The pollutant detector for the automatic recirculated air control system (AUC) is installed on the air inlet of the auxiliary fan. The evaluation electronics necessary for this sensor is integrated in the air conditioning control unit.
The AUC function is activated by pressing the recirculated air/AUC button. The function light above the AUC symbol indicates the function is in standby mode.
When starting the vehicle, fresh air is always supplied for 90 seconds due to the AUC sensor heating-up time.
Generally in recirculated air mode, the relative humidity in the interior of the vehicle can increase due to the lack of fresh air. This results in condensation forming on the window. For this reason, the recirculated air status is limited in AUC mode dependent on heating or air conditioning operation.
Once these times have elapsed, the air supply switches automatically back to outside air (fresh air flap open) for 1 minute. The AUC function is active once again after the minute has elapsed.