DTC B2965: Climate Control Unit Lost Communication with Rear Climate Control Panel

WARNING: This page is about a different car, the 2009 Acura MDX, 2008 Acura MDX, and 2007 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

Clear the DTC with the HDS.
Turn the ignition switch to LOCK (0), and then ON (II).
Do the self-diagnostic with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ).
Check for DTCs.
Is DTC B2965 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.
Turn the ignition switch to LOCK (0).
Disconnect the rear climate panel 10P connector.
Turn the ignition switch to ON (II).
Measure the voltage between the rear climate control panel 10P connector No. 1 terminal and body ground.

Fig 1: Measuring Voltage Between Rear Climate Control Panel 10P Connector No. 1 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES - Go to step 9.

NO - Repair open in the wire between the No. 30 (10 A) fuse in the under-dash fuse/relay box and the rear climate control panel.
Turn the ignition switch to LOCK (0).
Check for continuity between the rear climate control panel 10P connector No. 3 terminal and body ground.

Fig 2: Identifying Continuity Between Rear Climate Control Panel 10P Connector No. 3 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 11.

NO - Check for an open in the wire between the rear climate control panel and body ground. If the wire is OK, check for poor ground at G506 (see GROUND TO COMPONENTS INDEX ).
Disconnect climate control unit connector B (14P).

Check for continuity between the following terminals of climate control unit connector B (14P) and the rear climate control panel 10P connector.

14P	10P
No. 11	No. 10
No. 12	No. 9

Fig 3: Identifying Continuity Between Climate Control Unit B (14P) And Rear Climate Control Panel 10P Connector Terminals

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 13.

NO - Repair open in the wire(s) between the climate control unit and the rear climate control panel.

Check for continuity between body ground and climate control unit connector B (14P) No. 11 and No. 12 terminals individually.

Fig 4: Identifying Continuity Between Body Ground And Climate Control Unit Connector B (14P) No. 11 And No. 12 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair short to body ground in the wire(s) between the climate control unit and the rear climate control panel.

NO - Go to step 14.
Check for continuity between climate control unit connector B (14P) No. 11 and No. 12 terminals.

Fig 5: Identifying Continuity Between Climate Control Unit Connector B (14P) No. 11 And No. 12 Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Repair short in the wires between the climate control unit and the rear climate control panel.

NO - Substitute a known-good rear climate control panel, and recheck. If the symptom/indication goes away, replace the original rear climate control panel.