Oxygen Sensor: Description and Operation

Oxygen Sensor Construction and Operation:

One oxygen (O2) sensor is mounted to the each exhaust manifold with the sensor end extending into the exhaust stream. The sensors use zirconia and platinum to compare exhaust oxygen content with that of the outside air. When heated by the exhaust, the sensors supply a low voltage signal (0 - 1 volt) to ECU pins C10 and C12 based upon this oxygen differential. When the engine is running rich, the oxygen differential is relatively high, so signal voltage increases. When a lean condition occurs the difference in oxygen content is much lower causing a lower voltage signal to be produced. The ECU uses the O2 signals to correct fuel mixture by changing injector duration as required.