B1237

DTC B1237 or DTC indicator M: A Short in the Passenger's Air Mix Control Motor Circuit

1. Clear the DTC by turning the ignition switch OFF, and then ON (II).
2. Operate the climate control system in several modes.
3. Check for DTCs using the self-diagnostic or HDS.

Is DTC B1237 or M indicated?

YES - Go to step 4.

NO - Intermittent failure.

4. Turn the ignition switch OFF.
5. Test the passenger's air mix control motor,

Is the passenger's air mix control motor OK?

YES - Go to step 6.

NO - Replace the passenger's air mix control motor.

6. Disconnect the passenger's air mix control motor 5P connector.
7. Disconnect climate control unit connector A (20P) and B (16P).







8. Check for continuity between body ground and climate control unit connector A (20P) terminals No. 5 and 20 individually, and between body ground and climate control unit connector B (16P) terminals No. 7, 8 and 16 individually.

Is there continuity?

YES - Repair any short to body ground in the wire(s) between the climate control unit and the passenger's air mix control motor.

NO - Go to step 9.




9. Check for continuity between the terminals of climate control unit connector A (20P) and B (16P) as follows.

Is there continuity between any of the terminals?

YES - Repair the short in the wires.

NO - Go to step 10.




10. Turn the ignition switch ON (II), and check the same terminals for voltage.

Is there any voltage?

YES - Repair any short to power in the wire(s) between the climate control unit and the passenger's 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.