Engine Control Module: Description and Operation

TOOLS REQUIRED
J 35616-A Connector Test Adapter Kit

The control module system has a computer, the powertrain control module (PCM) that controls fuel delivery, timing, and some emission control systems. The control module system monitors a number of engine and vehicle functions and controls the following operations:
^ Fuel control.
^ Fuel injection timing.
^ Transmission shift and shift quality functions.
^ Specific transmission control diagnostics are covered in the appropriate service manual.

The diesel powertrain control module (PCM) is located in the passenger compartment. The PCM is the control center of the control module system.

The PCM constantly monitors information from various sensors and controls the systems that affect vehicle performance. The PCM performs the diagnostic functions of the system. The PCM can recognize operational problems, alert the driver through the MIL (Service Engine Soon), and store one or more DTCs identifying the problem areas to aid the technician in making repairs.

The PCM is designed to process the various input information and send the electrical responses necessary to control fuel delivery, timing, and other emission control systems. The input information has an interrelation to more than one output, therefore, if input from one source failed, more than one system's operations could be affected.