DTC B1776: Microphone input/output shorted to ground or open (with navigation)

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 (see HOW TO CHECK FOR DTCS WITH THE HDS ).
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 step 5.

NO -Intermittent failure, the system is OK at this time.
Turn the ignition switch to LOCK (0).
Disconnect the HFL-navigation microphone 10P connector.
Disconnect the HandsFreeLink control unit 28P connector.
Check for continuity between body ground and 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, 2 And No. 2, 3
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 HFL-navigation microphone. Replace the affected shielded harness.

NO -Go to step 9.
Check for continuity between HandsFreeLink control unit 28P connector terminals No. 1 and No. 2 and HFL-navigation microphone 10P connector terminals No. 4 and No. 5 respectively.

Fig 2: Checking Continuity Between Handsfreelink Control Unit 28P Connector Terminals No. 1, 2 And HFL-Navigation Microphone 10P Connector Terminals No. 4, 5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

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.
Remove the audio-navigation unit (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ), and disconnect audio-navigation unit connector D (12P).
NOTE:
- Eject all the audio discs before removing the audio-navigation unit to prevent damaging the CD player's load mechanism.
- Remove the PC card before removing the audio-navigation unit.
Check for continuity between body ground and HandsFreeLink control unit 28P connector terminals No. 15 and No. 16 individually.

Fig 3: Checking Continuity Between Body Ground And Handsfreelink Control Unit 28P Connector Terminals No. 15 And 16
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -There is a short to body ground in the wires between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.

NO -Go to step 12.
Check for continuity between HandsFreeLink control unit 28P connector terminals No. 15 and No. 16 and audio-navigation unit connector D (12P) terminals No. 12 and No. 11 respectively.

Fig 4: Checking Continuity Between Handsfreelink Control Unit 28P Connector Terminals No. 15, 16 And Audio-Navigation Unit Connector D (12P) Terminals No. 12, 11
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Substitute a known-good HandsFreeLink control unit (see CONTROL UNIT INPUT TEST/REPLACEMENT ), and recheck. If the symptom goes away, replace the original HandsFreeLink control unit (see CONTROL UNIT INPUT TEST/REPLACEMENT ). If the symptom does not go away, replace the faulty audio-navigation unit (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ).

NO -There is an open in the wires between the HandsFreeLink control unit and the audio-navigation unit. Replace the affected shielded harness.