DTC Troubleshooting: B1227 (C and AUTO)

  1. Check for continuity between heater control unit connector B (12P) No. 10 terminal and the outside air temperature sensor 2P connector No. 2 terminal.
Is there continuity?
YES -
Check for loose wires or poor connections at heater control unit connectors A (28P), B (12P), and at the outside air temperature sensor 2P connector. If the connections are good, substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■
NO -
Repair open in the wire between the heater control unit and the outside air temperature sensor.■