DTC Troubleshooting: B1227 (C)

DTC indicator C or DTC B1227:  An Open in the Outside Air 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 C or B1227 indicated?


YES - Go to 5.


NO - Intermittent failure, check for loose wires or poor connections on the outside air temperature sensor circuit.n


5.Remove the outside air temperature sensor and test it.

Does the outside air temperature sensor test OK?


YES - Go to 6.


NO - Replace the  outside air temperature sensor.n


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

7.Check for continuity between the No. 12 terminal of climate control unit connector A (22P) and the No. 1 terminal of the outside air temperature sensor 2P connector.

Is there continuity?


YES - Go to 8.


NO - Repair open in the wire between the climate control unit and the outside air temperature sensor.n

8.Check for continuity between the No. 15 terminal of climate control unit connector A (22P) and the No. 2 terminal of the outside air temperature sensor 2P connector.

Is there continuity?


YES - Go to 9.


NO - Repair open in the wire between the climate control unit and the outside air temperature sensor.n


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

Is the communication OK?


YES - Check for loose wires or poor connections at climate control unit connector A (22P) and at the outside air temperature sensor 2P connector. If the connections are good, 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 - Check for loose wires or poor connections at climate control unit connector A (22P) and at the outside air temperature sensor 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.n