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. Make sure the ignition switch is in LOCK (0), or the vehicle ignition is in the OFF mode.

3. Do the self-diagnostic with the HDS Initial Inspection and Diagnostic Overview or the 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), or press the engine start/stop button to select the OFF mode.

6. Remove the 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 in-car temperature sensor.


7. Disconnect climate control unit connectors C (20P).

8. Check for continuity between climate control unit connector C (20P) terminal No. 15 and 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 C (20P) terminal No. 1 and in-car temperature sensor 4P connector terminal No. 3.

Is there continuity?
YES - Check for loose wires or poor connections at climate control unit connectors C (20P) and at the 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.