Technical Description (Comment)

Current trouble 

• The A/C-ECU, the A/C control panel, or connector (s) or wiring between the two may be defective.

Past trouble 

• If DTC B1000 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the A/C-ECU and the A/C control panel. 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.