Computers and Control Systems: Description and Operation

PCM Access Cover:

Purpose:
The Computer Command Control System uses a Powertrain Control Module (PCM) capable of monitoring a number of engine and vehicle operating functions. The PCM controls the following systems:

^ Fuel Metering System
^ Transaxle Shifting
^ Cruise Control Operation
^ Ignition Timing


Operation:
The computer system has a built-in diagnostic system that recognizes and identifies possible operational problems.

The PCM signals the driver through a "SERVICE ENGINE SOON" light located on the instrument panel. The "SERVICE ENGINE SOON" light will remain "ON" until the problem is identified and repaired. This light is combined with the built-in diagnostic system in order to assist the technician in locating and correcting problems within the system. The light, by flashing a series of codes, identify the possible problem areas at fault.

The system also allows for near normal driving conditions during system malfunction, through the use of a built-in backup system. The backup system remains in effect until repairs can be made.