U0664Lost Communication With Rear HVAC Air Cutoff Actuator
- Generic OBD-II code · Network
- How the car detects it
- Some climate units carry a door that opens or shuts the whole air supply to the rear seats, so the system can send everything forward when nobody sits in the back or when the front needs full airflow. Hanon's US 11,305,608 places such an on-off door on the rear cold-air passage, and Denso's US 2020/0189351 moves its rear airflow door to feed or close the rear vent and heat outlets. U0664 means the climate master has lost contact with the actuator of this door. No maker documents the code in public. The impact depends on where the door stopped: closed, the rear gets no conditioned air at all; open, the rear keeps blowing even when switched off and the front loses some airflow, most noticeable during maximum cooling or defrost.
- What you may notice
- No air at the rear outlets
- Rear outlets keep blowing although rear climate is off
- Reduced airflow at the front during maximum cooling or defrost
- Likely causes
- LikelyRear cutoff door actuator failed
- PossibleActuator plug at the rear outlet of the HVAC case not seated
- RareLIN or supply wire to the cutoff actuator damaged
- Repair
- Hard · Usually a job for a workshop.Typical cost: €60 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.