Automatic Recirculated Air

AUTOMATIC RECIRCULATED AIR (AUC if equipped)







The IHKA control module uses data from the AUC sensor to determine whether recirculating air mode is necessary. The AUC sensor samples ambient air that has entered the engine compartment. The sensor contains a gas sensor, which measures the level of oxidizable gasses in the air. These include hydrocarbons, NOx, SOx, and CO.

The IHKA control module monitors the change in the voltage signal as these gasses influence the sensor. The second circuit shown is a heating circuit which enhances the sensor's reaction time. When starting the vehicle, fresh air is always supplied for 90 seconds due to the AUC sensor heat-up time.