Powertrain Control Module (PCM) Description: Notes

Fig 1: View Of PCM Cover

Courtesy of GENERAL MOTORS CORP.

The powertrain control module (PCM) is a precision unit consisting of a one chip microprocessor, an analog/digital (A/D) converter, and an input/output (I/O) unit. The PCM is an essential part of the electronic control system. The PCM is responsible for such major functions as control of the fuel injectors, the idle air control (IAC) valve, the fuel pump relay, etc. The PCM performs the OBD 2 diagnostic tests of the emission related systems. The PCM supplies a buffered voltage to the various information sensors and switches. The PCM controls most components with an electronic switch that completes a ground circuit when turned on. The PCM is also responsible for a self-diagnosis function and a fail-safe function.

The PCM (1) is located below the glove box, underneath the instrument panel, on the right side of the passenger compartment.