DTC B1234 or DTC indicator B and A/C: A Short in the Air Mix Control Motor Circuit

WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. 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 (ID.
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 B1234 or B and A/C indicated?

YES -Go to step 5.

NO -Intermittent failure.
Turn the ignition switch to LOCK (0).
Test the air mix control motor (see AIR MIX CONTROL MOTOR TEST ).
Is the air mix control motor OK?

YES -Go to step 7.

NO -Replace the air mix control motor (see AIR MIX CONTROL MOTOR REPLACEMENT ).
Disconnect the air mix control motor 7P connector and humidity/in-car temperature sensor 4P connector.
Disconnect the climate control unit 36P connector.
Check for continuity between body ground and climate control unit 36P connector terminals No. 3 and No. 5 individually.

Fig 1: Checking Continuity Between Body Ground And Climate Control Unit 36P Connector Terminals No. 3 And No. 5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short to body ground in the wires between the climate control unit and the air mix control motor.

NO -Go to step 10.
Check for continuity between climate control unit 36P connector terminals No. 3 and No. 5.

Fig 2: Checking Continuity Between Climate Control Unit 36P Connector Terminals No. 3 And No. 5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short in the wires.

NO -Go to step 11.
Turn the ignition switch to ON (II), and check the same terminals for voltage to body ground.

Fig 3: Checking Voltage Between Climate Control Unit 36P Connector Terminals No. 3 And No. 5
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there any voltage?

YES -Repair a short to power in the wires between the climate control unit and the air mix control motor. This short may also damage the climate control unit. Repair the short to power before replacing the climate control unit.

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