The exhaust system is vital for a couple of reasons. First, it safely removes the toxic gases created by the engine’s combustion. Secondly, it monitors the gases produced by the engine via sensors that provide feedback information to the engine control module for proper fuel delivery. If the system leaks due to a gasket failure, rusted muffler, or damage due to an accident, it needs to be repaired immediately. The leaking gases can enter the passenger compartment and put the opponents to sleep, and they may not even smell the gases. As for the engine, the leak will give the sensors a false reading, and the engine controller will not deliver the proper fuel mix. Fuel mileage will decrease, and the added carbon will damage other systems.

The catalytic converter has been on US-built cars and light trucks since the mid-1970s. The purpose of the catalytic converter is to reduce the exhaust emissions of the internal combustion engine. The internal construction of the converter consists of a ceramic beeswax-style honeycomb. This honeycomb is coated with a platinum-iridium catalyst. The exhaust system gases cause the catalytic converter to reach extremely high temperatures. As the carbon monoxide enters the chamber of the catalytic converter, it is oxidized. In 1996, automobile manufacturers in the U.S. were required to add a sensor known as the downstream O2 sensor. The purpose of this sensor is to monitor the exhaust gas and ensure it is oxidized to an acceptable level.