Without Climate Control

DTC Troubleshooting: B1235 (3)

DTC B1235 or DTC indicator 3:

A Problem in the Air Mix Control motor circuit, Linkage, Door, or Motor

1. Clear the DTC with the HDS.

2. Operate the heater-A/C control system in several modes.

3. Check for DTCs using the HDS or the self-diagnostic function.

Is DTC B1235 or 3 indicated?

YES -

Go to step 4.

NO -

Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.

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

5. Test the air mix control motor Air Mix Control Motor Test (Without Climate Control).

Is the air mix control motor OK?

YES -

Go to step 6.

NO -

Replace the air mix control motor Air Mix Control Motor Replacement (Without Climate Control), or repair the air mix control linkage or door.

6. Disconnect the air mix control motor 7P connector.

7. Disconnect the HVAC control unit 30P connector.

8. Check for continuity between the following terminals of the HVAC control unit 30P connector and the air mix control motor 7P connector.









Is there continuity?

YES -

Go to step 9.

NO -

Repair an open in the wire(s) between the HVAC control unit and the air mix control motor.

9. Check for continuity between body ground and HVAC control unit 30P connector terminals No. 18 and No. 19 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the HVAC control unit and the air mix control motor.

NO -

Substitute a known-good HVAC control unit HVAC Control Unit Removal/Installation (Without Climate Control), and recheck. If the symptom/indication goes away, replace the original HVAC control unit HVAC Control Unit Removal/Installation (Without Climate Control).