Diesel Data: Automotive Repair

Audio Communication Line Circuit Troubleshooting (With Climate Control)




Audio Communication Line Circuit Troubleshooting

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

2. Disconnect climate control unit connector A (28P) and the audio-HVAC subdisplay (with navigation) or audio-HVAC display unit (without navigation) 12P connector.

3. Check for continuity between the following terminals of climate control unit connector A (28P) and the audio-HVAC subdisplay or display unit 12P connector.





Is there continuity?
YES - Go to step 4.

NO - Repair open in the wire between climate control unit connector A (28P) and the audio-HVAC subdisplay or display unit 12P connector.






4. Check for continuity between body ground and climate control unit connector A (28P) No. 19 and No. 20 terminals individually.

Is there continuity?
YES - Repair short to body ground in the wire between climate control unit connector A (28P) and the audio-HVAC control unit 12P connector.

NO - Go to step 5.






5. Reconnect climate control unit connector A (28P).

6. Connect the audio-HVAC subdisplay or display unit 12P connector No. 7 and No. 8 terminals with a jumper wire.

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

8. Press and hold the DEF button and OFF button.

Is the DEF button LED blinking?
YES - Audio-HVAC subdisplay unit or display unit is faulty, replace the audio-HVAC subdisplay unit Audio-HVAC Subdisplay Unit Removal/Installation (With Navigation) or audio-HVAC display unit. Audio-HVAC Display Unit Removal/Installation (Without Navigation)

NO - Climate control unit is faulty, replace the climate control unit. Climate Control Unit Removal/Installation (With Navigation)