The Power Control Module, controlling most of the engine functions, may need to be reset in order to clear stored codes within the system. Resetting the PCM is especially useful after making repairs based off of warning lights on the dashboard, and resetting the PCM will clear the stored trouble codes. On a 2002 Pontiac Grand Am, the PCM can be reset in a few minutes by almost all vehicle owners with no mechanical experience.
Loosen the negative battery cable from the negative battery terminal with a 10mm wrench.
Pull the negative battery cable from the terminal, ensuring the end of the cable is not touching any part of the terminal.
Wait 15 minutes.
Connect the negative battery cable back to the negative battery terminal.
Attach the negative battery cable to the negative battery terminal, using a 10mm wrench.
Turn the vehicle on. Allow it to run in Neutral for 10 minutes in a well-ventilated area to allow the PCM to relearn the correct engine idle.
