DTC B1779: HandsFreeLink steering wheel switch failure (without 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), then start the engine and turn the steering wheel from lock to lock several times.
Check for DTCs with the HDS.
Is DTC B1779 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time.
Turn the ignition switch to LOCK (0).
Do the HFL switch test (see HFL SWITCH TEST ).
Is the switch OK?

YES -Go to step 7.

NO -Replace the HFL switch (see HFL SWITCH TEST ).
Disconnect the HandsFreeLink control unit 28P connector (see step 2 under HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ).
Disconnect the dashboard wire harness 20P connector from the cable reel.
Turn the ignition switch to ON (II).
Measure the voltage between HandsFreeLink control unit 28P connector terminal No. 2 and body ground.

Fig 1: Measuring Voltage Between Handsfreelink Control Unit 28P Connector Terminal No. 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Repair a short to power in the BLU wire.

NO -Go to step 11.
Turn the ignition switch to LOCK (0).
Check for continuity between HandsFreeLink control unit 28P connector terminal No. 2 and dashboard wire harness 20P connector terminal No. 5.

Fig 2: Checking Continuity Between Handsfreelink Control Unit 28P Connector And Dashboard Wire Harness 20P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 13.

NO -Repair an open in the wire between the cable reel and the HandsFreeLink control unit.
Check for continuity between audio unit connector B (32P) terminal No. 3 and dashboard wire harness 20P connector terminal No. 19.

Fig 3: Checking Continuity Between Audio Unit Connector B (32P) And Dashboard Wire Harness 20P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for loose or poor connections at the audio unit, HandsFreeLink control unit, and HFL switch. If the connections are OK, substitute a known-good HandsFreeLink control unit (see HANDSFREELINK CONTROL UNIT REMOVAL/INSTALLATION ). 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 cable reel (see CABLE REEL REPLACEMENT ).

NO -Repair an open in the wire between the cable reel and the audio unit.