DTC Troubleshooting: B1780
DTC B1780:
 HFT-Voice Control Switch (HFT TALK/HFT BACK Buttons) Circuit Short to Ground
  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 B1780 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time.■
  1. Turn the ignition switch to LOCK (0).
  1. Do the HFT-voice control switch test.
Is the switch OK?
YES -
Go to Step 7 .
NO -
Replace the HFT-voice control switch. ■
  1. Turn the ignition switch to LOCK (0).
  1. Remove the driver's dashboard lower cover.
  1. Disconnect the Hands Free Telephone control unit 28P connector.
  1. Disconnect the HFT-voice control switch 5P connector.
  1. Check for continuity between Hands Free Telephone control unit 28P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Repair short in the wire.■
NO -
Replace the Hands Free Telephone control unit. ■