Audio Communication Line Circuit Troubleshooting

Turn the ignition switch to LOCK (0).
Disconnect climate control unit connector B (12P) and audio unit connector D (20P).
Check for continuity between the following terminals of climate control unit connector B (12P)and audio-HVAC display unit connector D (20P).
12P: 20P:

No. 2 No. 8

No. 3 No. 7

Fig 1: Checking Continuity Between Terminals Of Climate Control Unit Connector B (12P)And Audio-HVAC Display Unit Connector D (20P
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 4.

NO -Repair an open in the wire between the climate control unit and the audio-HVAC display unit.
Check for continuity between body ground and climate control unit connector B (12P) terminals No. 2 and No. 3 individually.

Fig 2: Checking Continuity Between Body Ground And Climate Control Unit Connector B (12P) Terminals No. 2 And 3 Individually
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to body ground in the wire(s) between the climate control unit and the audio-HVAC display unit.

NO -Go to step 5.
Reconnect climate control unit connector B (12P).
Connect audio-HVAC display unit connector D (20P) terminals No. 7 and No. 8 with a jumper wire.

Fig 3: Identifying Audio-HVAC Display Unit Connector D (20P) Terminals No. 7 And 8 Connections Using Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to ON (II).
Press and hold the DEF button and FAN ON/OFF button.
Is the DEF button LED blinking?

YES -Audio-HVAC display unit is faulty, replace the audio-HVAC display unit (see AUDIO-HVAC DISPLAY UNIT REMOVAL/INSTALLATION ).

NO -Climate control unit is faulty, replace the climate control unit (see CLIMATE CONTROL UNIT REMOVAL/INSTALLATION ).