October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

Heated Oxygen Sensor

At operating temperature, Heated Oxygen Sensor (HO2S) monitors oxygen content of exhaust gases. A heating circuit is used to warm HO2S to operating temperature, enabling faster conversion of feedback system to closed loop operation.

HO2S produces low voltage (less than .4 volt) to indicate lean mixture (high amount of oxygen) and a high voltage (more than .6 volt) to indicate rich mixture (low amount of oxygen). This voltage signal is transmitted to PCM.