Description and Operation: Description
Heated Oxygen Sensor (HO2S), consisting of zirconium and alumina, is installed on both upstream and downstream of the Manifold Catalytic Converter (MCC) to detect the air/fuel ratio and send it to the ECM.
In order that this sensor operates properly, the temperature of the sensor tip must be higher than 370°C (698°F). For this reason, a heater controlled by the ECM duty signal, is built into the sensor.
When the exhaust gas temperature is lower than the specified value, the heater warms the sensor tip.