Oxygen (O2) Sensor

The O2 sensor produces a small electrical voltage (.1-.9 volt) when exposed to oxygen in exhaust gasflow. O2 sensor is electrically heated for faster switching. Heating element is powered through Auto Shutdown (ASD) relay.

O2 sensor acts like a rich/lean (air/fuel ratio) switch by monitoring oxygen content in exhaust gas. This information is used by PCM to adjust air/fuel ratio.

O2 sensor produces low voltage when oxygen content in exhaust gas is high. When oxygen content in exhaust gas is low, O2 sensor produces a higher voltage.