How to Identify a California Compliant Catalytic Converter

If you live in California, replacing your vehicle’s catalytic converter isn’t as simple as picking the cheapest one online. Due to strict emissions regulations enforced by the California Air Resources Board (CARB), it’s crucial to ensure you're buying a California catalytic converter that meets specific standards. 

This guide explains how to identify a compliant converter, what markings to look for, and how to avoid costly mistakes when buying a replacement.

1. Look for CARB Certification Markings

The most reliable way to verify whether a catalytic converter is legal in California is to check for a CARB Executive Order (EO) number. This number proves the unit meets California’s emission standards. A valid EO number will appear as a series of letters and digits etched directly into the catalytic converter body.

What to look for:

• CARB EO Number (e.g., D-193-140)
• Part Number
• Date of Manufacture
• Direction of Flow Arrow

Each of these markings must be permanently affixed and legible. If any information is missing, especially the EO number, the converter may not be California compliant, except in the case of an OEM (Original Equipment Manufacturer), which does not have or require EO numbers. 

2. Where to Find These Markings

Most catalytic converters display this information engraved or etched directly into the housing. It can be located on the top, bottom or on one of the sides in a conspicuous location.

Visual tip: Look for an etching with the prefix EO-D followed by a number series (e.g. EO-D-193-57). It may be located near the heat shield or inlet/outlet pipes.

If you're unsure, ask the seller to provide an EO number for your test group and specific vehicle before purchase. Reputable manufacturers, such as MagnaFlow, often feature this information clearly in product listings for their MagnaFlow catalytic converter models.

3. Tips for Verifying Compliance When Purchasing

Not all catalytic converters labeled as “EPA compliant” are acceptable in California. While an EPA compliant catalytic converter might be legal in other states, California requires a CARB-compliant version.

Here’s how to make sure you’re buying the right one:

• Check the CARB EO Number: Visit the CARB Aftermarket Parts Database and enter the EO number to verify its validity.
• Use California-Specific Retail Filters: Many websites that sell catalytic converters online allow you to filter results by state. Always select “California” or “CARB Compliant” to narrow down your search.
• Verify Fitment: A compliant converter must also match your vehicle’s make, model, engine size, year, and test group number.

4. Avoiding Non-Compliant or Counterfeit Converters

Unfortunately, counterfeit and non-compliant converters are common, especially when shopping online. Using a non-compliant catalytic converter in California is not only illegal but can also result in fines or a failed smog check.

How to avoid scams:

• Avoid Suspiciously Low Prices: If the price seems too good to be true, it probably is. CARB-compliant converters are more expensive due to rigorous testing.
• Buy from Trusted Brands and Retailers: Stick with reputable brands like MagnaFlow and buy from verified retailers or authorized dealers.
• Don’t Trust Verbal Claims: Always insist on seeing the CARB EO number and verifying it on the CARB website before buying.

Why It Matters

California’s emissions regulations are among the strictest in the country. Installing a non-compliant converter not only harms the environment but also creates legal and mechanical headaches for you. Smog tests can detect non-compliant converters, and failing a test may prevent you from registering your vehicle.

Whether you’re buying in-store or browsing catalytic converters online, taking a few minutes to verify compliance can save you hundreds of dollars and ensure your vehicle stays road-legal.

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Want to make sure you're buying the right converter? Visit HottExhaust.com and purchase the correct California catalytic converter. We have multiple models and types to fit your vehicle perfectly. Plus, you’ll get FAST and FREE shipping directly to your doorstep. Your vehicle, wallet, and the environment will thank you.

Contact us today.