DTC Troubleshooting: B1779
DTC B1779:
 HFT Switch or HFT-Voice Control Switch (HFT TALK/HFT BACK Buttons) Circuit Open/Short
  1. Clear the DTCs with the HDS.
  1. Turn the ignition switch OFF, 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 4 .
NO -
Intermittent failure, the system is OK at this time.■
  1. Turn the ignition switch OFF.
Is the switch OK?
YES -
Go to Step 6 .
NO -
  1. Disconnect the 22P connector from the Hands Free Telephone control unit.
  1. Disconnect the 5P connector from the HFT-voice control switch.
  1. Check for continuity between the Hands Free Telephone control unit 22P connector terminal No. 2 and HFT-voice control switch 5P connector terminal No. 3.
Is there continuity?
YES -
Go to Step 12 .
NO -
Repair an open in the YEL or GRY wire between the switch, cable reel, and Hands Free Telephone control unit.■
  1. Turn the ignition switch ON (II).
  1. Check for voltage between Hands Free Telephone control unit the 22P connector terminal No. 2 and body ground.
Is there voltage?
YES -
Repair short in the wire between the Hands Free Telephone control unit and the HFT control switch.■
NO -
Go to Step 14 .
  1. Turn the ignition switch OFF.
  1. Check for continuity between HFT control switch the 5P connector terminal No. 4 and body ground.
Is there voltage?
YES -
Go to Step 16 .
NO -
Repair open in the wire between the switch, cable reel, and the audio unit or poor ground (G505).■
  1. Reconnect the Hands Free Telephone control unit 22P connector.
  1. Turn the ignition switch ON (II).
  1. Check for voltage between Hands Free Telephone control unit the 22P connector terminal No. 2 and body ground.
Is there voltage?
YES -
Replace the Hands Free Telephone control unit .■
NO -
Check the No. 35 (7.5 A) fuse in the under-dash fuse/relay box. If the fuse is OK, check for an open in the wire between the under-dash fuse/relay box and the Hands Free Telephone control unit. If the fuse is OK, replace the Hands Free Telephone control unit .■