Oxygen Sensor: Description and Operation

Heated Oxygen Sensor

Fig. 57 O2 Sensor:

The heated oxygen sensor, located in the exhaust tube, monitors oxygen level in the exhaust gas.

The sensor is made of ceramic titania, the electric resistance of which drastically changes at the ideal air/fuel ratio.

O2 Sensor Operation:

The ECM suppiles the sensor with approximately 1V and then measure the output voltage depending on it's resistance. In order to activate the sensor element, it is equipped with a heater.