Test M: The Four Wheel Drive (4WD) Control Module Does Not Respond To The Scan Tool

PINPOINT TEST M: THE FOUR WHEEL DRIVE (4WD) CONTROL MODULE DOES NOT RESPOND TO THE SCAN TOOL

M1-M2:

M3-M4:

Normal Operation
The 4WD control module communicates with the scan tool through the high speed controller area network (HS-CAN). Circuits 1908 (WH) (HS-CAN +) and 1909 (BK) (HS-CAN -) provide the network connection to the 4WD control module. The 4WD control module shares the HS-CAN network with the powertrain control module (PCM), the transmission control module (TCM), the power steering control (PSC) module, the traction battery control module (TBCM), the anti-lock brake system (ABS) module, and the instrument cluster. Voltage for the 4WD control module is provided by circuits 704 (DG/LG) and 1003 (GY/YE). Ground is provided by circuit 57 (BK).

Possible Causes
- Fuse
- Circuit 57 (BK) open
- Circuit 704 (DG/LG) open
- Circuit 1003 (GY/YE) open
- Circuit 1908 (WH) open (HS-CAN +)
- Circuit 1909 (BK) open (HS-CAN -)
- 4WD control module