Test D: 4WD Control Module No Response To Diagnostic Tool

PINPOINT TEST D: THE FOUR-WHEEL DRIVE (4WD) CONTROL MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

D1-D3:

Normal Operation
The 4WD control module communicates with the diagnostic tool through the international standards organization (ISO) 9141 communication network circuit 70 (LB/WH). If circuit 70 (LB/WH) becomes open or shorted to ground communications to that module are not possible. Check circuit 70 (LB/WH) between the 4WD control module C281a and the data link connector (DLC) C251. The total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open in circuit 70 (LB/WH), damage to the DLC C251, or damage to the 4WD control module C281a.

Possible Causes
- ISO 9141 communication network circuit 70 (LB/WH) open
- 4WD control module C281a
- 4WD control module