P2031 code definition
Exhaust Gas Temperature (EGT) Sensor Circuit Bank 1 Sensor 2
What the P2031 code means
P2031 is an OBD-II generic code for when the Engine Control Module (ECM) detects that, during the exhaust gas temperature (EGT) sensor warm up after the engine is cold started, the sensor does not register the specified temperature range during the testing timeframe.
What causes the P2031 code?
The ECM monitors the EGT for an exhaust temperature rise after the engine is started cold. If the temperature is not in a specified temperature range within a certain amount of time, then the ECM flags a fault and turns on the Check Engine Light.
The EGT cannot register the exhaust system temperature due to a faulty sensor or wiring.
The EGT cannot register the correct exhaust temperature due to soot or ash build up on the sensor, or there is an exhaust leak.
What are the symptoms of the P2031 code?
The Check Engine Light will be illuminated and the code for a fault in the EGT sensor circuit will be set in the ECM.
The engine may run too rich or lean, depending on manufacturer's failure strategy.
The failure mode will depend on other symptoms encountered.
The exhaust may be leaking before the sensor.
How does a mechanic diagnose the P2031 code?
Scans and documents the codes in the ECM and looks at the freeze frame data for failures
Checks the EGT sensor and wiring for damage and listens for exhaust leaks near the sensor
Verifies the exhaust temperature of the EGT sensor 1 for bank 1 and compares it to the EGT sensor 2 for bank 1 and replaces the sensor if it is not reading as specified.
Common mistakes when diagnosing the P2031 code
- Not removing the EGT sensor and checking for excessive soot or ash on the sensor
- Failing to clean the EGT sensor and retesting before replacing it
How serious is the P2031 code?
Code P2031 is an indication that the ECM has detected the EGT sensor is not reading correctly and the sensor may be indicating a more major problem in the engine causing the wrong temperature readings during engine warm up.
What repairs can fix the P2031 code?
- Removing and cleaning excessive soot and ash off of the EGT sensor
- Replacing the EGT sensor or repairing the wiring to it
- Repairing an exhaust leak in the pipe connection above the sensor
Additional comments for consideration regarding the P2031 code
Code P2031 is for an exhaust temperature sensor on some diesel engines and indicates the sensor did not reach a specific temperature within about a five minute timeframe. Excessive soot or ash build up can insulate the sensor from indicating an accurate temperature. Cleaning the sensor may fix most problems.
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