Oxygen Sensor (O2S) 1

The main function of the Oxygen Sensor (O2S) is to provide the control module with exhaust stream information to allow proper fueling and maintain emissions. After it reaches operating temperature, the sensor will generate a voltage, inversely proportional to the amount of oxygen present in the exhaust stream. The control module uses the signal voltage from O2S 1 to adjust fuel injector pulse width to maintain a 14.7:1 air/fuel ratio. The O2S 1 is also used on California vehicles to compare pre catalyst and post catalyst activity and determine catalyst efficiency from these calculations.