Automatic Recirculated Air Control (AUC)

AUTOMATIC RECIRCULATED AIR CONTROL (AUC)







AUC functions the same as on the E38. The AUC sensor is positioned on the driver's side of the radiator shroud next to the radiator inlet hose. This location provides easy service access as well as an ideal position to monitor the levels of oxidizable gasses in the incoming air stream flowing through the radiator.

The sensor is heated to its operating temperature by the IHKA module. If the level of gasses exceeds a set threshold value, the recirc flaps are automatically opened.

When the level of noxious gasses drops, the fresh air flaps will again open. AUC is subject to time limits to prevent glass fogging:

- 3 minute cycling when heating
- 12 minute cycling when cooling