Amplifier (AMP)

U0020-CAN B BUS OFF PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
Continuously.

- Set Condition:
Whenever the Can B Bus (+) or B Bus (-) circuit is open, shorted to voltage or shorted to ground, this code will set.





1. TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, record and erase DTCs
3. Cycle the ignition from on to off three times.
4. Turn the ignition on.
5. With the scan tool, read DTCs.

Does the scan tool display U0020-CAN B BUS OFF PERFORMANCE?

Yes

- Go To 2

No

- The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK FRONT CONTROL MODULE DTCs
1. With the scan tool, read Front Control Module DTCs

Does the scan tool display any CAN B BUS DTCs - ACTIVE?

Yes

- Testing and InspectionPerform the appropriate diagnostic procedure.

No

- Go To 3

3. CAN B BUS (+) CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the Amplifier C2 harness connector.
3. Disconnect the Front Control Module C1 harness connector.
4. Measure the resistance of the (D55) Can B Bus (+) circuit between the Front Control Module C1 harness connector and the Amplifier C2 harness connector.

Is the resistance below 2.0 Ohms?

Yes

- Go To 4

No

- Repair the Can B Bus (+) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CAN B BUS (-) CIRCUIT OPEN




1. Measure the resistance of the (D54) Can B Bus (-) circuit between the Front Control Module C1 harness connector and the Amplifier C2 harness connector.

Is the resistance below 2.0 Ohms?

Yes

- Replace the Amplifier.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Repair the Can B Bus (-) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.