DTC B121A or DTC indicator G and A/C ON: An Open in the Mode Control Motor Circuit

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 Honda Crosstour, 2014 Honda Crosstour, 2013 Honda Crosstour, 2012 Honda Crosstour, and 2011 Honda Accord Crosstour. 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 to ON (II).
Do the Self-Diagnostic Function with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the climate control unit (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS ).
Check for DTCs.
Is DTC B121A or G and A/C ON Indicated?

YES -Go to step 5.

NO -Intermittent failure. Check for loose wires or poor connections on the mode control motor circuit.
Turn the ignition switch to LOCK (0).
Test the mode control motor (see MODE CONTROL MOTOR TEST ).
Is the mode control motor OK?

YES -Go to step 7.

NO -Replace the mode control motor (see MODE CONTROL MOTOR REPLACEMENT ).
Disconnect the mode control motor 7P connector.
Disconnect climate control unit connectors A (28P) and B (12P).
Check for continuity between the following terminals of climate control unit connectors A (28P), B (12P), and the mode control motor 7P connector.
28P: 7P:

No. 4 No. 2

12P: 7P:

No. 7 No. 3

No. 9 No. 1

Fig 1: Checking For Continuity Between Terminals Of Climate Control Unit Connectors A (28P) And Mode Control Motor 7P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 2: Checking For Continuity Between Terminals Of Climate Control Unit Connectors B (12P) And Mode Control Motor 7P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for loose wires or poor connections at climate control unit connectors A (28P), B (12P), and at the mode control motor 7P connector. If the connections are good, substitute a known-good climate control unit and recheck. If the symptom/indication goes away, replace the original climate control unit; with navigation system (see WITH NAVIGATION SYSTEM ), without navigation system (see WITH NAVIGATION SYSTEM ).

NO -Repair an open in the wire(s) between the climate control unit and the mode control motor.