Control Unit

NOTE: Powertrain Control Module (PCM) may also be referred to as Electronic Control Module (ECM) or Vehicle Control Module (VCM). This is the same component.

PCM is located below center console.

PCM analyzes all electrical data signals from input devices to control fuel injection, ignition and emissions. PCM includes a back-up fail-safe control system. If a malfunction develops in PCM microcomputer, back-up control system will maintain necessary engine functions to permit operation of vehicle.

PROM is factory-programmed engine calibration data, which modifies PCM for specific transmission, engine, emission, vehicle weight and rear axle ratio application. EEPROM (Electronically Erasable Programmable Read Only Memory) provides fuel delivery back-up so engine runs in case of PROM or PCM failure. Anytime PCM is replaced, install original PROM and/or EEPROM into replacement PCM. If battery voltage is removed, PROM and EEPROM information is retained.