B155F-11

B155F-11-MICROPHONE 2 CIRCUIT (-) - CIRCUIT SHORT TO GROUND





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

Theory of Operation

The Hands Free Module (HFM) controls and monitors the (X723) microphone 2 input circuit (-) for a concern. The HFM communicates over the CAN-AT Bus. The microphone is located in the rearview mirror.

For a detailed description of the Hands Free System. Hands Free Module - Description.

For additional information regarding the operation of the Hands Free System. Hands Free Module - Operation.

- When Monitored:
With the ignition on.

- Set Condition:
The HFM detects a short to ground on the (X723) Microphone 2 IN (-) circuit for greater than 10 seconds.





1. CHECK FOR AN ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)

NOTE: Verify the connection of the inside rearview mirror harness connector.

1. Ignition on, engine not running.
2. With the scan tool, read the DTCs.

Does the scan tool display: B155F-11-MICROPHONE 2 CIRCUIT (-) - CIRCUIT SHORT TO GROUND 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 Inside Rearview Mirror harness connector.
3. Ignition on, engine not running.
4. Wait 20 seconds.
5. With the scan tool, read the active DTCs.

Does the scan tool display: B155F-11-MICROPHONE 2 CIRCUIT (-) - CIRCUIT SHORT TO GROUND as active?

Yes

- Go To 3

No

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

3. CHECK THE (X723) MICROPHONE 2 IN (-) CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the Hands Free Module harness connector.
3. Ignition on, engine not running.
4. Measure the resistance between ground and the (X723) Microphone 2 IN (-) circuit.

Is the resistance below 5 Ohms?

Yes

- Repair the short to ground in the (X723) Microphone 2 IN (-) circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

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