Hands Free Module (HFM)

U0019-CAN B BUS





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

- When Monitored:
Continuously

- Set Condition:
Whenever the CAN B Bus (+) or CAN B Bus (-) circuit is open, shorted to voltage or shorted to ground.





1. CHECK FOR ACTIVE DTCs
1. Turn the ignition on.
2. With the scan tool, read the active DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE TOTALLY INTEGRATED POWER MODULE (TIPM) DTCs
1. With the scan tool, read the Totally Integrated Power Module active DTCs.

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

Yes

- Testing and Inspection Perform the appropriate CAN B Bus diagnostic procedure.

No

- Go To 3

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




1. Turn the ignition off.
2. Disconnect the negative battery cable.
3. Disconnect the Hands Free Module harness connector.
4. Disconnect the Totally Integrated Power Module C3 harness connector.
5. Measure the resistance of the (D55) CAN B Bus (+) circuit between the Totally Integrated Power Module connector and the Hands Free Module connector.

Is the resistance below 2.0 Ohms?

Yes

- Go To 4

No

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

4. (D54) CAN B BUS (-) CIRCUIT OPEN




1. Measure the resistance of the (D54) CAN B Bus (-) circuit between the Totally Integrated Power Module connector and the Hands Free Module connector.

Is the resistance below 2.0 Ohms?

Yes

- Replace the Hands Free Module.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

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