The three way catalytic converter (TWC) converts hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO2), nitrogen (N2), and water vapor.
The TWC is attached directly under the cylinder head that is integrated into the exhaust manifold.

The warm up three way catalytic converter (WU-TWC) and the under-floor three way catalytic converter (Under-floor TWC) convert hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO2), nitrogen (N2), and water vapor. The WU-TWC is attached directly under the each cylinder head that is integrated into the exhaust manifold.