Catalytic Converter
WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
A Three-Way Catalytic (TWC) converter is used to reduce exhaust emissions. This type of converter can reduce Hydrocarbons (HC), Carbon Monoxide (CO) and Oxides Of Nitrogen (NOx).