B1776

Control System DTCs

DTC Troubleshooting: B1776

DTC B1776 : Microphone input/output shorted to ground

NOTE:
* Check the vehicle battery condition first Battery Test.
* Check the connectors for poor connections or loose terminals.

1. Problem verification:

Problem verification
-1. Check for HFL DTCs How To Troubleshoot The HandsFreeLink System.

Is DTC B1776 indicated?
-YES- The failure is duplicated, go to step 2.
-NO- Intermittent failure, the system is OK at this time.

2. Shorted wire check (MIC+ line):

Shorted wire check (MIC+ line)
-1. Disconnect the following connectors.





-2. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- There is a short to body ground in the wire between the HandsFreeLink control unit and the HFL microphone. Replace the affected shielded harness.
-NO- Go to step 3.

3. Shorted wire check (MIC+ line to another lines):

Shorted wire check (MIC+ line to another lines)
-1. Check for continuity between test points 1 and 2.














Is there continuity?
-YES- There is a short in the wires between the HandsFreeLink control unit and the HFL microphone. Replace the affected shielded harness.
-NO- Go to step 5.
-NO- Go to step 4.

4. HandsFreeLink control unit check:

HandsFreeLink control unit check
-1. Substitute a known-good HFL microphone (with moonroof) HFL Microphone Removal and Installation (Without Moonroof) or HFL microphone (without moonroof) HFL Microphone Removal and Installation (With Moonroof), and recheck.

Does the symptom/indication go away?
-YES- Replace the original HFL microphone.
-NO- Replace the HandsFreeLink control unit Service and Repair.

5. Shorted wire check (TELEM_SIG+ line):

Shorted wire check (TELEM_SIG+ line)
-1. Disconnect the following connector.





-2. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- There is a short to body ground in the wire between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.
-NO- Go to step 6.

6. Shorted wire check (TELEM_SIG+ line to TELEM_SIG- line):

Shorted wire check (TELEM_SIG+ line to another lines)
-1. Check for continuity between test points 1 and 2.














Is there continuity?
-YES- There is a short in the wires between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.
-NO- Go to step 7.

7. Determine possible failure area (audio-navigation unit, others):

Determine possible failure area (audio-navigation unit, others)
-1. Reconnect the HandsFreeLink control unit 32P connector and the HFL microphone 3P connector (with moonroof) or 10P connector (without moonroof).

-2. Turn the ignition switch to ON (II).

-3. Do the HFL Self-Diagnostic Function HandsFreeLink System Self-Diagnostic Function.

Do you hear, "The HFT is OK"?
-YES- Replace the audio-navigation unit Audio-Navigation Unit Removal and Installation.
-NO- Go to step 8.

8. HandsFreeLink control unit check:

HandsFreeLink control unit check
-1. Turn the ignition switch to LOCK (0).

-2. Substitute a known-good HFL microphone (with moonroof) HFL-Navigation Microphone Removal and Installation or HFL microphone (without moonroof) HFL Microphone Removal and Installation (With Moonroof), and recheck.

Does the symptom/indication go away?
-YES- Replace the original HFL microphone.
-NO- Replace the HandsFreeLink control unit Service and Repair.