CAN B BUS Off Performance ORC

U0020 - CAN B BUS OFF PERFORMANCE ORC

U0020 - Can B Bus Off Performance - ORC:

WHEN MONITORED
Continuously

SET CONDITION
Whenever the CAN B Bus (+) or CAN B Bus (-) circuit is open, shorted to voltage, or shorted to ground.

POSSIBLE CAUSES
- Active U0020 CAN B BUS DTC in occupant classification module
- (D55) CAN B BUS (+) circuit open
- (D54) CAN B BUS (-) circuit open
- Occupant restraint controller (ORC)

Diagnostic Test

1. VERIFY DTC U0020 - CAN B BUS OFF PERFORMANCE - ORC IS ACTIVE

Turn the ignition on.
With the scan tool, read Occupant Restraint Controller (ORC) DTCs.

Q: Does the scan tool display active: U0020 - CAN B BUS OFF PERFORMANCE - ORC?

YES: Go To 2
NO: If the DTC is stored, check for an intermittent condition by inspecting the related wiring harness for chaffed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Perform ORC VERIFICATION TEST - VER 1. Occupant Restraint Controller (ORC) Verification Test

2. CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE FRONT CONTROL MODULE (FCM)

With the scan tool, read Front Control Module (FCM) DTCs

Q: 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 ORC C1 and C2 connector.
Connect the 8443 - 24 ORC Adaptor to the ORC C2 connector.
Disconnect the Front Control Module (FCM) C1 connector.
Measure the resistance of the (D55) CAN B Bus (+) circuit between the Front Control Module C1 connector and the ORC C2 connector.

Q: Is the resistance below 2.0 ohms?

YES: Go To 4
NO: Repair the (D55) CAN B Bus (+) circuit for an open. Perform ORC VERIFICATION TEST - VER 1. Occupant Restraint Controller (ORC) Verification Test




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

Measure the resistance of the (D54) CAN B Bus (-) circuit between the Front Control Module C1 connector and the ORC C2 connector.

Q: Is the resistance below 2.0 ohms?

YES: Replace the ORC. Perform ORC VERIFICATION TEST - VER 1. Occupant Restraint Controller (ORC) Verification Test
NO: Repair the (D54) CAN B Bus (-) circuit for an open. Perform ORC VERIFICATION TEST - VER 1. Occupant Restraint Controller (ORC) Verification Test