Oxygen Sensor: Description and Operation

This vehicle is equipped with four heated oxygen sensors (HO2S), two per engine bank. Each bank has a feedback (front) oxygen sensor and an OBD monitor (rear) oxygen sensor.

The two, left front and right front, feedback HO2S sensors are used for closed loop mixture control with the ECM.

The two, left rear and right rear, OBD monitor sensors are used to measure the operating efficiency of the mixture ratio feedback control and catalytic converter systems. The two rear OBD monitor sensors do not directly affect engine operation but act as system operation monitors.