DTC Troubleshooting: B1238 (F and A/C ON)
DTC B1238 or DTC indicator F and A/C ON:
 A Problem in the Passenger's Air Mix Control Linkage, Door, or Motor Circuit
  1. Clear the DTC with the HDS.
  1. Turn the ignition switch to LOCK (0) and then to ON (II).
  1. Do the self-diagnostic function with the HDS or the heater control unit.
  1. Check for DTCs.
Is DTC B1238 or F and A/C ON indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure; check for loose wires or poor connections on the passenger's air mix control motor circuit.■
  1. Turn the ignition switch to LOCK (0).
  1. Test the passenger's air mix control motor.
Is the passenger's air mix control motor OK?
YES -
Go to Step 7 .
NO -
Replace the passenger's air mix control motor, or repair the passenger's air mix control linkage or door.■
  1. Disconnect the passenger's air mix 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 passenger's air mix control motor 7P connector.
    28P:
    7P:
    No. 1
    No. 2
    No. 2
    No. 1

Is there continuity?
YES -
Go to Step 10 .
NO -
Repair open in the wire(s) between the heater control unit and the passenger's air mix control motor.■