LSS V6-3.8L VIN K (1997)
Oxygen Sensor: Description and Operation
Catalyst Monitor Oxygen Sensors
To control emissions of Hydrocarbons (HO), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), a three-way catalytic converter is used. The
catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas, converting them into
harmless water vapor and carbon dioxide. The catalyst also reduces NOx, converting it to nitrogen. The PCM has the ability to monitor this
process using the HO2S 1 and the HO2S 2 heated oxygen sensors.
The HO2S 1 sensor produces an output signal which indicates the amount of oxygen present in the exhaust gas entering the three-way catalytic
converter.
The HO2S 2 sensor produces an output signal which indicates the oxygen storage capacity of the catalyst; this in turn indicates the catalyst's ability
to convert exhaust gases efficiently. If the catalyst is operating efficiently, the HO2S 1 signal will be far more active than that produced by the
HO2S 2 sensor. The catalyst monitor sensors operate the same as the fuel control sensors.
