B1240

Control System DTCs

DTC Troubleshooting: B1240 - (4B)

DTC B1240 or DTC indicator 4B : A Problem in the Mode Control Motor Circuit, Linkage, Doors, or Motor

1. Problem verification:

Problem verification
-1. Clear the DTCs with the HDS.

-2. Turn the ignition switch to LOCK (0), and then to ON (II).

-3. Do the self-diagnostic with the HDS or the climate control unit How To Troubleshoot The Climate Control System.

-4. Check for DTCs.

Is DTC B1240 or 4B indicated?
-YES- Go to step 2.
-NO- Intermittent failure. Check for loose wires or poor connections on the mode control motor circuit.

2. Open wire check (MODE_MTR_DEF/M-DEF, MODE_MTR_VENT/M-VENT lines):

Open wire check (MODE_MTR_DEF/M-DEF, MODE_MTR_VENT/M-VENT lines)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connectors.





-3. Check for continuity between test points 1 and 2 respectively.














Is there continuity?
-YES- The MODE_MTR_DEF/M-DEF and MODE_MTR_VENT/M-VENT wires are OK. Go to step 3.
-NO- Repair an open in the wire(s) between the climate control unit and the mode control motor.

3. Shorted wire check (MODE_MTR_DEF, MODE_MTR_VENT lines):

Shorted wire check (MODE_MTR_DEF, MODE_MTR_VENT lines)
-1. Check for continuity between test points 1 and 2 individually.














Is there continuity?
-YES- Repair a short to body ground in the wire between the climate control unit and the mode control motor.
-NO- The MODE_MTR_DEF and MODE_MTR_VENT wires are OK. Go to step 4.

4. Mode control motor check:

Mode control motor check
-1. Test the mode control motor Mode Control Motor Test.

Is the mode control motor OK?
-YES- Replace the climate control unit . Service and Repair
-NO- Replace the mode control motor Mode Control Motor Removal and Installation, or repair the mode control linkage or doors.