Powertrain Control Module (PCM)

The powertrain control module (PCM) controls the SERVICE ENGINE SOON, engine temperature, SHIFT TO D2 (automatic transaxles), and upshift (manual transaxle) indicator lamps. It controls these lamps by pulling the circuit to ground. When the circuit is pulled to ground, the indicator lamp for that circuit is illuminated.

The PCM also supplies the speed signal input to the integrated circuit (IC), located in the instrument cluster, for control of the speedometer and odometer. The PCM receives a vehicle speed input from the vehicle speed sensor.