B and AUTO

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 DTCs with the HDS.

2. Turn the ignition switch to LOCK (0) and then back to ON (II).

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 in the in-car temperature sensor circuit.

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

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

Is the in-car temperature sensor OK?

YES -

With the in-car temperature sensor disconnected, go to step 7.

NO -

Replace the humidity/in-car temperature sensor Humidity/In-Car Temperature Sensor Replacement.

7. Disconnect the climate control unit 36P connector.

8. Check for continuity between climate control unit 36P connector terminal No. 20 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 36P connector terminals No. 1 and No. 20.





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.