Description And Operation: Description
Heated Oxygen Sensor (HO2S), consisting of zirconium and alumina, is installed on both upstream and downstream of the Catalytic Converter to detect the air/fuel ratio and send it to the ECM.
The sensor must be heated in order to operate properly. To keep it heated, the sensor has a heater which is controlled by the ECM via a duty cycle signal. When the exhaust gas temperature is lower than the specified value, the heater warms up the sensor tip.