Theory Of Operation
The Final Control Module (FDCM) communicates with other controllers over the CAN C bus. The FDCM continuously monitors the bus activity and receives the messages it needs. The CAN C bus is also used to communicate FDCM MIL status to the Engine Controller, therefor if the Engine Controller is unable to communicate with the FDCM, the Engine Controller will light the MIL.
The ABS communicates with other controllers over the CAN C bus. The FDCM Module continuously monitors the bus activity and receives the messages it needs. If the FDCM does not receive messages from the ABS Module , then this fault will set and the service 4WD is illuminated.
The Totally Integrated Power Module (TIPM) communicates with other controllers over the CAN C bus. The FDCM Module continuously monitors the bus activity and receives the messages it needs. If the FDCM does not receive messages from the TIPM Module , then this fault will set and the service 4WD is illuminated.