When it comes to vehicle emissions in California, few components are more critical than the catalytic converter—and few regulations more important than the CARB Executive Orders (EOs) that govern them. Whether you're replacing a converter or ensuring compliance with California emissions laws, understanding CARB EOs is essential.

This guide takes a deep dive into what CARB Executive Orders are, how they affect your vehicle’s emissions equipment, and where to find the right information to ensure compliance with California emissions catalytic converter standards.

What Are CARB Executive Orders?

CARB stands for the California Air Resources Board, a state agency that sets and enforces emission standards to help reduce air pollution. One of CARB’s most important tools in regulating vehicle emissions is the Executive Order (EO). When a manufacturer wants to sell an aftermarket catalytic converter in California, it must undergo testing and receive approval from CARB in the form of an Executive Order number.

This EO number certifies that the converter meets California’s stringent emission standards and is legal for use in the state. Without a valid EO, a catalytic converter cannot be installed on a California-registered vehicle—even if it works perfectly in other states, with the exception of  OEM parts.

Why CARB EOs Matter

CARB EOs are more than just regulatory paperwork. They directly impact:

• Vehicle registration and inspections: If your catalytic converter isn’t CARB-approved, your vehicle may fail emissions testing, and you may not be able to register it in California.
• Legal compliance: Using a non-CARB-approved converter on a California vehicle violates California emissions laws, and fines can be steep.
• Environmental protection: These rules are in place to ensure vehicles meet California's strict environmental standards, helping reduce smog and greenhouse gas emissions.

In short, understanding and using the right CARB EO is essential for any vehicle owner or technician working on emissions systems in California.

How to Find and Interpret the EO Number

Every CARB-approved catalytic converter will come with a metal label or plate that includes its EO number. This number is your proof that the part is legal in California. Here’s how to read and understand it:

EO Number Format

A typical CARB EO number looks something like this: D-193-140.

• The "D" indicates the device is emissions-related.
• The next number (e.g., 193) refers to the manufacturer’s assigned ID number.
• The final number (e.g., 140) represents the specific Executive Order for that part or product line.

You can use this number to verify the part’s legality on the CARB website or other trusted databases.

Matching EOs to Vehicle Applications

It’s not enough for a catalytic converter to just have a CARB EO—it must be approved for your specific vehicle. The EO documentation will list:

• Make, model, and engine size compatibility
• Installation requirements (e.g., position on the vehicle)
• Emission certification type (e.g., LEV, ULEV, SULEV) or Test Group number  (e.g.6HNXV02.4CMC)

Always double-check that the EO number matches your car’s specs before purchasing or installing a converter. Using the wrong EO-approved part can still result in non-compliance.

Implications of Different EO Numbers

Not all EO numbers are the same. Some are issued for specific converter designs, while others may be updated over time. Here are a few things to keep in mind:

• Older EO numbers may not be valid for newer vehicles with updated emission standards.
• Multiple EOs might exist for similar converters, but only one may be valid for your exact application.
• If a converter loses CARB approval, its EO may be revoked, meaning it’s no longer legal for sale or use in California.

Keeping up with changes in EO listings is crucial, especially for repair shops and parts suppliers.

Where to Look Up CARB EO Information

There are several trusted resources for looking up EO numbers and verifying legality:

1. CARB Aftermarket Parts Database

CARB maintains an official searchable database of EO numbers at: https://ww2.arb.ca.gov 

Here, you can search by EO number, part number, or manufacturer to find detailed information, including approved vehicle applications and installation instructions.

2. Manufacturer Websites

Many reputable converter manufacturers, such as MagnaFlow or Walker, provide EO lookup tools on their websites. These databases are often more user-friendly and include product images and cross-reference tools.

3. Smog Check Facilities

Licensed smog check stations often have access to CARB EO documentation and can help you verify whether a converter is compliant with California emissions laws.

Staying Compliant with California Emissions Laws

California’s vehicle emissions rules are among the strictest in the world. To stay compliant:

• Always install converters that are CARB-approved for your vehicle.
• Keep the EO sticker or documentation handy for inspections.
• Avoid purchasing converters from non-certified sources, especially online sellers who may not follow California regulations.
• If you’re unsure, consult a certified technician or smog check professional.

By staying informed about CARB Executive Orders, you ensure that your vehicle meets California emissions catalytic converter requirements while helping protect air quality across the state.

Choose HottExhaust & Experience the Difference 

Need help finding the right catalytic converter for your vehicle? Look no further than HottExhaust, your trusted online store for catalytic converters in the USA. We pride ourselves on offering fast shipping directly to your door and exclusive discounts to ensure you get the best value. Plus, we carry MagnaFlow products, renowned for their superior quality and performance, ensuring your vehicle meets all necessary emissions standards.

For your next catalytic converter purchase, choose HottExhaust and experience the difference that quality products, excellent service, and unbeatable convenience can make. 

Shop with us today!