Test E: The Four Wheel Drive (4WD) Control Module Does Not Respond to the Scan Tool

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

E1-E3:

E3-E4:

Normal Operation
The 4WD control module communicates with the scan tool through the high speed controller area network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the 4WD control module. The 4WD control module shares the HS-CAN with powertrain control module (PCM), the transmission control module (TCM) (if equipped), the anti-lock brake system (ABS) module, the restraints control module (RCM), the occupant classification sensor module and the instrument cluster. Voltage is supplied by circuits CBP18 (GY/OG), SBB23 (RD/WH) and SBB26 (RD/BK). Ground is supplied by circuits GD138 (BK/WH) and GD145 (BK/BU).

Possible Causes
- Fuse
- Circuit CBP18 (GY/OG) open
- Circuit GD138 (BK/WH) open
- Circuit GD145 (BK/BU) open
- Circuit SBB23 (RD/WH) open
- Circuit SBB26 (RD/BK) open
- Circuit VDB04 (WH/BU) open (HS-CAN +)
- Circuit VDB05 (WH) open (HS-CAN -)
- 4WD control module