Acura Check Engine Light Troubleshooting
Updated Thursday Sep 28, 2017
If your Acura check engine light is on, don't panic. In this article, we will show you how easy it is to diagnose Acura check engine light yourself using an OBD2 Scanner. You will also learn about some of the most common causes that trigger the check engine light on Acuras are and how they are fixed.
If Acura check engine light is on, the problem could be due to engine issues, emission system or in some cases even automatic transmission related. Before you take your Acura in for service, learn how to read and reset check engine light on Acura yourself, common CEL causes and symptoms of check engine light on an Acura.
1. Acura Check Engine Light Symptoms
If the check engine light on an Acura comes on, you may NOT notice any performance issues.
Or you may notice problems such as:
- Engine Missifre,
- Poor Acceleration,
- Variable Torque Managemen VTM-4 Light On
- Acura Check engine light on and off
- Acura check engine light and TCS
- Acura check engine light blinking
If you have the check engine light on but do not notice any problems or issues note that there may be a performance decrease. For example, you may have poor fuel economy or increased emissions. It is not recommended to operate the Acura with the check engine light on for extended periods of time. If you think the problem is a loose gas cap tighten the fuel cap. The check engine light on your Acura is not going to turn off right away. It will require a couple of days of normal driving for the light to reset on an Acura.
2. How to read Acura check engine light codes
The following procedure will allow you to read codes and reset check engine light on Acura cars. These instructions work on all 1996 and newer Acura vehicles including Acura TL, MDX, RDX, RLX, TSX, Integra, CL, ILX, TLX, RLX, ZDX, RL. You will need an OBD2 scanner to read the trouble codes.
Step 1: Locate OBD2 Port Under the dashboard
Step 2: Plug your OBD2 scanner.
Step 3: Turn ignition on
Step 4: Scanner will power up
Step 5: Press enter on the scanner
Step 6: Read codes
Step 7 Clear codes. Codes will come back until you fix the underlying problem.
Don't start replacing Acura parts based on the fault code alone. Do some research on the specific code and pay close attention to the symptoms. For example, you may get a code that points to a bad oxygen sensor. After you replace the oxygen sensor you still get the same fault code. You give up and take the Acura to a mechanic. They call and inform you that that the problem wasn't the oxygen sensor but a clogged catalytic cover. Always pay attention to the symptoms and do some research before you start replacing parts on your Acura.Back to top
3. Acura Check Engine Light Causes
Oxygen sensors (O2) may fail on Acuras. When this happens there is no way to measure the amount of oxygen in your Acura's exhaust system. The engine will end burning more fuel than needed. Not only will you notice poor fuel mileage but if this problem is ignored for a long period of time it can cause damage to the catalytic converter.
Acura Oxygen Sensor Symptoms
- Poor fuel economy
- Acura may idle too high
- High fuel consumption
Acura Oxygen CEL Codes
- P0135 ACURA O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1
- P0133 ACURA O2 Sensor Circuit Slow Response Bank 1 Sensor 1
- P0141 ACURA O2 Sensor 1 Sensor 2 Heater Circuit Malfunction Bank
- P0158 ACURA O2 Sensor Circuit High Voltage Bank 2 Sensor 2
- P0174 ACURA Fuel System Too Lean Bank 2
Gas Cap Loose
A loose Acura gas cap can cause the check engine light to come on. We all have forgotten or will forget to put on the gas cap or tighten it until you hear it click. The gas cap seals the fuel tank. The fuel tank needs to maintain a constant pressure which is lower than the atmospheric pressure. That's why if you forget to tighten the gas cap the check engine light may turn on. It is possible that the gas cap gasket also fails and it no longer provides a proper seal. If you left the gas cap off or loose the check engine light will turn on. Just tighten the gas cap. As the Acura goes through driving cycles, it will reset the check engine light on its own within a couple of days.
Loose Gas Cap Codes
- P0455 Acura EVAP System Large Leak Detected
- P1456 AcuraEvaporative Emissions Control System Leakage
- P1457 Acura Evaporative Emissions Control System Leakage
- P0442 Acura EVAP System Very Small Leak Detected
The catalytic converter may fail on Acuras causing the check engine light to come on. If the catalytic converter fails or gets clogged your Acura's fuel efficiency will decrease. If you step on the gas pedal you may feel that your Acura is struggling to accelerate. If your cats are completely clogged your Acura will not even start. You won't be able to pass an emissions test with a failed catalytic converter. Replacing the catalytic converter at Acura dealerships will cost you anywhere from $900-$1600. A cheaper alternative is to install an aftermarket catalytic converter at a fraction of the dealer cost.
- Acura may not start
- Poor acceleration
- Acura struggles to go uphill
- Failed emission test
- Significant fuel efficiency decrease
Acura Catalytic Converter Codes
- P0420 ACURA Catalyst System Efficiency Below Threshold Bank 1
- P0430 ACURA Catalyst System Efficiency Below Threshold Bank 2
- P2096 Post Catalyst Fuel Trim System Too Lean Bank 1
Mass Air Flow Sensor (MAF)
The mass air flow sensor on an Acura measures the amount and temperature of air entering the engine. This allows the engine to determine how much fuel to send to the engine so that the proper air to fuel ratio is maintained. When the MAF sensor fails Acura check engine light will come on. If ignored for a long period of time a bad MAF will cause damage to the spark plugs, oxygen sensors and ultimately the catalytic converter. Replacing the MAF sensor in an Acura is an easy DIY.
Symptoms of a bad MAF sensor on an Acura include:
- hard to start,
- engine stalls,
- Acura starts then dies,
- Acura hesitates under acceleration,
- engine hiccups,
- higher RPMs at idle.
Mass Air Flow Sensor Codes
- P1103 ACURA Mass Airflow Sensor Higher Than Expected
- P0101 ACURA Mass Air Flow Circuit Range/Performance
- P0068 ACURA Manifold Absolute Pressure/Mass Air Flow Sensor
- P0102 Mass or Volume Air Flow Circuit Low Input
- P0103 Mass or Volume Air Flow Circuit High Input
- P0104 Mass or Volume Air Flow Circuit Intermittent
Sparks plugs are the most critical part of an Acura engine. They ignite the fuel in the combustion chamber. If your Acura has high mileage and the spark plugs have never been changed, you will notice performance issues and even the check engine light may come on.
Symptoms of worn Acura spark plug include:
- high fuel consumption,
- poor throttle response,
- engine idles roughly,
- Acura hard to start,
- engine hesitation,
- high fuel consumption
Acura Spark Plug Related DTC Codes
- P0300 ACURA Random Cylinder Misfire Detected
- P0301 ACURA Cylinder Number 1 Misfire Detected
- P0302 ACURA Cylinder 2 Misfire Detected
- P0303 ACURA Cylinder 3 Misfire Detected
- P0304 ACURA Cylinder 4 Misfire Detected
- P0305 ACURA Cylinder 5 Misfire Detected
- P0306 ACURA Cylinder 6 Misfire Detected
Acura ignition coils may fail to cause the check engine light to come on. Acura ignition coils converts 12 volts current to thousands of volts needed to create the spark at the tips of the spark plug. They are installed on top of the spark plug. Ignition coils generate up to 50,000 volts and release this voltage at the spark plugs tip which causes the spark and ultimately fire up the compressed air/fuel mixture. If you read the codes from your Acura and get a code related to a faulty ignition coil, replace it as soon as possible. You don't need to replace all the ignition coils, just replace the one that is faulty at least. If you drive your Acura with check engine light on and a bad ignition coil, you will eventually cause the catalytic converter to fail which is a much more expensive repair. Replacing the ignition coils on an Acura is an easy task. If you have ever changed the oil, you can change an ignition coil on a four cylinder Acura.
If one of the ignition coils fails on your Acura, it will trigger the check engine light. Here are some of the common symptoms you will notice if you have a bad ignition coil on an Acura: Engine shaking, Acura hesitates to start, Poor fuel economy, engine misfiring, Acura stalling, Catalytic converter glowing red due to unburned fuel from the engine, Acura backfires, Acura idles rough
Acura Ignition Coil Fault Codes
- P0300 ACURA Random Cylinder Misfire Detected
- P0351 ACURA Ignition Coil 1 Circuit Malfunction
- P0352 ACURA Ignition Coil 2 Circuit Malfunction
- P0353 ACURA Ignition Coil 3 Circuit Malfunction
- P0354 ACURA Ignition Coil 4 Circuit Malfunction
- P0355 ACURA Ignition Coil 5 Circuit Malfunction
- P0356 ACURA Ignition Coil 6 Circuit Malfunction
- P1394 Ignition Coil Power Output Stage 2 Malfunction
The evaporative emissions purge control valve (EVAP) can cause the check engine light on Acura. The purge valve controls the amount of fuel vapor that is purged from the charcoal canister. It allows for vapors to enter the engine instead of being released into the atmosphere. On high mileage Acuras, the purge valve can stick triggering the check engine light.
Some of the most common symptoms of a sticking purge solenoid include:
- Check engine light on,
- Acura has rough idle
Acura Purge Valve Related Codes
- P0443 ACURA EVAP Canister Purge Valve Circuit Malfunction
- P1457 ACURA Evaporative Emissions Control System Leakage
- P0496 ACURA Evaporative Emission System High Purge Flow
- P0455 ACURA EVAP System Large Leak Detected
If the thermostat fails on your Acura, it can take too long for the engine to warm up. The engine control unit (ECU) in your Acura detects this and will trigger a fault code such as P0128 and turn on the check engine light because the engine is taking too long or isn't able to reach normal operating temperature. When the thermostat on an Acura gets stuck in the open position, it takes a very long time for the engien to warm up. If the thermostat gets stuck in closed position, your Acura engine will overheat because there is no coolant circulating and cooling down the engine.
A few of the symptoms that you may notice when the thermostat is stuck. Acura check engine light on with code P0128, Engine take a long time to warm up, Poor engine performance, Engine overheating if thermostat stuck closed
Thermostat Related Fault Codes
- P0128 ACURA Coolant System Malfunction
- P1486 ACURA Thermostat Range/Performance Problem
- P0118 ACURA Engine Coolant Temperature Sensor 1 Circuit High
Acura Check Engine Light & Transmission Problem
Acura check engine light may turn on due to problems with the automatic transmission. When you read the fault codes with an OBD2 scanner, you will get fault codes that start with P07XX. These are generic transmission codes. To properly diagnose Acura transmission problems you will need to use a multi-system scanner that is capable of reading Acura transmission codes.
- Some symptoms that you may notice when Acura check engine light is caused by transmission problems.
- Acura won't shift gears
- Acura stuck in gear and check engine light on
- Check Engine Light and D4 light flashings
- No response when you press the gas pedal
Acura CEL / Transmission Fault Codes
- P0740 ACURA Transmission Lock-Up Control System Fault
- P0700 ACURA Automatic Transmission Fault
- P0710 ACURA Transmission Fluid Temperature Sensor Circuit Fault
- P0847 ACURA 3rd Clutch Transmission Fluid Pressure Switch
Variable Valve Timing & Lift Electronic Control (VTEC) system activates the rocker arm oil control solenoid and it charges/discharges the hydraulic circuit of the VTEC mechanism. This allows the valve timing to change. Engine control module monitors oil pressure in the hydraulic circuit of the VTEC mechanism and the rocker arm oil pressure switch downstream of the rocker arm oil control solenoid. If there is a difference between the oil pressure in the hydraulic circuit and the oil pressure that is determined by the status of the rocker arm oil pressure switch and a fault code is stored.
- Poor engine performance
- Poor acceleration
- Acura Check Engine Light on
VTEC Related Fault Codes
- P1259 ACURA VTEC System Malfunction
- P1258 ACURA VTEC System Malfunction
- P1253 ACURA VTEC System Malfunction
- P1279 ACURA VTEC System Malfunction Front Bank 2
- P2646 ACURA Rocker Arm Oil Pressure Switch Circuit Low Voltage
- P2649 ACURA Rocker Arm Oil Control Solenoid Circuit High Voltage
Acura check engine light may come on due to vacuum leaks. If your engine isn't idling properly or the RPMs fluctuate between high and low, a vacuum leak can be the problem. Hoses on Acura engines can dry out and crack over time. As this happens, they create small vacuum leaks allowing measured air to enter the motor. Vacum leaks can also be caused by loose hose clamps and connections. Replacement vacuum hoses are cheap but the real challenge is tracking down to find what's causing the vacuum.Back to top
4. Acura Check Engine Light Flashing
If your Acura check engine light is blinking it usually means there is an engine misfire. When this happens your engine will shake at idle. Fuel will exit the engine unburned and end up burning at the catalytic converter due to the high temperature there. Catalytic converters operate at high temperatures but if fuel makes it there, it raises the temperature even higher which is often indicated by the catalytic converter glowing red. If you continue to drive your Acura with the check engine light blinking you will cause for ther damage such as damaging the catalytic convert wich is an expensive repair.Back to top
5. Acura Check Engine Light Flashes 5 Times
When you turn the key to position II but don't start the car after 20 seconds your Acura check engine light may flash five times. This happens when the fault codes were cleared with an OBD2 scanner or if the battery was disconnected. What it means is that the emission systems have are not ready. If the CEL light comes on and turns off, the emission readiness (I/M) is complete and you can go pass the emissions test. If the light is flashing five times, you won't be able to pass a state emission test until the emission readiness is set. You can learn more about this in your Acura owner's manual.
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