With Climate Control

DTC Troubleshooting: B1239 (A and MODE), B1239 (B and MODE)

DTC B1239 or DTC indicator A and MODE or B and MODE:

An Open or Short in the Mode Control Motor Circuit (Front)

1. Clear the DTCs with the HDS.

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

3. Do the Self-Diagnostic Function with the HDS or the climate control unit.

4. Check for DTCs.

Is DTC B1239, A and MODE or B and MODE indicated?

YES -

Go to step 5.

NO -

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

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

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

Is the front mode control motor OK?

YES -

Go to step 7.

NO -

Replace the front mode control motor Front Mode Control Motor Replacement.

7. Disconnect the front mode control motor 7P connector.

8. Disconnect climate control unit connector A (28P).

9. Check for continuity between the following terminals of climate control unit connector A (28P) and the front 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 front mode control motor.

10. Check for continuity between body ground and climate control unit connector A (28P) terminals No. 18, No. 19, No. 20, and No. 21 individually.





Is there continuity?

YES -

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

NO -

Go to step 11.

11. Check for continuity between climate control unit connector A (28P) terminals as follows.





Is there continuity between any of the terminals?

YES -

Repair a short in the wires between the climate control unit and the front mode control motor.

NO -

Go to step 12.

12. Turn the ignition switch to ON (II), and measure the voltage between body ground and climate control unit connector A (28P) terminals No. 18, No. 19, No. 20, and No. 21 individually.





Is there any voltage?

YES -

Repair a short to power in the wire(s) between the climate control unit and the front 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 (28P) and at the front 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 (With Climate Control).