B1226

DTC Troubleshooting: B1226 (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 or the climate control unit.

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 -

With the humidity/in-car temperature sensor disconnected, 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 a 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 a 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 Climate Control Unit Removal/Installation.�