Test A: The Four-Wheel Drive (4WD) Control Module Does Not Respond to the Diagnostic Tool
PINPOINT TEST A: THE FOUR-WHEEL DRIVE (4WD) CONTROL MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOLA1-A3:
Normal Operation
The 4WD control module communicates with the diagnostic tool through the international standards organization (ISO) 9141 communications network, circuit 70 (LB/WH). Check circuit 70 (LB/WH) between the 4WD control module C281b, and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in the ISO 9141 circuit, damage to the DLC C251, damage to the 4WD control module C281b, or a problem in an in-line connector.
Possible Causes
- ISO 9141 communications network, circuit 70 (LB/WH) open
- 4WD control module C281b
- 4WD control module