Heating and Air Conditioning

DTC B1240 or DTC indicator 5: A Problem in the Mode Control Linkage, Doors, 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 self-diagnostic.

Is DTC B1240 or 5 indicated?

YES - Go to step 4.

NO - Intermittent failure.

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

Is the mode control motor OK?

YES - Substitute a known-good HVAC control unit, and recheck. If the symptom/indication goes away, replace the original HVAC control unit.

NO - Replace the mode control motor, or repair the mode control linkage or doors.