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DTC Troubleshooting: B1779

DTC B1779: HandsFreeLink steering wheel switch failure (without navigation)

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN system diagnosis test mode A.

- Check the vehicle battery condition first 12 Volt Battery Test.
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN system diagnosis test mode A Troubleshooting - B-CAN System Diagnosis Test Mode A.

1. Connect the HDS to the DLC.

2. Clear the DTCs with the HDS.

3. Turn the ignition switch to LOCK (0), then start the engine and turn the steering wheel from lock to lock several times.

4. 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.

5. Turn the ignition switch to LOCK (0).

6. Do the HFL switch test.

Is the switch OK?

YES -

Go to step 7.

NO -

Replace the HFL switch HFL Switch Replacement.

7. Disconnect the HandsFreeLink control unit 28P connector.

8. Disconnect the HFL switch 5P connector, then reconnect the cable reel subharness 20P connector.

9. Turn the ignition switch to ON (II).

10. Measure the voltage between HFL switch 5P connector terminal No. 3 and body ground.





Is there battery voltage?

YES -

Go to step 11.

NO -

Go to step 15.

11. Turn the ignition switch to LOCK (0).

12. Substitute a known-good cable reel Service and Repair.

13. Turn the ignition switch to ON (II).

14. Measure the voltage between HFL switch 5P connector terminal No. 3 and body ground.





Is there battery voltage?

YES -

Repair a short to power in the wire between the HandsFreeLink control unit, the cable reel, and the HFL switch.

NO -

Replace the original cable reel.

15. Turn the ignition switch to LOCK (0).

16. Check for continuity between HandsFreeLink control unit 28P connector terminal No. 2 and HFL switch 5P connector terminal No. 3.





Is there continuity?

YES -

Go to step 18.

NO -

Go to step 17.

17. Substitute a known-good cable reel Service and Repair, and check for continuity between HandsFreeLink control unit 28P connector terminal No. 2 and HFL switch 5P connector terminal No. 3.





Is there continuity?

YES -

Replace the original cable reel Service and Repair.

NO -

Repair an open in the wire between the HFL switch, the cable reel, and the HandsFreeLink control unit.

18. Remove the audio unit Audio Unit Removal / Installation, and disconnect audio unit connector A (24P).

19. Check for continuity between HFL switch 5P connector terminal No. 4 and audio unit connector A (24P) terminal No. 5.





Is there continuity?

YES -

Replace the HandsFreeLink control unit.

NO -

Go to step 20.

20. Substitute a known-good cable reel Service and Repair, and check for continuity between HFL switch 5P connector terminal No. 4 and audio unit connector A (24P) terminal No. 5.





Is there continuity?

YES -

Replace the original cable reel Service and Repair.

NO -

Repair an open in the wire between the HFL switch, the cable reel, and the audio unit.