Without A/C

HVAC DTC Troubleshooting: 4

DTC indicator 4:

An Open or Short in the Mode Control Motor Circuit

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

2. Do the Self-Diagnostic Function with the heater control panel How To Troubleshoot The Heating System (Without A/C).

3. Check for DTCs.

Is DTC 4 indicated?

YES -

Go to step 4.

NO -

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

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

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

Is the mode control motor OK?

YES -

Go to step 6.

NO -

Replace the mode control motor Mode Control Motor Replacement.�

6. Disconnect the mode control motor 7P connector.

7. Disconnect the heater control panel 24P connector.

8. Check for continuity between following terminals of the heater control panel 24P connector and the mode control motor 7P connector.









Is there continuity?

YES -

Go to step 9.

NO -

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

9. Check for continuity between body ground and heater control panel 24P connector terminals No. 3, No. 4, No. 5, No. 6, and No. 13 individually.





Is there continuity?

YES -

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

NO -

Go to step 10.

10. Check for continuity between heater control panel 24P connector terminals as follows.





Is there continuity between any of the terminals?

YES -

Repair a short in the wire(s).�

NO -

Go to step 11.

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





Is there any voltage?

YES -

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

NO -

Check for loose wires or poor connections at the heater control panel 24P connector and at the mode control motor 7P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel Heater Control Panel Removal/Installation (Without A/C).�