Heating and Air Conditioning

DTC B1239 or DTC indicator 4: An Open or Short in the Mode Control Motor Circuit

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

Is DTC B1239 or 4 indicated?

YES - Go to step 4.

NO - Intermittent failure, check for loose wires or poor connections on the mode control motor circuits.

4. Turn the ignition switch OFF.
5. Test the mode control motor.

Is the mode control motor OK?

YES - Go to step 6.

NO - Replace the mode control motor.

6. Disconnect the mode control motor 7P connector.
7. Disconnect A/C control panel connector A (22P).




8. Check for continuity between the above terminals of A/C control panel connector A (22P) and the mode control motor 7P connector.

Is there continuity?

YES - Go to step 9.

NO - Repair any open in the wire(s) between the A/C control panel and the mode control motor.




9. Check for continuity between body ground and A/C control panel connector A (22P) terminals No. 3, 15, 16, 17, 18, 19, and 20 individually.

Is there continuity?

YES - Repair any short to body ground in the wire(s) between the A/C control panel and the mode control motor.

NO - Go to step 10.




10. Check for continuity between the terminals of A/C control panel connector A (22P) as follows.

Is there continuity between any of the terminals?

YES - Repair the short in the wires.

NO - Go to step 11.




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

Is there any voltage?

YES - Repair any short to power in the wire(s) between the A/C control panel and the mode control motor. This short may also damage the A/C control panel. Repair the short to power before replacing the A/C control panel.

NO - Check for loose wire or poor connections at A/C control panel connector A (22P) and at the mode control motor 7P connector. If the connections are good, substitute a known-good A/C control panel, and recheck. If the symptom/indication goes away, replace the original A/C control panel.