Auto Highbeam Module (AHBM)

U0020-CAN B BUS OFF PERFORMANCE

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

- 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, erase all 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 active: U0020-CAN B BUS OFF PERFORMANCE?

Yes

- Go To 2

No

- The condition that caused this symptom is currently not present. 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. Repair as necessary.
- 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 Inspection Perform the appropriate diagnostic procedure.

No

- Go To 3

3. (D55) CAN B BUS (+) CIRCUIT OPEN




1. Turn the ignition off.

NOTE: The Auto High Beam Module is part of the Right High Intensity Discharge Lamp.

2. Disconnect the Right High Intensity Discharge Lamp 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 Right High Intensity Discharge Lamp harness connector.

Does the Ohm meter read open circuit?

Yes

- Repair the (D55) Can B Bus (+) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 4

4. (D54) 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 Right High Intensity Discharge Lamp harness connector.

Does the Ohm meter read open circuit?

Yes

- Repair the (D54) Can B Bus (-) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Right High Intensity Discharge Lamp.
- Perform the BODY VERIFICATION TEST. Body Verification Test.