After replacing engine management components, many vehicles will require a reset of the parameters to tell the ECU that a new part has been fitted. Without this, the ECU will believe that the engine is still running with faulty sensors and will default back to data already received before the replacement. This causes the vehicle to run poorly, normally with the Malfunction Indicator Lamp on and the fault code still logged in memory.
Reset parameters as follows
- Firstly, reset the vehicle using diagnostic tools.
- If the fault code persists, perform a manual reset according to the manufacturers instructions, commonly as follows:
- Carry out 3 drive cycles:
A. Turn ignition on, turn ignition off
B. Turn ignition on, turn ignition off
C. Start the engine.
- An extended road test, normally around 20 miles is then required to provide the ECU with enough data to allow the sensor to function correctly.