Occupant Restraint Controller (ORC)

U0020-CAN B BUS OFF PERFORMANCE







- When Monitored:
Continuously

- Set Condition:
Whenever the CAN B Bus (+) or CAN B Bus (-) circuit is open, shorted to voltage or shorted to ground.





1. VERIFY DTC U0020-CAN B BUS IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, read Occupant Classification Module (OCM) DTCs.

Does the scan tool display active: U0019-CAN B BUS?

Yes

- Go To 2

No

- If the DTC is stored, check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded or contaminated terminals.
- Perform the OCS VERIFICATION TEST. OCS Verification Test.

2. CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE TOTALLY INTEGRATED POWER MODULE (TIPM)
1. With the scan tool, read the Totally Integrated Power (TIPM) DTCs

Does the scan tool display any active CAN B BUS related DTCs?

Yes

- Diagnose and repair the DTC(s).Testing and Inspection.

No

- Go To 3

3. CHECK (D55) CAN B BUS (+) CIRCUIT FOR AN OPEN




1. Turn the ignition off.
2. Disconnect the negative battery cable.

WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
Disconnect the OCM connectors.
3. Disconnect the TIPM C3 harness connector.
4. Measure the resistance of the (D55) CAN B Bus (+) circuit between the TIPM C3 harness connector and the OCM C1 harness connector.

Is the resistance below 2.0 Ohms?

Yes

- Go To 4

No

- Repair the (D55) CAN B Bus (+) circuit for an open.
- Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test.

4. CHECK (D54) CAN B BUS (-) CIRCUIT FOR AN OPEN




1. Measure the resistance of the (D54) CAN B Bus (-) circuit between the TIPM C3 harness connector and the OCM C1 harness connector.

Is the resistance below 2.0 Ohms?

Yes

- Replace the OCM.
- Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test.

No

- Repair the (D54) CAN B Bus (-) circuit for an open.
- Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test.