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).

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).

6. Remove the in-car temperature sensor Service and Repair, and test it Testing and Inspection.

Is the in-car temperature sensor OK?

YES -

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

NO -

Replace the in-car temperature sensor Service and Repair.

7. Disconnect climate control unit connectors A (28P) and B (12P).

8. Check for continuity between climate control unit connector A (28P) terminal No. 26 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 A (28P) terminal No. 26 and climate control unit connector B (12P) terminal No. 10.





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.