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

3. Do the self-diagnostic with the HDS Initial Inspection and Diagnostic Overview or 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.


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

6. Remove the in-car temperature sensor Service and Repair and test it. In-Car Temperature Sensor Test

Is the in-car temperature sensor OK?
YES - Go to step 7.

NO - Replace the in-car temperature sensor.


7. Disconnect climate control unit connector B (16P).

8. Check for continuity between body ground and the climate control unit connector B (16P) No. 14 terminal.

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 the climate control unit connector B (16P) No. 4 and No. 14 terminals.

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.