Operation CHARM: Car repair manuals for everyone.

B1240

DTC B1240 or DTC indicator B: A Problem in the Mode Control Linkage, Doors, or Motor

1. Clear the DTC with the HDS.
2. Turn the ignition switch OFF, and then ON (II).
3. Do the self-diagnostic with the HDS or climate control unit.
4. Check for DTCs.

Is DTC B1240 or B indicated?

YES - Go to step 5.

NO - Intermittent failure.

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

Is the mode control motor OK?

YES - Go to step 7.

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

7. Disconnect the mode control motor 7P connector.
8. Disconnect climate control unit connector A (24P).




9. Check for continuity between the terminals of climate control unit connector A (24P) and the mode control motor 7P connector.

Is there continuity?

YES - Go to step 10.

NO - Repair open in the wire(s) between the climate control unit and the mode control motor.




10. Check for continuity between body ground and climate control unit connector A (24P) terminals No. 7 and No. 8 individually.

Is there continuity?

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

NO - Substitute a known-good climate control unit and recheck. If the symptom/indication goes away, replace the original climate control unit.