B2991

DTC Troubleshooting: B2991

DTC B2991: Climate Control Unit Lost Communication with Audio Unit

1. Clear the DTC with the HDS.

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

3. Do the self-diagnostic function with the HDS. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B2991 indicated?
YES - Go to step 5.

NO - Intermittent failure, check for loose wires or poor connections on 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 connector C (24P).

8. Check for continuity between climate control unit connector B (14P) terminal No. 8 and audio unit connector C (24P) terminal No. 24.

Is there continuity?
YES - Go to step 9.

NO - Repair open in the wire between the climate control unit and the audio unit.






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

Is there continuity?
YES - Repair short to body ground in the wire between the climate control unit and the audio unit.

NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit. If the symptom/indication remains, substitute a known-good audio unit. If the symptom/indication goes away, replace the original audio unit.