B2991

DTC Troubleshooting: B2991

DTC B2991:

Climate Control Unit Lost Communication with Audio Unit

1. Clear the DTCs with the HDS.

2. Turn the ignition switch to LOCK (0) and then back to ON (II).

3. Do the self-diagnostic function with the HDS.

4. Check for DTCs.

Is DTC B2991 indicated?

YES -

Go to step 5.

NO -

Intermittent failure, check for loose wires or poor connections in the rear climate control panel and climate control unit circuit.�

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

6. Disconnect climate control unit connector B (14P).

7. Disconnect audio unit (without navigation) connector C (24P) or audio-navigation unit (with navigation) connector F (20P).

8. Check for continuity between climate control unit connector B (14P) terminal No. 8 and audio unit (without navigation) connector C (24P) terminal No. 24 or audio-navigation unit (with navigation) connector F (20P) terminal No. 10.

Without navigation





With navigation





Is there continuity?

YES -

Go to step 9.

NO -

Repair an open in the wire between the climate control unit and the audio unit (without navigation) or audio-navigation unit (with navigation).�

9. Check for continuity between climate control unit connector B (14P) terminal No. 8 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire between the climate control unit and the audio unit (without navigation) or audio-navigation unit (with navigation).�

NO -

Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit Climate Control Unit Removal/Installation. If the symptom/indication remains, substitute a known-good audio unit (without navigation) or audio-navigation unit (with navigation). If the symptom/indication goes away, replace the original audio unit (without navigation) Audio Unit Removal/Installation or the original audio-navigation unit (with navigation) Audio-Navigation Unit Removal/Installation.�