Amplifier (AMP)
U0020-CAN B BUS OFF PERFORMANCE
- 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 3 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
- Diagnose and repair the DTC(s). Testing and Inspection.
No
- Go To 3
3. CAN B BUS (+) CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the Amplifier 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 harness connector.
Does the ohm meter read open circuit?
Yes
- Repair the Can B Bus (+) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
No
- Go To 4
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 harness connector.
Does the ohm meter read open circuit?
Yes
- Repair the Can B Bus (-) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
No
- Replace the Amplifier.
- Perform the BODY VERIFICATION TEST. Body Verification Test.