Catalyst Monitor Heated Oxygen Sensor

In order to control emissions of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), the system uses a three-way catalytic converter. 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 Control Module has the ability to monitor this process using the Bank 1 Sensor 2, Bank 2 Sensor 2 heated oxygen sensors.

The Bank 1 Sensor 1 and the Bank 2 Sensor 1 sensors produce and output signal which indicates the amount of oxygen present in the exhaust gas entering the three-way catalytic converter. The Bank 1 Sensor 2 and the Bank 2 Sensor 2 sensors produce an output signal which indicate the oxygen storage capacity of the catalyst, this in turn indicates the catalyst's ability to covert exhaust gasses efficiently. If the catalyst is operating efficiently, the Bank 1 Sensor 1 and Bank 2 Sensor 1 signals will be far more active than those produced by the Bank 1 Sensor 2 and Bank 2 Sensor 2 sensors. In addition to catalyst monitoring, the Bank 1 Sensor 2 and Bank 2 Sensor 2 heated oxygen sensors have a limited role in controlling fuel delivery. If the Bank 1 Sensor 2 and/or Bank 2 Sensor 2 signals indicate a high or low oxygen content for an extended period of time while in a closed loop, the Control Module adjusts the fuel delivery slightly in order to compensate.