Due to a Federally mandated extended warranty covering emissions-related components like the catalytic converter, it is advisable to consult a dealer service department before incurring replacement costs. The catalytic converter serves as an emission control device in the exhaust system, designed to reduce pollutants in the exhaust gas stream, with two types available: the conventional oxidation catalyst, which decreases hydrocarbon and carbon monoxide levels, and the three-way catalyst, which also reduces oxides of nitrogen. Testing equipment for catalytic converters is costly and sophisticated; if a malfunction is suspected, it is best to seek diagnosis and repair from a dealer or authorized emissions inspection facility. During any servicing that raises the vehicle, it is important to inspect the converter for leaks, corrosion, dents, and other damage, including checking the welds and flange bolts connecting the converter to the exhaust system, as any damage found necessitates replacement. Although catalytic converters are durable, they can become plugged, and a vacuum gauge can be used to check for restrictions by monitoring intake vacuum at around 2000 RPM; a quick drop in gauge reading indicates no restriction, while a reading that hovers or shows significant elevation suggests a blockage in the exhaust system or converter. Since the converter is welded to the exhaust system, replacing it requires the removal of the exhaust pipe assembly, which should be handled by a dealer service department or muffler shop.