Computers and Control Systems: Description and Operation

Computer Module:

ECM Inputs And Outputs:

PURPOSE:
At the heart of the Computer Command Control System (C3) is the Electronic Control Module (ECM). The ECM, with the help of input sensors, monitors a number of engine and vehicle operating functions to maintain compliance with exhaust emission levels while providing good driveablity and fuel efficiency.

OPERATION:
ECM Controlled Systems:
^ Fuel Delivery
^ Ignition/Electronic Spark Timing (EST)
^ Electronic Spark Control (ESC)
^ Air Conditioning Compressor Clutch
^ Coolant Fan
^ Engine Idle Speed
^ Evaporative Emission Control
^ Torque Converter Clutch (TCC)

SELF DIAGNOSTICS AND "SERVICE ENGINE SOON" LIGHT:
The C3 system has a built-in diagnostic system that recognizes and identifies possible operational problems. The C3 system 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 same light is combined with the built-in diagnostic system in order to assist the technician in locating and correcting problems within the C3 system. It does this by flashing a series of codes which identify the possible problem areas at fault, within the C3 system. The system also allows for near normal driving conditions during system malfunction, through the use of the built-in backup system. The backup system remains in effect until repairs can be made.