DTC B1776: Microphone Input/Output Shorted To Ground

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NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Connect the HDS to the DLC.
Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0) and then back to ON (II).
Check for DTCs with the HDS.
Is DTC B1776 indicated?

YES -Go to next step.

NO -Intermittent failure, the system is OK at this time.
Turn the ignition switch to LOCK (0).
Disconnect the front HFL-navigation-ANC/active sound control microphone 7P connector or the front HFL-ANC/active sound control microphone 7P connector.
Disconnect the HandsFreeLink control unit 28P connector.
Check for continuity between body ground and the HandsFreeLink control unit 28P connector terminals No. 1 and No. 2 individually, then between terminals No. 2 and No. 3.

Fig 1: Checking Continuity Between Body Ground And HandsFreeLink Control Unit 28P Connector Terminals No. 1 And No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -There is a short in the wire(s) between the HandsFreeLink control unit and the front HFL-navigation-ANC/active sound control microphone or the front HFL-ANC/active sound control microphone. Replace the affected shielded harness.

NO
- With navigation go to next step.
- Without navigation, substitute a known-good front HFL-ANC/active sound control microphone (see Front HFL-ANC/Active Sound Control Microphone Removal/Installation ), and recheck. If the symptom/indication goes away, replace the original front HFL-ANC/active sound control microphone (see Front HFL-ANC/Active Sound Control Microphone Removal/Installation ), if the symptom/indication is still present, replace the HandsFreeLink control unit (see HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ).
Disconnect navigation unit connector C (16P).
Check for continuity between HandsFreeLink control unit 28P connector terminals No 1 and No. 2 and front HFL-navigation-ANC/active sound control microphone 7P connector or front HFL-ANC/active sound control microphone 7P connector terminals No. 6 and No. 5 respectively.

Fig 2: Checking Continuity Between HandsFreeLink Control Unit 28P Connector Terminals No 1 And No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

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

NO -Go to next step.
Reconnect the HandsFreeLink control unit 28P connector and the front HFL-navigation-ANC/active sound control microphone 7P connector.
Turn the ignition switch ON (II).
Do the HFL Self-Diagnosis Function (see Self-Diagnostic Function ).
Do you hear the message "the hands free system is OK"?

YES -Replace the navigation unit (see NAVIGATION DISPLAY UNIT REMOVAL/INSTALLATION ).

NO -Substitute a known-good front HFL-navigation-ANC/active sound control microphone (see FRONT HFL-NAVIGATION-ANC/ACTIVE SOUND CONTROL MICROPHONE REMOVAL/INSTALLATION ), and recheck. If the symptom/indication goes away, replace the original front HFL-navigation-ANC/active sound control microphone (see FRONT HFL-NAVIGATION-ANC/ACTIVE SOUND CONTROL MICROPHONE REMOVAL/INSTALLATION ), if the symptom/indication is still present, replace the HandsFreeLink control unit (see HandsFreeLink Control Unit Removal/Installation ).