Operation CHARM: Car repair manuals for everyone.

C and Auto




DTC Troubleshooting: B1227 or Indicator C and AUTO

DTC B1227 or DTC indicator C and AUTO:An Open in the Outside Air 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 B1227 or C and AUTO indicated?
YES - Go to step 5.

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


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

6. Remove the outside air temperature sensor Service and Repair and test it. Outside Air Temperature Sensor Test

Is the outside air temperature sensor OK?
YES - Go to step 7.

NO - Replace the outside air temperature sensor.


7. Disconnect climate control unit connector A (24P).

8. Check for continuity between the climate control unit connector A (24P) No. 14 terminal and the outside air temperature sensor 2P connector No. 1 terminal.

Is there continuity?
YES - Go to step 9.

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






9. Check for continuity between the climate control unit connector A (24P) No. 18 terminal and the outside air temperature sensor 2P connector No. 2 terminal.

Is there continuity?
YES - Check for loose wires or poor connections at the climate control unit connector A (24P) 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.

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