Heated Oxygen (HO2S) Sensor

Heated Oxygen Sensor-1 (HO2S-1)
The oxygen sensor is installed on the exhaust manifold to detect the concentration of oxygen in the exhaust gases. The oxygen sensor heater promotes activation of the oxygen sensor.





Heated Oxygen Sensor-2 (HO2S-2)
The oxygen sensor is installed on the rear side of TWC to detect the concentration of oxygen in the exhaust gases just like HO2S-1.
ECM judges deterioration of TWO by comparing waveforms of the output voltage from HO2S-1 and HO2S-2.