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CA Emissions Vehicle in an EPA State – Which Converter Should I Get?

EPA vs CARB Catalytic Converters

Most states require an aftermarket catalytic converter that meets federal Environmental Protection Agency (EPA) policy. However, some states have enacted regulations that require the use of a CARB-compliant aftermarket catalytic converter to meet the standards of the California Air Resource Board (CARB). Currently a handful of states – California, Colorado, Maine and New York – have enacted regulations that require CARB-compliant aftermarket catalytic converters. If you are in any other state, you should use aftermarket catalytic converters that comply with EPA policy.


Selecting the Right Catalytic Converter

Key for a successful repair, determining the correct converter is usually a straightforward process of looking up your vehicle information in the parts catalog. However, questions can arise when the state the owner lives in and the state that the vehicle originated in are different.

CARB-Certified Vehicles in EPA States

If you have a vehicle that is CARB, California, ARB or 50 state emissions certified but you live in a state that follows EPA emissions policy for aftermarket converters, you may wonder if you should purchase a CARB-compliant converter or an EPA-compliant converter.

For states that don’t require CARB-compliant aftermarket converters to be installed, you can follow EPA policy and install an EPA-compliant aftermarket converter.

Walker® aftermarket replacement converters are designed to meet the unique emissions performance needs of each vehicle based on emissions performance requirements & vehicle fitment. If a Walker EPA-compliant converter is cataloged matching the vehicle and emissions certification, there should not be an issue with compatibility - no need to upgrade to a CARB-compliant converter because of emissions performance concerns. Walker’s online catalog takes the guesswork out of selecting the right replacement part with our catalytic converter lookup by state including dropdown selections and notes based on vehicle emissions certification and fitment.


In some instances, fitment will be important to ensure you order the correct replacement EPA converter for California emissions certified vehicles. There may be a difference in physical fitment or routing on the vehicle between California emissions and Federal emissions certified models.

If there are fitment differences between the California & Federal emissions certified models of the same vehicle, Walker will introduce a separate EPA-compliant converter for fitment compatibility specific to the California emissions certified model to account for the fitment differences. This can be common on super ultra-low emission vehicle (SULEV) models.

Learn more about premium catalytic convertersfind the right car part, or find a local repair shop today.


The content in this article is for informational purposes only. You should consult with a certified technician or mechanic if you have questions relating to any of the topics covered herein. Tenneco will not be liable for any loss or damage caused by your reliance on any content.

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