DTC Troubleshooting: B1240 (J and A/C ON)
DTC B1240 or DTC indicator J and A/C ON:
 A Problem in the Mode Control Linkage, Doors, or Motor Circuit
  1. Turn the ignition switch to LOCK (0) and then to ON (II).
  1. Check for DTCs.
Is DTC B1240 or J and A/C ON indicated?
YES -
Go to Step 4 .
NO -
Intermittent failure, check for loose wires or poor connections on the mode control motor circuit.■
  1. Turn the ignition switch to LOCK (0).
Is the mode control motor OK?
YES -
Go to Step 6 .
NO -
Replace the mode control motor, or repair the mode control linkage or doors.■
  1. Disconnect the mode control motor 7P connector.
  1. Disconnect heater control unit connector A (28P).
  1. Check for continuity between the following terminals of heater control unit connector A (28P) and the mode control motor 7P connector.
    28P:
    7P:
    No. 7
    No. 2
    No. 8
    No. 1

Is there continuity?
YES -
Go to Step 9 .
NO -
Repair open in the wire(s) between the heater control unit and the mode control motor.■
  1. Check for continuity between body ground and heater control unit connector A (28P) No. 7 and No. 8 terminals individually.
Is there continuity?
YES -
Repair short to body ground in the wire(s) between the heater control unit and the mode control motor.■
NO -
Substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■