DTC Troubleshooting: B1226 (B)

DTC indicator B or DTC B1226:  A Short in the In-car Temperature Sensor Circuit


1.Clear the DTC.

2.Turn the ignition switch OFF, and then ON.

3.Operate the climate control system is several modes.

4.Check the DTCs.

Is DTC B or B1224 indicated?


YES - Go to 5.


NO - Intermittent failure.n


5.Remove the in-car temperature sensor.

6.Test the in-car temperature sensor.

Is the resistance within the specifications shown on the graph?


YES - Go to 7.


NO - Replace the  in-car temperature sensor.n


7.Disconnect climate control unit connector A (22P).

8.Check for continuity between the No. 11 terminal of climate control unit connector A (22P) and body ground.

Is there continuity?


YES - Repair short to body ground in the wire between the climate control unit and the in-car temperature sensor.n


NO - Go to 9.


9.Perform the A/C communication in the Self-Diagnostic Function to obtain the IS-BUS communication verification status.

Is the communication OK?


YES - Substitute a known-good climate control unit and printed circuit board, and recheck. If the symptom/indication goes away, replace the original climate control unit and printed circuit board.n


NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.n