Pinpoint Test 1: No Communication With Four-Wheel Drive (4WD) Control Module
PINPOINT TEST 1: NO COMMUNICATION WITH FOUR-WHEEL DRIVE (4WD) CONTROL MODULENormal Operation
The active, on-demand 4WD system utilizes 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, transaxle range from the PCM, as well as 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 controller area network (CAN). If other modules communicate with the WDS or equivalent Tester and the 4WD control module does not, check the power and ground circuits to the 4WD control module before replacement of the module.
Possible Causes
^ circuit (DG/LG)
^ circuit (GY/Y)
^ circuit (B)
^ 4WD control module
Note: Conduct steps 1-7 outlined in Inspection and Verification prior to performing this test.