B1239

DTC Troubleshooting: B1239 (M)

DTC B1239 or DTC indicator M:

An Open or Short in the Mode Control Motor Circuit

1. Clear the DTC with the HDS.

2. Turn the ignition switch to LOCK (0), and then turn to ON (II).

3. Do the self-diagnostic function with the HDS Initial Inspection and Diagnostic Overview or climate control unit Initial Inspection and Diagnostic Overview.

4. Check for DTCs.

Is DTC B1239 or M indicated?

YES -

Go to step 5.

NO -

Intermittent failure. Check for loose wires or poor connections on the mode control motor circuit.�

5. Turn the ignition switch to LOCK (0).

6. Test the mode control motor Mode Control Motor Test.

Is the mode control motor OK?

YES -

Go to step 7.

NO -

Replace the mode control motor Mode Control Motor Replacement.�

7. Disconnect the mode control motor 7P connector.

8. Disconnect climate control unit connector A (32P).

9. Check for continuity between the following terminals of climate control unit connector A (32P) and the mode control motor 7P connector.









Is there continuity?

YES -

Go to step 10.

NO -

Repair an open in the wire(s) between the climate control unit and the mode control motor.�

10. Check for continuity between body ground and climate control unit connector A (32P) terminals No. 20, 21, 22, and No. 23 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the climate control unit and the mode control motor.�

NO -

Go to step 11.

11. Check for continuity between climate control unit connector A (32P) terminals as follows.





Is there continuity between any of the terminals?

YES -

Repair a short in the wires.�

NO -

Go to step 12.

12. Turn the ignition switch to ON (II), and measure the same terminals for voltage between the terminals and body ground.





Is there any voltage?

YES -

Repair a short to power in the wire(s) between the climate control unit and the mode control motor. This short may also damage the climate control unit. Repair a short to power before replacing the climate control unit.�

NO -

Check for loose wires or poor connections at climate control unit connector A (32P) 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 Climate Control Unit Removal/Installation.�