Heated Oxygen Sensor (HO2S)
The heated oxygen sensors are mounted in the exhaust manifold and pipe. See Fig 1 . HO2S sensor uses a built-in heating circuit. The heating circuit is used to bring the HO2S sensor up to operating temperature, enabling faster conversion to closed-loop operation.
HO2S monitors oxygen content of exhaust gases. When HO2S is at operating temperature, a voltage signal is produced, which varies according to oxygen content of exhaust gases. Signal is transmitted to the PCM and is translated into a rich or lean mixture signal.