B1776

DTC Troubleshooting: B1776

DTC B1776: Microphone input/output shorted to ground or open

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN system diagnosis test mode A.

1. Connect the HDS to the DLC.

2. Clear the DTCs with the HDS.

3. Turn the ignition switch to LOCK (0), and then back to ON (II).

4. Check for DTCs with the HDS.

Is DTC B1776 indicated?

YES -

Go to step 5.

NO -

Intermittent failure, the system is OK at this time.�

5. Turn the ignition switch to LOCK (0).

6. Disconnect the HFL-navigation microphone 3P connector.

7. Disconnect the HandsFreeLink control unit 28P connector.

8. Check for continuity between body ground and HandsFreeLink control unit 28P connector terminals No. 13 and No. 14 individually, then between terminals No. 12 and No. 13.





Is there continuity?

YES -

There is a short in the wires between the HandsFreeLink control unit and the HFL-navigation microphone. Replace the affected shielded harness.�

NO -

Go to step 9.

9. Check for continuity between HandsFreeLink control unit 28P connector terminals No. 13 and No. 14 and HFL-navigation microphone 3P connector terminals No. 1 and No. 2 respectively.





Is there continuity?

YES -

Go to step 10.

NO -

There is an open in the wire(s) between the HandsFreeLink control unit and the HFL-navigation microphone. Replace the affected shielded harness.�

10. Remove the audio-navigation unit Audio-Navigation Unit Removal/Installation, and disconnect audio-navigation unit connector D (12P).

11. Check for continuity between body ground and HandsFreeLink control unit 28P connector terminals No. 27 and No. 28 individually.





Is there continuity?

YES -

There is a short to body ground in the wire(s) between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.�

NO -

Go to step 12.

12. Check for continuity between HandsFreeLink control unit 28P connector terminals No. 27 and No. 28 and audio-navigation unit connector D (12P) terminals No. 8 and No. 7 respectively.





Is there continuity?

YES -

Substitute a known-good HandsFreeLink control unit Service and Repair, and recheck. If the symptom goes away, replace the original HandsFreeLink control unit Service and Repair. If the symptom does not go away, replace the audio-navigation unit.�

NO -

There is an open in the wire(s) between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.�