Normal Operation

The on-demand 4WD system uses data from other systems as inputs to the 4WD control module. The 4WD control module uses the inputs to determine the appropriate duty cycle to send to the active torque coupling that delivers the desired torque to the rear wheels. Specific inputs to the 4WD control module are: throttle position output from the PCM, transmission range from the PCM, brake system status and all 4 wheel speeds from the ABS module. Communication between the 4WD control module and other modules is obtained through the high speed CAN. If the 4WD control module loses communication with, or receives invalid data from any of the necessary modules, DTCs are set and the 4WD control module may not allow 4WD operation.