DTC Troubleshooting: B1779
DTC B1779:
 HFT-Voice Control Switch (HFT TALK/HFL BACK Buttons) Circuit Open/Short to Power
  1. Connect the HDS to the DLC.
  1. Clear the DTCs with the HDS.
  1. Turn the ignition switch to LOCK (0), then start the vehicle and turn the steering wheel back and forth several times.
  1. 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.■
  1. Turn the ignition switch to LOCK (0).
Is the switch OK?
YES -
Go to Step 7 .
NO -
  1. Disconnect Hands Free Telephone control unit 28P connector.
  1. Disconnect HFT-voice control switch 5P connector.
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage of the HFL-Voice Control switch connector (5P) terminal No. 3 to body ground.
Is there voltage?
YES -
Repair a short to power on GRY wire.■
NO -
Go to Step 12 .
  1. Check for continuity between Hands Free Telephone control unit 28P connector terminal No. 2 and HFT-voice control switch 5P connector terminal No. 3.
Is there continuity?
YES -
Go to Step 13 .
NO -
Repair open in the GRY wire between the switch, the cable reel, and the Hands Free Telephone control unit.■
  1. Turn the ignition switch to ON (II).
  1. Measure the voltage between Hands Free Telephone control unit 28P connector terminal No. 2 and body ground.
Is there voltage?
YES -
Repair short to body ground in the wire between the Hands Free Telephone control unit and the HFT-voice control switch.■
NO -
Go to Step 15 .
  1. Turn the ignition switch to LOCK (0).
  1. Check for continuity between HFT-voice control switch connector (5P) terminal No. 4 and body ground.
Is there continuity?
YES -
NO -
Repair open in the wire between the switch, cable reel, and the audio unit.■