GM Service Manual Online
For 1990-2009 cars only

Object Number: 187237  Size: SH

The Powertrain Control Module (PCM) is the control center of the vehicle. It controls the following items:

    • Fuel metering system.
    • Transaxle/transmission shifting.
    • Ignition timing.
    • On-board diagnostics for powertrain functions.

It constantly monitors the information from various sensors, and controls the systems that affect vehicle performance. The PCM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the MIL, and store diagnostic trouble codes which identify the problem areas to aid the technician in making repairs.

The type of PCM used is a PCM 32U. The knock sensor system is no longer a separate component. The PCM contains integrated knock sensor (KS) diagnostic circuitry. For further information, refer to Knock Sensor (KS) System Description