B1235

DTC Troubleshooting: B1235 (L and AUTO)

DTC B1235 or DTC indicator L and AUTO:

A Problem in the Driver's Air Mix Control Linkage, Door, or Motor Circuit

1. Clear the DTC 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. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1235 or L and AUTO indicated?

YES -

Go to step 5.

NO -

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

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

6. Test the driver's air mix control motor Driver's Air Mix Control Motor Test (With Climate Control).

Is the driver's air mix control motor OK?

YES -

Go to step 7.

NO -

Replace the driver's air mix control motor Driver's Air Mix Control Motor Replacement (With Climate Control), or repair the driver's air mix control linkage or door.�

7. Disconnect the driver's air mix control motor 7P connector.

8. Disconnect the climate control unit 36P connector.

9. Check for continuity between the following terminals of the climate control unit 36P connector and the driver's air mix 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 driver's air mix control motor.�

10. Check for continuity between body ground and climate control unit 36P connector terminals No. 30 and No. 31 individually.





Is there continuity?

YES -

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

NO -

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.�