Restraints
U0020-CAN B BUS OFF PERFORMANCE
For a complete wiring diagram refer to Diagrams/Electrical.
- When Monitored:
Continuously
- Set Condition:
Whenever the CAN B Bus (+) or CAN B Bus (-) circuit is open, shorted to voltage, or shorted to ground.
Diagnostic Test
1. VERIFY DTC U0020-CAN B BUS OFF PERFORMANCE IS ACTIVE
Turn the ignition on.
With the scan tool, read Occupant Classification Module (OCM) DTCs.
Does the scan tool display active: U0020-CAN B BUS OFF PERFORMANCE?
Yes
- Go To 2
No
- Perform *STORED LOST COMMUNICATION DTCS diagnostic test. Stored Lost Communication DTCs
2. CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE TOTALLY INTEGRATED POWER MODULE (TIPM)
With the scan tool, read TIPM DTCs
Does the scan tool display any active CAN B BUS related DTCs?
Yes
- Diagnose and repair the DTC(s).
No
- Go To 3
3. CHECK (D55) CAN B BUS (+) CIRCUIT FOR AN OPEN
Turn the ignition off.
Disconnect the negative battery cable.
Disconnect the OCM connectors.
Disconnect the TIPM C7 connector.
Measure the resistance of the (D55) CAN B Bus (+) circuit between the TIPM C7 connector and the OCM C1 connector.
Is the resistance below 2.0 ohms?
Yes
- Go To 4
No
- Repair the (D55) CAN B Bus (+) circuit for an open.
- Perform *OCM SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
4. CHECK (D54) CAN B BUS (-) CIRCUIT FOR AN OPEN
Measure the resistance of the (D54) CAN B Bus (-) circuit between the TIPM C7 connector and the OCM C1 connector.
Is the resistance below 2.0 ohms?
Yes
- Go To 5
No
- Repair the (D54) CAN B Bus (-) circuit for an open.
- Perform *OCM SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
5. REPLACE THE OCCUPANT CLASSIFICATION MODULE
WARNING: To avoid serious or fatal injury, turn the ignition off, disconnect the battery and wait two minutes before proceeding.
Repair
- Replace the OCM.
- Perform *OCM SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test