Q: Will I Void My Warranty if I Change My Car's Exhaust System?

As a general rule of vehicle warranty, you cannot modify your vehicle’s exhaust system if it involves any smog-related component, such as catalytic converters, while your vehicle is still under an emissions warranty. Emissions warranties are valid for a longer period of time and for a higher amount of mileage than regular vehicle warranties. Replacing emission control devices with aftermarket upgrades, not service replacements, would void your manufacturer warranty and the cost of repairs would be your responsibility if something were to go wrong.

Some exhaust system components like headers and high-flow catalytic converters can be upgraded if the components have been tested, certified, and approved by the state for use as a replacement emissions control component. Keep in mind that doing so will invalidate the manufacturer’s warranty on those components. It you install these components after the emission control warranty for your vehicle has expired, then you don’t have to worry about voiding the warranty or not.

There are upgrades that you can do to your exhaust system that don’t interfere with emissions warranties. Generally, these upgrades to your exhaust system are referred to as "cat-back" systems because they replace the exhaust system from the back of the catalytic converter to the rear of the vehicle. The catalytic converter is not replaced in this situation.