DTC B1780: HandsFreeLink steering wheel switch line short (without 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), then start the vehicle, and turn the steering wheel back and forth several times.
Check for DTCs with the HDS.
Is DTC B1780 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 REPLACEMENT ).
Disconnect the HandsFreeLink control unit 28P connector.
Disconnect the HFL switch 5P connector.
Check for continuity between HandsFreeLink control unit 28P connector terminal No. 13 and body ground.

Fig 1: Checking Continuity Between Handsfreelink Control Unit 28P Connector Terminal No. 13 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to body ground in the wire between the HandsFreeLink control unit and the HFL switch.

NO -Replace the HandsFreeLink control unit (see CONTROL UNIT INPUT TEST/REPLACEMENT ).