DTC Troubleshooting: B1234 (K)

DTC B1234 or DTC indicator K:  A Short in the Air Mix Control Motor Circuit

1.Clear the DTC with the HDS.

2.Turn the ignition switch OFF, and then ON (II).

3.Do the self-diagnostic with the HDS or climate control unit.

4.Check for DTCs.

Is DTC B1234 or K indicated?


YES - Go to 5.


NO - Intermittent failure.n


5.Turn the ignition switch OFF.

6.Test the air mix control motor.

Is the air mix control motor OK?


YES - Go to 7.


NO - Replace the air mix control motor.n


7.Disconnect the air mix control motor 7P connector.

8.Disconnect the climate control unit 32P connector.

9.Check for continuity between body ground and the climate control unit 32P connector terminals No. 7, 9, 11, 19 and 27 individually.

 

Is there continuity?


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


NO - Go to 10.


10.Check for continuity between the climate control unit 32P connector terminals as follows.

From terminal To terminals 
9, 11, 19, 27 
11, 19, 27 
11 19, 27 
19 27 

Is there continuity between any of the terminals?


YES - Repair the short in the wires.n


NO - Go to 11.

11.Turn the ignition switch ON (II), and check the same terminals for voltage to body ground.

 

Is there battery voltage?


YES - Repair any 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.n


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