Heated Oxygen Sensor (HO2S)

On single oxygen sensor equipped vehicles, sensor is located in exhaust system in front of catalytic converter. On dual oxygen sensor models, a second sensor is installed between converter and muffler.

Oxygen sensor monitors oxygen content of exhaust gases and produces voltage depending on concentration of oxygen. Voltage produced by sensor ranges from zero volts (lean) to about one volt (rich). ECM monitors sensor signal to control fuel delivery time.