Audio/Video

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.

POSSIBLE CAUSES
- CAN B BUS DTCs in the totally integrated power module
- (D54) CAN B BUS (-) circuit open
- (D55) CAN B BUS (+) circuit open
- Amplifier

Diagnostic Test

1. TEST FOR INTERMITTENT CONDITION

Turn the ignition on.
With the scan tool, record and erase DTCs.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read DTCs.

Q: 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 - VER 1. Body Verification Test

2. CHECK FRONT CONTROL MODULE DTCs

With the scan tool, read Totally Integrated Power Module DTCs.

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

YES: Refer to Manufacturer Code Charts for problems related to Communication.
NO: Go to 3




3. CAN B BUS (+) CIRCUIT OPEN

Turn the ignition off.
Disconnect the Amplifier C1 harness connector.
Disconnect the Totally Integrated Power Module C3 harness connector.
Measure the resistance of the (D55) CAN B BUS (+) circuit between the Totally Integrated Power module C3 harness connector and the Amplifier C1 harness connector.

Q: Is the resistance below 2.0 ohms?

YES: Go To 4 Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the CAN B BUS (+) circuit for an open. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




4. CAN B BUS (-) CIRCUIT OPEN

Measure the resistance of the (D54) CAN B BUS (-) circuit between the Totally Integrated Power Module C3 harness connector and the Amplifier C1 harness connector.

Q: Is the resistance below 2.0 ohms?

YES: Replace the Amplifier. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the CAN B BUS (-) circuit for an open. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test