Heated Oxygen Sensor (HO2S)

All vehicles are equipped with dual oxygen sensors. The first sensor is located in the exhaust manifold, and the second sensor is installed at the rear of the catalytic converter. HO2S determines oxygen content of exhaust gases and produces a voltage depending on concentration of oxygen. Output voltage of the sensor ranges from zero volts (lean) to about one volt (rich). The ECM monitors this sensor signal to control fuel delivery time.