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. Turn the ignition switch to LOCK (0), and then back to ON (II), or press the engine start/stop button to select the OFF mode, and then the ON 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 Service and Repair.�

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 Service and Repair.�