The sensor consists of a nitrogen and oxygen probe and a  circuit system. The sensor can detect exhaust gas and translate into digital information and send to the after treatment  system (SCR and other systems), also access to the OBD  system. It is an electrochemical sensor which detects the NOX  and O₂  concentration in gas. The detected data is sent and the  instructions from the upper system are received via CAN,  which realizes the communication of the sensor. 

It is mainly used in after treatment systems of fuel and gas  vehicle engines, such as SCR system and EGR system.