B

DTC Troubleshooting: B1240 or Indicator B

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 to LOCK (0), and then to ON (II).

3. Do the self-diagnostic with the HDS Initial Inspection and Diagnostic Overview or climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1240 or B indicated?
YES - Go to step 5.

NO - Intermittent failure.


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

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

Is the mode control motor OK?
YES - Go to step 7.

NO - Replace the mode control motor, Mode Control Motor Replacement 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 following 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) No. 7 and No. 8 terminals 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.