Powertrain Control Module (PCM)

The control module system has a computer, Powertrain Control Module (PCM) to control 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.
^ Exhaust gas recirculation.
^ Transmission shift and shift quality functions.
^ Specific transmission control diagnostics are covered in Transmissions.

The diesel Powertrain Control Module (PCM), located in the passenger compartment, is the control center of the control module system. The Powertrain Control Module used on the electronic fuel injected 6.5L diesel is referred to as a PCM.

The PCM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The PCM performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the MIL (Service Engine Soon), and store one or more DTCs which identify the problem areas to aid the technician in making repairs. See the specific diagnosis procedure for more information.

The PCM processes the various input information and sends the necessary electrical responses to control fuel delivery, timing and other emission control systems. The input information has an interrelation to more than one output, therefore, if the one input failed it could effect more than one system's operation.