A and Auto

DTC Troubleshooting: B1225 or Indicator A and AUTO

DTC B1225 or DTC indicator A and AUTO:An Open in the In-car Temperature Sensor Circuit

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 function with the HDS Initial Inspection and Diagnostic Overview or climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1225 or A and AUTO indicated?
YES - Go to step 5.

NO - Intermittent failure, check for loose wires or poor connections on the in-car temperature sensor circuit.


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

6. Remove the humidity/in-car temperature sensor, Service and Repair and test it. Humidity/In-Car Temperature Sensor Test

Is the in-car temperature sensor OK?
YES - Go to step 7.

NO - Replace the humidity/in-car temperature sensor.


7. Disconnect climate control unit connector A (40P).

8. Check for continuity between climate control unit connector A (40P) terminal No. 5 and the humidity/in-car temperature sensor 4P connector terminal No. 4.

Is there continuity?
YES - Go to step 9.

NO - Repair open in the wire between the climate control unit and the in-car temperature sensor.






9. Check for continuity between climate control unit connector A (40P) terminal No. 8 and the humidity/in-car temperature sensor 4P connector terminal No. 3.

Is there continuity?
YES - Check for loose wires or poor connections at climate control unit connector A (40P) and at the humidity/in-car temperature sensor 4P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.

NO - Repair open in the wire between the climate control unit and the in-car temperature sensor.