PCM Learning Ability

The Powertrain Control Module/Engine Control (PCM/EC) has a "learning" ability which allows it to make corrections for minor variations in the fuel system to improve drive ability. If the battery is disconnected, the learning process resets and begins again. A change may be noted in the vehicle's performance. To "teach" the vehicle, make sure that the engine is at operating temperature. The vehicle should be driven at part throttle, with moderate acceleration and idle conditions until normal performance returns. To relearn idle the engine should be idled in D (Drive) with the vehicle at operating temperature until idle stabilizes.

The Transmission Control (TC) portion of the PCM also has a learning ability to achieve smooth shifts. If the battery is disconnected, the Transmission Control Module (TCM) will lose the fine tuning of shift points, which has been learned while driving the vehicle. Disconnecting the battery will not reset the TCM adaptive parameters. The adaptives can only be reset using the Saturn service stall system (SSS) or Scan tool. Tools and Equipment

To relearn the shifts, the vehicle should be driven so that each shift is achieved at least twice.