Heated Oxygen Sensor

Heated Oxygen Sensor (HO2S) detects oxygen content in exhaust gas and sends this information to PCM. PCM uses input signals from front HO2S to control air-fuel mixture by varying duration of fuel injection. PCM compares signals from rear HO2S to signals from front HO2S to monitor catalytic converter performance. HO2S heater speeds heating of HO2S which speeds up entry into closed loop operation. HO2S heater also stabilizes sensor temperature regardless of exhaust gas temperature to allow for more accurate exhaust oxygen content readings.