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

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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 7P connector.
Disconnect the HandsFreeLink control unit 28P connector (see step 2 under HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ).
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.

Fig 1: Checking Continuity Between Handsfreelink Control Unit 28P Connector And Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

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.
Check for continuity between HandsFreeLink control unit 28P connector terminals No. 13 and No. 14 and HFL-navigation microphone 7P connector terminals No. 3 and No. 2 respectively.

Fig 2: Checking Continuity Between Handsfreelink Control Unit 28P Connector And HFL-Navigation Microphone 7P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 10.

NO -There is an open in the wires between the HandsFreeLink control unit and the HFL-navigation microphone. Replace the affected shielded harness.
Disconnect audio-navigation unit connector C (28P).
Check for continuity between body ground and HandsFreeLink control unit 28P connector terminals No. 27 and No. 28 individually.

Fig 3: Checking Continuity Between Body Ground And Handsfreelink Control Unit 28P Connector Terminals
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. 27 and No. 28 and audio-navigation unit connector C (28P) terminals No. 28 and No. 27 respectively.

Fig 4: Checking Continuity Between Handsfreelink Control Unit 28P Connector And Audio-Navigation Unit Connector C (28P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Substitute a known-good HandsFreeLink control unit (see HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ), and recheck. If the symptom/indication goes away, replace the original HandsFreeLink control unit (see HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ). If the symptom is still present, replace the 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.