Third Oxygen Sensor

Third Heated Oxygen Sensor (Third HO2S) ('02-03 M/T models)
The third HO2S detects the oxygen content in the exhaust gas downstream of the NOX Adsorptive Three Way Catalytic Converter (NOX Adsorptive TWC) and sends signals to the ECM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The third HO2S is installed behind the NOX Adsorptive TWC.