Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1): Notes
The Heated Oxygen Sensors (HO2S) detect the oxygen content in the exhaust gas and signal the ECM/PCM. In operation, the ECM/PCM receives the signals from the sensor and varies the duration during which fuel is injected. To stabilize the sensor's output, the sensor has an internal heater. The Primary HO2S (Sensor 1) is installed in the exhaust manifold.