DTC Troubleshooting: B1780
DTC B1780:
 HFT-Voice Control Switch (HFT TALK/HFT BACK Buttons) Circuit 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 B1780 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. Check for continuity between Hands Free Telephone control unit the 22P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Repair short in the wire between the Hands Free Telephone control unit and the HFT control switch.■
NO -
Go to Step 9 .
  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 .■