Engine Control Module: Description and Operation

OPERATION:
The control module is located in the passenger compartment and is the control center of the Computer Command Control system. The control module constantly receives information from various sensors. The computer performs the diagnostic functions of the system. The computer can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) (Service Engine Soon light). The computer stores a trouble code which identifies the problem area to diagnose and repair. The computer is designed to process the various input information, and send the necessary electrical response to control fuel delivery, spark control, and other emission control systems. The input information has an interrelation between sensor output. If one of the input devices failed, such as the oxygen sensor, this could affect more than one of the systems controlled by the computer.

The computer has a learning ability which allows it to make corrections for minor variations in the fuel system to improve driveability. If the battery is disconnected to clear trouble codes or for repair, the learning process has to begin all over again, and a change may be noticed in the driving performance of the vehicle. To reset the vehicles learning ability, make sure the engine is at operating temperature and operate the vehicle at part throttle, moderate acceleration, and idle conditions, until normal performance returns.