Heated/Exhaust Gas Oxygen Sensor

Located in exhaust manifold, the heated/exhaust gas oxygen sensor measures amount of unburned oxygen in exhaust. If oxygen is low (rich mixture), higher voltage will be generated by sensor. If oxygen is high (lean mixture), lower voltage will be generated. Voltage signal from oxygen sensor is sent to ECU which controls fuel mixture through the differential pressure regulator. The heated portion is used to rapidly warm the oxygen sensor for more effective emission controls.