vehicle attached to the vehicle’s chassis for towing.
Trailing ArmA Trailing Arm refers to a piece of the suspension system that connects the vehicle’s axle to its chassis. These are rubber components that reduce friction between the suspension parts.
TransaxleTransaxle refers to a mechanical device that merges the functions of an automobile’s transmission, axle, and differential into one integrated assembly. Both manual and automatic versions are available.
Transfer CaseTransfer Case is a piece of the drivetrain of four-wheel-drive, all-wheel-drive, and other multiple powered axle vehicles. The transfer case transports power from the transmission to the front and rear axles using drive shafts. Typically it is used with AWD and 4WD vehicles.
Transfer case fluidTransfer Case Fluid is a lubricant used in the transfer case.
TransmissionTransmission refers to a drive unit which is delivering the engine’s torque to the driving wheels. The transmission provides different ratios to select on how will deliver the torque to the wheels.
Transmission filterTransmission Filter is a component installed in most automatic transmissions. A transmission filter is inside the transmissions oil pan that filters debris and contaminants and prevents those from circulating in the oil. Excessive debris and contaminations can reduce the life of the transmission. Instead of a disposable filter, some transmissions use a reusable metal or nylon mesh screen.
Transmission overdriveOverdrive refers to the highest gear in the transmission. Overdrive allows the engine to operate at a lower RPM for a given road speed. With it, the vehicle can often achieve better fuel efficiency and operate more quietly on the highway.
Transverse engineOverdrive refers to the highest gear in the transmission. Overdrive allows the engine to operate at a lower RPM for a given road speed. With it, the vehicle can often achieve better fuel efficiency and operate more quietly on the highway.
TrimTrim levels indicate what equipment is included with a certain model of car. Trim may also refer to the interior or exterior metal or plastic molding and other decorative additions. The trim level with the fewest features or equipment is called the “base model,” The trim level with the most is called a “fully loaded” model.
Trip computerTrip Computer refers to a computer suited to some cars; most modern trip computers calculate, record, and display the distance traveled, the average fuel consumption, the average speed, and real-time fuel consumption.
TSBTechnical Service Bulletins or TSBs is a documented procedure on how to repair vehicles. The manufacturer issues one when several unanticipated problems occur. Dealers are not required, however, to bring in cars for which TSBs have been issued. Dealers are not required to call in cars for which TSBs have been issued for repairs.
Tune UpTune-Up refers to a series of maintenance procedures (such as replacing spark plugs, filter, checking fluids, flush fluids, changing engine oil, etc.) carried out at a set time interval or after the vehicle has traveled a certain distance. The service intervals specify the vehicle manufacturer in a service schedule. Some modern cars display the due date for the next service electronically on the instrument panel. A tune-up should not be confused with engine tuning, which is the modifying of an engine to perform better than the original specification rather than using maintenance to keep the engine running as it should.
Turbo ChargerTurbochargers, also called turbos, are turbine-powered devices that boost the power and efficiency of internal combustion engines. It is most often used with Otto cycle and Diesel cycle internal combustion engines.
Turbo LagTurbocharger lag, known as turbo lag, is needed to change power output in reply to a throttle change. When accelerating compared to a naturally aspirated engine, there is a hesitation or slowed throttle response.
U-jointUniversal Joint, or U-Joint, is a coupling or a joint connected to stiff rods whose axes are inclined to each other. Typically, these are used in shafts that transmit rotary motion.
ULEVUltra-Low Emission Vehicle (ULEV) refers to a motor vehicle that emits extremely low motor vehicle emissions compared to other vehicles.
UnderbodyUnderbody refers to the underside that sits closest to the road of your car.
UndercarriageUndercarriage is a part of a moving vehicle below the car’s main body. The lower part of the vehicle is typically not visible from above and is parallel to the road.
Understeer and oversteerUndersteer and oversteer are dynamic terms used to indicate a vehicle’s sensitivity to steering. Oversteer occurs when a car turns (steers) by more than the amount commanded by the driver. On the other side, understeer occurs when a vehicle steers shorter than the amount driven by the driver.
Universal JointUniversal Joint, or U-Joint, is a coupling or a joint connected to stiff rods whose axes are inclined to each other. Typically, these are used in shafts that transmit rotary motion.
V-BeltV-belts ( style V-belts, vee belts, or, less commonly, wedge rope) are the most common type of drive belt used on engines to transmit power. It eliminates the slippage and alignment problem and is now the most common belt type for power transmission. They transfer power from a primary pulley to one or more pulleys or driven units. They provide good speed transfer, load distribution, and service life.
Vacuum hoseVacuum Hose, which can also be a “line” or a “tube,” refers to a flexible rubber connection that routes manifold vacuum to various components and accessories. Since the vacuum powers everything from a vacuum brake booster to a windshield wiper motor, a vehicle often contains a number of these hoses.
Valve clearanceValve Clearance refers to the distance or gap between the cam and the top of the valve. It is also known the maximum amount of space between a rocker arm or cam and the valve.
Valve LashValve lash is a measurement of the distance between the rocker arm and the valve stem when the valve lifter is sitting on the base circle of the cam lobe (when the valve is intended to be fully closed).
Valve LifterValve Lifters mostly have an oil-lubricated hardened face that slides on the cam lobe. The cylindrically shaped component presses against the camshaft’s lobe and moves up and down as the cam lobe rotates.
ValvesValves are devices or natural objects that regulate, direct or control the flow of fluids by opening, closing, or partially blocking various passageways. For example, valves open and close a cycle in an engine allowing the ingress of air and fuel into the cylinders.
Valves per cylinderValves per Cylinder is the total number of intake and exhaust valves for each cylinder of an engine.
ValvetrainValvetrain includes the camshaft(s) and the various parts that convert the camshaft’s rotary motion into reciprocating movement at the valves.
Variable Valve TimingVariable Valve Timing is an engine that allows the lift, timing of the engine’s valves to be adjusted for best engine performance.
VINVehicle Identification Number (VIN) is a number or code denoting specific information about each vehicle. A Vehicle Identification Number is a code assigned to an individual vehicle by the manufacturer that distinguishes it from other vehicles. No two vehicles can have a matching VIN. The VIN is stamped into a plate or printed on a sticker and affixed in several places, including inside the engine bay and at the driver’s side door jamb.
ViscosityViscosity refers to the capability of a liquid to flow. An oil with high viscosity is very thick and flows slowly, while oil with low viscosity flows easily. The thickness of a fluid is a measure of its resistance to deformation at a given rate. The viscosity of liquids corresponds to the informal concept of “thickness”: for example, 20W-40 oil has a higher viscosity than 0W-30.
Viscous CouplingViscous Coupling is a mechanical device that transfers torque and rotation by the medium of a viscous fluid. Viscous couplings transfer speed difference from input to output shaft.
VVTVariable Valve Timing is an engine that allows the lift, timing of the engine’s valves to be adjusted for best engine performance.
Washer fluid lightWasher Fluid Light is a light on the cluster that means the windshield washer fluid reservoir is low.
Washer fluid lowWasher Fluid Low means the windshield washer fluid reservoir is low. Add windshield washer fluid by opening the hood and locating the windshield washer fluid tank in the engine bay.
Waste GateWaste Gate is a valve that limits the boost developed in a turbocharger. A wastegate operates by allowing the engine’s exhaust flow to bypass the turbocharger’s turbine section under certain conditions.
Water PumpWater Pumps circulate engine coolant through the engine and radiator. Water pumps are typically centrifugal and use an impeller that generates the coolant to be thrown outside, which causes the coolant to move through the engine. A pump is mounted at the front of the engine and driven by a belt or, it can be electrical. The pump circulates coolant/antifreeze through the engine, radiator, and heater with the main purpose of cooling down the engine.
Water Pump Weep HoleWater Pump Peed Hole is a small orifice on a water pump below the exposed end of the shaft. The small orifice allows the engine coolant to pass externally from a water pump seal when the seal fails.
WattsWatt is a unit of power. In cars, it measures the amount of power that an amplifier or radio can produce or the powered speaker is capable of handling.
Wheel AlignmentAlignment is to put the tires at the correct angle on the asphalt. Alignment ensures reduced tire wear and increases the lifespan of the tires. Before doing alignment, inspect the tires for wear. Uneven wear could indicate a worn-out front suspension or bushings.
Wheel alignmentWheel Alignment is the adjustment of steering components to preset specifications for camber, caster, toe-in, and toe-out.
Wheel bearingsWheel Bearing refers to a crucial for the proper function of the wheel assemblies to work. It allows almost friction-free rotation of the axle and thereby provides smooth tire and wheel rotation.
Wheel coversWheel Cover is a plastic wheel cover on a steel wheel that covers lug nuts or hubs from view.
Wheel locksWheel Locks are lug nuts that will prevent wheel theft. It can only be installed or removed with a specific wrench or key.
Wheel offsetWheel Offset measures how far the wheel centerline is from the hub mounting surface. It measures in millimeters and results in positive, negative, and zero offsets. A positive wheel offset is a hub-mount surface towards the front (or outside) of the centerline, and a negative wheel offset means the hub-mount surface is towards the back (behind) of the centerline.
WheelbaseWheelbase refers to the space between the centers of the front and rear wheels. For road vehicles with more than two axles, the wheelbase is the space between the steering axle and the center point of the driving axle group.
Wiring harnessWire Harness (Cable Harness, Wiring Harness, Cable Assembly, Wiring Assembly, or Wiring Loom) is an assembly of electrical wires or cables which transfer signals or electrical power to any part of the vehicle.
YawYaw-Rate Sensor is a gyroscopic device that calculates a vehicle’s yaw rate. The yaw rate is the angular velocity around its vertical axis. The angle between the vehicle’s heading and speed is called the slip angle related to the yaw rate.
ZEVZero-Emission Vehicle (ZEV) is a restrictive emissions standard.
Philips screwdriverPhilips Screwdriver is a tool that has a slot in its top that looks like a cross and removes a cross or double-slot screw.
Flat-head screwdriverFlat-Head Screwdriver is a tool that has a flat wedge-shaped tip and removes flat-head screws or countersunk screws.
OverheatingOverheating is when the engine is running too hot. A stuck thermostat, blown head gasket or too little antifreeze can cause this problem. If the antifreeze is leaking or not circulating through the radiator it will lead to the engine overheating. If the engine is overheating, pull over immediately, turn off the engine and allow it to cool down. Continuing to drive a vehicle that is overheating can lead to severe engine damage.

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