Oxygen Sensor: Description and Operation

Heated Oxygen Sensor (HO2S)






The EEC-IV systems use only one Heated Oxygen Sensor (HO2S) for engine control. The EEC-V system uses two HO2S's. One for engine control and the other for catalyst monitoring.

The heated oxygen sensor reacts with the oxygen in the exhaust gases and generate a voltage based on this reaction. A low voltage indicates too much oxygen or a lean condition. A high voltage indicates not enough oxygen or a rich condition. The heated oxygen sensors are located in the exhaust pipes between the exhaust manifolds and the catalyst can.