Hands Free Module (HFM)

B143F-MICROPHONE 2 CIRCUIT HIGH





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

Theory of Operation

The Hands Free Module (HFM) controls and monitors the (X722) microphone 2 input circuit (+) for a concern. The microphone is located in the rearview mirror.

For a detailed description of the Hands Free System. Navigation/Telecommunication - Description.

For additional information regarding the operation of the Hands Free System. Navigation/Telecommunication - Operation.

- When Monitored:
With the ignition on.

- Set Condition:
The Hands Free Module (HFM) detects a short to voltage on the (X722) Microphone 2 IN (+) circuit.





1. CHECK FOR ACTIVE DTC

NOTE: Verify the connection of the Rearview Mirror harness connector.

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

Does the scan tool display B143F-MICROPHONE 2 CIRCUIT HIGH as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE INSIDE REARVIEW MIRROR




1. Turn the ignition off.
2. Disconnect the Rearview Mirror harness connector.
3. Turn the ignition on.
4. With the scan tool, read the active DTCs.

Does the scan tool display B143F-MICROPHONE 2 CIRCUIT HIGH as active?

Yes

- Go To 3

No

- Replace the Rearview Mirror. Interior Rearview Mirror - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (X722) MICROPHONE CIRCUITS FOR A SHORT TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the Hands Free Module harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (X722) Microphone circuit.

Is the voltage above 1.0 volt?

Yes

- Repair the (X722) Microphone circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

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