Heated Oxygen Sensor (HO2S)
WARNING: This page is about a different car, the 1994 Mercury Sable, 1994 Mercury Cougar, 1994 Lincoln Continental, 1994 Ford Thunderbird, and 1994 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
HO2S monitors oxygen content of exhaust gases. This electrically heated O2 sensor is mounted in the exhaust manifold or pipe. 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.
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. All V6 and V8 engines are equipped with 2 sensors, one for each exhaust bank.