Catalyst Monitor Diagnostic Tests

The emissions control system used on this vehicle has a 3-way catalytic (TWC) converter in order to reduce exhaust emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalyst material inside of the converter promotes a chemical reaction in order to combine oxygen with the HC and CO, converting them to water vapor (H2O) and harmless carbon dioxide (CO2). The NOx is converted to nitrogen (N) by the converter.

The control module has the ability to monitor the efficiency of the catalytic converter through the use of a heated oxygen sensor (HO2S) mounted in the engine exhaust gas stream after the catalytic converter (post-catalyst).