Technical Description (Comment)

Current trouble 

• The heater controller assembly (A/C-ECU), the fin thermo sensor, or connector(s) or wiring between the two may be defective.

Past trouble 

• If DTC B1031 or B1032 is set as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the heater controller assembly (A/C-ECU) and the fin thermo sensor. If the connectors and wiring are normal, and obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do not replace the ECU.