The catalytic converter is a key part of the emission control system. It convert harmful pollutants in the exhaust gas into harmless gases. It is a stainless steel container, mounted after the exhaust manifold, that holds a honeycomb-like structure called a catalyst. This catalyst causes a chemical change within the exhaust gas that decreases the amount of HC, CO, and NO in the exhaust gas.
While most catalytic converters are pretty reliable, they can still be damaged. If engine maintenance is neglected, it could cause the converter to become damaged, which would result in the in converter having to be replaced.
The catalytic converter is covered under the federal or state emissions warranty found within the manufacturer factory warranty. If the manufacturer bumper-to-bumper factory warranty expires after the emissions warranty, then the converter will be covered until the factory warranty expires, as long as it fails due to a manufacturer defect or workmanship.