C 2500 Suburban 2WD V8-454 7.4L VIN J SFI (1998)
Heated Oxygen Sensor: Description and Operation
Fuel Control HO2S
Heated Oxygen Sensor (HO2S) Cutaway
OPERATION
In order to control the emissions of Hydrocarbons (HC), 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 VCM has the ability to monitor this process by using the Bank 1 Sensor 2 and the Bank 1 Sensor 3 heated oxygen sensors. The Bank 1 Sensor 2
sensor produces an output signal which indicates the amount of oxygen present in the exhaust gas entering the three-way catalytic converter. The Bank
1 Sensor 3 sensor produces an output signal which indicates the oxygen storage capacity of the catalyst; this in turn indicates the ability of the catalyst
