Antilock Brake System (ABS): 1020

1020-CAN BUS COMMUNICATION - GENERAL MALFUNCTION





When Monitored and Set Condition
^ When Monitored: With the ignition on.
^ Set Condition: CAN Bus communication failure between the Controller Antilock Brake (CAB) and the CAN Bus network.

POSSIBLE CAUSES
- CAN C BUS CIRCUIT OPEN
- CAN C BUS CIRCUIT OPEN
- CONTROLLER ANTILOCK BRAKE (CAB)

For a complete Antilock Brake System (ABS) Circuit Diagram, (Refer to - BRAKES/ELECTRICAL - SCHEMATICS AND DIAGRAMS).

Diagnostic Test
1. MEASURE THE RESISTANCE OF THE CAN C BUS (+) CIRCUIT





Turn the ignition off. Disconnect the CAB harness connector.
Disconnect the harness connectors of the other modules on the CAN Bus network.

Note: Check connectors - Clean/repair as necessary.

Measure the resistance of the CAN C Bus (+) circuit from the CAB harness connector to the harness connectors of the other modules on the CAN Bus network.
Is the resistance below 1.0 ohm?
Yes >> Go to 2
No >> Repair the CAN C Bus (+) circuit for an open. Perform ABS VERIFICATION TEST. ABS Verification Test

2. MEASURE THE RESISTANCE OF THE CAN C (-) BUS CIRCUIT





With the ignition off.
Measure the resistance of the CAN C Bus (-) circuit from the CAB harness connector to the harness connectors of the other modules on the CAN Bus network.
Is the resistance below 1.0 ohm?
Yes >> Replace the Controller Antilock Brake (CAB) Module. Perform ABS VERIFICATION TEST. ABS Verification Test
No >> Repair the CAN C Bus (-) circuit for an open. Perform ABS VERIFICATION TEST. ABS Verification Test