Engine Control Module: Description and Operation

PURPOSE
The Powertrain Control Module (PCM) for the EEC-V system is used to adjust air fuel mixture, spark advance, and exhaust gas recirculation.

DESCRIPTION
PCM is the microprocessor of the electronic engine control system and incorporates the ignition control module.

OPERATION
The PCM receives, processes and transmits data to and from relays, sensors, actuators, switches, and other electronic components. From the information gained, the PCM controls fuel economy, driveablity, and optimizes emissions. The PCM performs self-diagnosis and detects failures within the electronic engine control system.

FEATURES
With the preprogrammed performance data and the information from vehicle sensors, the PCM develops an adaptive strategy for operating the ignition, fuel, and EGR systems. The PCM will also adjust the electronically controlled automatic transmission if equipped.

This adaptive strategy is maintained in the PCM memory by a small amount of current from the vehicle's battery when the ignition is OFF.

NOTE: When battery voltage is removed from the PCM, all learned values will be cleared and reset to predetermined values. When battery voltage is restored to the PCM, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle to allow the PCM to relearn values for optimum driveability and performance.

LOCATION
The PCM is mounted forward of the center console between the console front finish panels.