Test B

Pinpoint Test B: No Communication With The Four-Wheel Drive (4WD) Control Module - Electronic Shift

Normal Operation


The 4WD control module communicates with the diagnostic tool through the universal asynchronous receiver-transmitter (UA~-based protocol (U BP) communications network circuit 693 (OG). If the 4WD control module loses power it will not be able to communicate. Check power circuit 972 (BKIWH) and ground circuit 1203 (BK/LB) for open. If circuits prove out, refer to Information Bus for further diagnostics.


Possible Causes

- circuit 972 (BK/WH)

- circuit 1203 (BK/LB)

- 4WD control module circuit 693 (OG)

PINPOINT TEST B: NO COMMUNICATION WITH THE FOUR-WHEEL DRIVE (4WD) CONTROL MODULE