Hyundai Check Engine Light on

Hyundai Check Engine Light

Last Updated on Tuesday Apr 10, 2018

Hyundai is one of the most reliable car manufacturers out there. The fact of the matter is however that even Hyundai cars can turn on the Check Engine Light (CEL) if there is an engine or emissions problem. If your Hyundai check engine light turned on don't panic. We will show you how to use a Level 1 OBD-2 Scanner some of which cost as little as $20, to read and clear Hyundai check engine light. You may be surprised, but the check engine light may come on for something as simple as the gas cap being loose.

Hyundai check engine light can be triggered for several reasons which we discuss in this guide. 

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1. Why is my Hyundai Check Engine Light on? 

In a Hyundai, the check engine light comes on as soon as the onboard diagnostic system (OBD) detects that there’s an issue with the way the engine operates or Evaporative Emission Control System (EVAP) which is used to prevent gasoline vapors from escaping into the atmosphere. A fault code stored in the Engine Control Unit (ECU), explains what caused the check engine light to come on.

If the ECU has detected a fault code and triggered the Check Engine Light (CEL) / Service Engine Light, don't necessarily assume that there is an engine problem. The problem could be an emission related problem and the car may drive fine. Still, don't ignore the CEL light. Always read the fault codes via the OBD2 port which you can perform yourself or have an auto mechanic.

An auto mechanic or dealer technicians use specialized equipment (OBD2 scanners) to read the code from the car’s computer (ECU) via the OBD port. This is a simple procedure that Hyundai owners can perform themselves without any prior experience. 

check engine light on hyundai santa feIf the check engine light is on, you have a couple of options.

  1. The most expensive route would be to take your Hyundai to an auto mechanic and pay over $100 for check engine diagnosis. They will read the codes and tell you what is wrong. 
  2. This procedure is so easy, you can perform yourself right on your driveway. All you need is a code reader which can be purchased at any auto parts store or online. Some auto parts stores may even read the codes free of charge. If you don't have an OBD-II code reader consider getting one as they are very useful and can save you hundreds of dollars on car diagnosis. Read this article for tips on Choosing an OBD-II diagnostic scanner for DIYers.
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2. How to read Hyundai check engine codes

Diagnosing Hyundai check engine codes is easy. Any Hyundai owner can read Hyundai codes, right in their driveway. No need to drive to the dealership or pay $100+ for such a simple procedure. 

What you will need

Instructions

Step 1

hyundai sonata check engine light on

Locate the OBD-II port. This is a 16-pin port located under the dashboard on the driver's side. 

Step 2

hyundai codes for check engine light onPlug the scanner into the OBD-II 16-pin port. 

Step 3

turn hyundai igntion on to diagnose check engien light on

Turn the key to on. All the dash lights should turn on. Don't start the engine. 

Step 4

hyundai check engine light on clear codes

Scanner turns on. Hit SCAN or READ button on your OBD-II scanner. You will see fault codes such as P0300. Write down the code and do research online on what those codes mean on Hyundai cars. 

Step 5

Fix the problem that caused the check engine light. You can use the scanner to clear the code or drive the car for a couple of days and the light will turn off after four or five driving cycles.

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3. Common Fault Codes

EVAP Codes

Typically when Hyundai check engine is on but car drives fine you most likely have an Evaporative Emission Control System (EVAP) code. EVAP is used to prevent gasoline vapors from escaping into the atmosphere from the fuel tank and fuel system. 

how to clear hyundai check engineIn many cases that the check engine light turns ON in a Hyundai (Elantra, Sonata, Santa Fe, Accent) the car may still drive perfectly fine. This happens when you have a emissions related problem. The problem here may be something as simple as a loose gas cap. Retightening or replacing the gas cap often will fix the check engine light. If the problem is a loose or defective gas cap and you address that problem, the check engine light will turn off on its own usually in a couple of days. You don't need a scanner to reset it. 

Related fault codes:

  • P0440 Evaporative Emission Control System Malfunction.
  • P0444 Evaporative Emission Control System Purge Control Valve Circuit Open

  • P0422 Main Catalyst Efficiency Below Threshold (Bank 1)

  • P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Hyundai check engine light flashing/blinking

If your Hyundai check engine light is flashing and the car is shaking, that means that you have a serious engine malfunction and you should avoid driving your car. Check engine light flashing and blinking is a result of engine misfire. Replacing the spark plugs and spark plug wires is all that you need to do to fix this problem. In some cases, the check engine light may flash due to a bad ignition coil as well. All these are easy and inexpensive repairs and can be performed by any DIYer. Don't continue to drive a Hyundai that has triggered the check engine light and is shaking; you may cause serious damage to the engine. Not only that but if you are driving in heavy traffic, your engine will overheat. 

Related fault codes:

  • P0300 Random/Multiple Cylinder Misfire Detected

  • P0301 Cylinder 1 Misfire Detected

  • P0302 Cylinder 2 Misfire Detected

  • P0303 Cylinder 3 Misfire Detected

  • P0304 Cylinder 4 Misfire Detected

Check Engine Light on / No Acceleration

what does check engine light mean on hyundai sonataIf your Hyundai will not accelerate and the check engine light is on, it is very likely that a faulty throttle position sensor. Under these conditions, the car will barely move or not accelerate at all. Replacing the throttle position sensor is easy and can be completed by any DIYer in less than one hour.  

Fault codes related to Hyundai CEL on, the car won't accelerate. 

  • P2135 Throttle/pedal position sensor/switch A/B voltage correlation

  • P2135 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch  A/B

  • P2106 FORD Throttle Actuator Control System - Forced Limited Power

  • P2127 Throttle/Pedal Position Sensor/Switch 'E' Circuit Low

  • P2138 Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage

  • P2101 P0222 P0123

Hyundai Check engine light and ESC on

If you both the check engine light and the ESC light come on this means that the accelerator pedal position switch has failed. In such cases, the car will lose all power. Pressing the gas pedal to the floor will not change engine RPMs. The car won't accelerate but you can get your car up to 20 MPH. Try restarting the car as this may fix this problem temporarily. Hyundai sells a redesigned accelerator pedal position switch that should fix this problem. Replacing the sensor at the dealer or a repair shop costs between $200-$450 USD. Installing a used Hyundai Accelerator Pedal is another possible solution. 

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Check Engine Light Flashing

If your check engine light is flashing it means that the engine control unit has detected a misfire. You should stop as soon as possible and have your vehicle towed if necessary to prevent further damage to the engine or catalytic converter. 

What this means is that one or more of your cylinders are not working properly. This can be caused by a number of things such as bad spark plug, faulty ignition coil, bad ECU, clogged catalytic converter. 

If your car is flashing the check engine light and you continue to drive, you can damage the engine or the catalytic which can cost anywhere from $800 to $1500 to replace.

Top 10 Causes of Check Engine Light

Here is a list of the most common causes of Check Engine Light. Average costs to repair these problem has been included. Please note that for high-end vehicles the repair cost can be outside of this range. The repair costs shown below are typical prices you will pay at the dealers and auto repair shop. When a DIYer performs these repairs the average cost is significantly lower. 

  1. Oxygen Sensors 
    • Repair Cost: $200-$400
    • Repair Difficulty: Easy 
  2. Catalytic converter
    • Repair Cost: $750-$1500
    • Repair Difficulty: Moderate 
  3. Spark Plugs
    • Repair Cost: $250-$600
    • Repair Difficulty: Easy
  4. Loose Gas Cap
    • Repair Cost: Free - $25
    • Repair Difficulty: Very Easy
  5. Mass Air Flow MAF Sensor
    • Repair Cost: $200-$400
    • Repair Difficulty: Easy
  6. EVAP Purge Control Valve
    • Repair Cost: $120-$400
    • Repair Difficulty: Easy
  7. Ignition Coils
    • Repair Cost: $140-$600
    • Repair Difficulty: Easy
  8. Thermostat
    • Repair Cost: $200-$650
    • Repair Difficulty: Moderate
  9. Camshaft Position Sensor
    • Repair Cost: $150-$400
    • Repair Difficulty: Easy
  10. Fuel Injectors
    • Repair Cost: $350-$650
    • Repair Difficulty: Easy

Important Notes

  1. Clearing the check engine light using a scanner or by disconnecting the car battery does not fix the problem itself. Clearing codes without fixing the problem simply erases the codes from Engine Control Unit memory. Also keep in mind that if your car requires an emissions test soon after you clear the code, you will fail the emissions test. Clearing (CEL) codes also set the emissions readiness indicators to NOT READY. The car will require a few days of driving or a specific drive cycle to test all the emission systems and set them to READY.
  2. We recommend that you get a second opinion from a professional before you replace any parts. Do not replace car parts based on the fault code alone. It is important to consider the symptoms and the code before you come to a conclusion. For example, you may get a code for a bad oxygen sensor. While the oxygen sensor can surely be defective, a code for oxygen sensor can also be triggered by a cut wire, bad connector,  bad catalytic converter etc. Keep in mind that even a mechanic may have a difficult time diagnosing those rare cases. 
  3. If your check engine light turns on while driving continually monitor the engine temperature and oil pressure light. If any of these lights turn on, safely pull over and turn off the engine. 
  4. Do not ignore the Check Engine Light warning. Diagnose your vehicle as soon as possible.
  5. Auto parts stores such as Advance Auto Parts or AutoZone may offer free scanning of the Check Engine Light. 
  6. Check Engine Light (CEL) may also be referred to as Service Engine Soon (SES), malfunction indicator lamp (MIL). 

Frequently Asked Questions

Yes, disconnecting the battery usually clear the ECU codes. By turning the check engine light off this way you will not fix the problem. If you believe the check engine light needs to be off, drive the car for a few days and the CEL will reset itself. The Onboard Diagnostic System in your car continually monitors your vehicle and will turn off the CEL if the problem is solved. If the problem hasn't been resolved, even if you disconnect the battery, the CEL will come back up again which can be as soon as you restart the car or up to a few days.

If check engine light is on, it will not pass emission inspection/smog test. If the light was recently reset with an OBD2 scanner or by disconnecting the battery, you need to drive the car for a couple of days for the systems to be ready for testing.

It could be because you are using an OBD2 scanner that does not support the protocol used in your car. Try a different scanner. Also, there may be an issue communicating with the ECU due to a damaged wire or ECU malfunction.

No. The check engine light is not the reason why the car doesn't start. If the car doesn't start, read the codes and maybe the CEL will give you a code that can help you diagnose the car. Clearing codes will not make your car start.

It may be just bad timing. An oil change is not going to trigger the CEL. Unless MAYBE a sensor got accidentally unplugged, disconnected or damaged during the oil change. Take your car back to the auto repair shop that changed your oil and have them diagnose the problem.

No, the CEL should not turn on after routine maintenance. If you modified your engine, transmission, exhaust, intake, fuel system or other systems it can affect engine and emission control system, causing check engine or service engine soon light to come on. CEL should not come on if you changed tires or tire size.

Drive the car for a couple of days and allow the ECU to reset itself. If the CEL still remains on, read codes.

The check engine light is trying to tell you that there is a problem with your engine. It could be low coolant, stuck thermostat, transmission not shifting. Figure out why your car is overheating first and address that problem. DO NOT CONTINUE TO DRIVE IF YOUR CAR OVERHEATS.

Comments

Posted by Visitor on Apr 15, 2018 @ 15:09 pm

Posted by Hyundai santa fe on Apr 17, 2018 @ 08:39 am

Posted by Visitor on Apr 18, 2018 @ 13:38 pm