P040C - OBD Trouble Code

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The error code P040C can be identified as Exhaust Gas Recirculation Temperature Sensor 'A' Circuit Low.

The engine trouble codes refer to the flaws in the exhaust gas recirculation system. An integral part of the vehicles emission system is the EGR whose main motive is to prevent the harmful nitrogen oxides from forming in the cylinders. It is the engine management computer which operates the EGR.

This trouble code is generic, which would mean that it can apply to all the vehicles which are equipped with the OBD-II or the vehicles which are made since 1996 up to the present. The specifications on the definition, the troubleshooting steps as well as repairs can always vary from one vehicle make to another.

This can happen because of a lot of reasons and the mechanic should diagnose the specific cause for this code.

What causes this problem with the Exhaust Gas Recirculation Temperature Sensor “A” Circuit Low?

• Exhaust gas recirculation temperature Sensor 'A' harness might be opened or shorted
• There can be bad electrical connection in the exhaust gas recirculation temperature Sensor 'A' circuit
• Defective exhaust gas recirculation temperature sensor
• Some quirks in the connector
• Engine control module might be faulty
• Issue of poor connections
• EGR temperature sensor gasket might be leaking
• Issue of cracked or leaking exhaust pipe in which the sensor is mounted
• The wiring harness or sensor might be burnt
• Defects in the wires
• Quirks in the exhaust gas recirculation temperature sensor 'A'

1. Ambient Air Temperature Sensor - Do you remember when was the last time you got your car Ambient Air Temperature Sensor checked up? A defected Ambient Air Temperature Sensor can cause a lot of issues like displaying P040C code.
2. Powertrain Control Module - Poor Powertrain Control Module can cause a lot of difficulties, so why not get it replaced at time?
3. Coolant Temperature Sensor - Are there some faults in your Coolant Temperature Sensor? Don’t waste time and get them replaced or else P040C code can turn up.
4. Engine Control Module - OBD Code P040C can appear because of faulty Engine Control Module.
5. Throttle Position Sensor - Everything is fine with Coolant Temperature Sensor and still P040C code triggering? Then you must get your Throttle Position Sensor checked.
6. EGR Valve Gasket - There can be some issues with the EGR Valve Gasket due to which you may see P040C code appearing over and over again. Visit us to buy best quality EGR Valve Gasket online.
7. Fuel Temperature Sensor - A lot of issues can arise do to defective Fuel Temperature Sensor. Did you just see P040C code flashing? Now you know the reason why it is appearing. Get it inspected and replaced on time.

Our main motive is to achieve customer satisfaction and that’s why we will help you to diagnose P040C code by mentioning some major symptoms below:

Common Symptoms

• There can be a failure in the smog or emissions state
• A lot of exhaust smells
• Appearance of service engine soon warning light
• Engine noise might start coming
• Louder exhaust

If you wish to correct this fault code, then you have to follow certain steps. Correcting a problem needs your careful attention. Here are some ways with the help of which you will be able to correct the OBD Code P040C:

• Make sure to repair the connections
• If there are some flaws in the connector, then you can always repair it
• Replace the defective engine control module
• You can always repair the flawed wires
• Leakage in the EGR temperature sensor gasket should be corrected properly
• Replace or repair the exhaust gas recirculation temperature sensor

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Here are some steps which you should follow in order to diagnose this fault code:

• The first and the foremost step would be to check by visually inspecting the sensor and surrounding EGR system, looking for exhaust leaks in particular. Also check out the sensor and its harness. Remember that high temps can cause havoc on plastic and rubber insulated wires so inspect them thoroughly
• Keep in mind that the black soot may indicate an exhaust leak around the area. A lot of EGR issues have been caused due to accumulated soot in the exhaust potentially caused by a number of things (poor maintenance, low quality fuel etc.). In this case, it is not an exception, so it can be a good idea to clean your EGR system or at the very least the temperature sensor.
• Be aware that sensors mounted within the exhaust systems may feel like they are seized when trying to unfasten. Just remember that these sensors are subject to substantial temperature fluctuations, so a bit of heat using an Oxyacetylene torch (not for the layman) may help loosen the sensor
• Now once you have removed the sensor use carburetor cleaner or similar product to effectively soak the soot. Use a wire brush to loosen soot in any overly accumulated areas.
• When you are reinstalling the clean sensor, make sure to apply some anti-seize to the threads to aid in preventing seizing. Verify the integrity of the sensor by measuring actual electrical values compared to manufacturer specific desired values. This can be done by using a Multimeter and following manufacturer specific pin-out test procedures

P040A - Exhaust Gas Recirculation Temperature Sensor "A" Circuit

P040B - Exhaust Gas Recirculation Temperature Sensor "A" Circuit Range/Performance

P040D - Exhaust Gas Recirculation Temperature Sensor "A" Circuit High