Control Module Communications

The control module system has a computer, the engine control module (ECM), 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 through the fuel injection control module (FICM):
^ Fuel rail pressure.
^ Fuel injector.
^ Fuel injector pulse width.

The diesel Engine Control Module (ECM), located in the engine compartment, is the control center of the control module system. The engine control module used on the electronic fuel injected 6.6 L diesel is referred to as a ECM.

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

The ECM 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 that input could effect more than one systems operation.