No Response From HFM (Hands Free Module)

NO RESPONSE FROM HFM (HANDS FREE MODULE)





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






1. TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

2. Turn the ignition on.

NOTE: Make sure the battery voltage is between 10.0 and 16.0 volts.

3. With the scan tool, read the module status.

NOTE: Check the Telematics Gateway (TGW) for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

- Go To 2

No

- The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE (A922) FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT




1. Turn the ignition off.
2. Disconnect the Hands Free Module C1 harness connector.
3. Using a 12-volt test light connected to ground, check the (A922) Fused B(+) circuit.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short in the (A922) Fused B(+) circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (Z911) GROUND CIRCUIT FOR AN OPEN




1. Using a 12-volt test light connected to 12-volts, check the (Z911) Ground circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open in the (Z911) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (D467) OR (D466) CAN AT BUS CIRCUIT FOR AN OPEN




1. Disconnect the TGW Module C2 harness connector.
2. Measure the resistance of the (D466) CAN AT Bus (-) circuit between the TGW Module C2 harness connector and the Hands Free Module harness connector.
3. Measure the resistance of the (D467) CAN AT Bus (+) circuit between the TGW Module C2 harness connector and the Hands Free Module harness connector.

Is resistance below 5.0 Ohms on both circuits?

Yes

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

No

- Repair the open in the (D467) or (D466) CAN AT Bus circuit. Inspect the connector for damage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.