B and Auto

DTC Troubleshooting: B1226 or Indicator B and AUTO

DTC B1226 or DTC indicator B and AUTO:A Short 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 function with the HDS Initial Inspection and Diagnostic Overview or the climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1226 or B 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 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 C (20P).

8. Check for continuity between climate control unit connector C (20P) terminal No. 15 and body ground.

Is there continuity?
YES - Repair short to body ground in the wire between the climate control unit and the in-car temperature sensor.

NO - Go to step 9.






9. Check for continuity between climate control unit connector C (20P) terminals No. 1 and No. 15.

Is there continuity?
YES - Repair short in the wires between the climate control unit and the in-car temperature sensor.

NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.