Oxygen Sensor: Description and Operation

The oxygen sensor, mounted in the exhaust manifold, is used to provide more precise control of air/fuel mixtures. This system operates by measuring oxygen content in exhaust gasses, as the amount of oxygen remaining in the exhaust gases is directly proportional to the air/fuel ratio of mixtures entering the engine.

The difference in the amount of oxygen contacting the inner and outer surfaces of the oxygen sensor creates a pressure differential which results in a voltage signal being generated. The amount of voltage produced is determined by the air/fuel mixture, A high voltage (0.7 - 1.0 volt) indicates a rich mixture, and a low (0 - 0.3 volts) voltage indicates a lean mixture.