Failed smog? Find a CARB-legal catalytic converter for your exact car.
Not every catalytic converter is street-legal in California. Type your Engine Family Number and get an instant, verified answer, plus the certified parts that actually fit.
You went to get your car smogged, and it failed, or the dashboard is lit up with a P0420 code. The shop says you need a new catalytic converter. So you search online, and half the converters are cheaper… but buried in the fine print are five words that matter more than the price: "Not legal for sale in California."
If you live in California, Colorado, New York, or Maine, buying the wrong converter means it won't pass smog, can't be legally installed, and won't clear your check-engine light. You'd be back to square one, out the money and the labor. This guide explains exactly what makes a converter street-legal in these states, and how to confirm a legal one exists for your specific vehicle before you spend a dollar.
The 30-second version
In CARB states, a replacement converter must carry a CARB Executive Order (EO) number that covers your year, make, model, and engine. Our checker confirms that instantly from your Engine Family Number, then shows you the certified parts that fit.
The basics
What is a CARB-certified catalytic converter?
CARB stands for the California Air Resources Board, the agency that sets tailpipe-emissions rules stricter than the federal EPA. A CARB-certified (or "CARB-compliant") catalytic converter is one that CARB has independently tested and approved as a legal aftermarket replacement, issuing it an official Executive Order (EO) number for a defined list of vehicles.
That EO number is the whole game. It's proof the converter meets California's emissions standard for your car. It is the document a smog technician, a parts counter, and the DMV all recognize. A converter without an EO number is a "49-state" or "federal" converter: fine in most of the country, but illegal to sell or install in CARB states.
CARB-certified vs. 49-state converters
| CARB-certified | 49-state (federal) | |
|---|---|---|
| Legal in CA / CO / NY / ME | Yes | No |
| Carries an EO number | Yes | No |
| Passes California smog | Yes | No |
| Clears the emissions readiness monitor | Designed to | Often won't |
| Legal in the other 46 states | Yes | Yes |
A CARB-certified converter is legal everywhere. A 49-state converter is the one that gets people in trouble.
Why it matters
Why you can't just buy any catalytic converter in California
It is illegal to advertise, sell, offer for sale, or install a non-CARB converter on a pollution-controlled vehicle in these states. This isn't a technicality. Smog stations physically inspect the converter and check its EO number. No valid EO for your vehicle, no pass.
The expensive mistake
A federal converter can be hundreds of dollars cheaper, which is exactly why people buy one by accident. Then it fails smog, can't be returned once installed, and the whole job gets paid for twice. Confirming the EO up front is the entire point of the checker below.
The checker
How to check if a converter is legal for your car
No part numbers, no guesswork, no calling the dealer. Our checker takes one input, your Engine Family Number, and instantly tells you whether a CARB-legal converter exists for your exact vehicle, along with the Executive Order that covers it.
Find your Engine Family Number
It's printed on the emissions label under your hood, a short code like MHNXV02.4G3R. (Full instructions in the next section.)
Type it into the checker
Enter the code and hit Check my vehicle. That's the only thing you need. The tool identifies your exact year, make, model, and engine from it.
Get an instant legal verdict
You'll see a clear green light if a CARB-certified converter is available, the vehicle it matched, and the official EO number.
Shop the parts that actually fit
Every converter shown is certified, EO-numbered, and confirmed to fit your car. Add to cart with confidence. No cross-referencing required.
Reading the result
Every answer the checker can give you
The checker never leaves you guessing. Against the part you're looking at and your exact engine family, it returns one of five clear verdicts — a green light to buy, a red stop with a way forward, or an amber "confirm first." Here's what each one means.
Legal & verified for your car
This exact part's own certification lists your engine family. It's confirmed street-legal and direct-fit — add it to the cart with confidence.
Not this one — but we have legal ones
This part isn't certified for your engine family, so it won't get you through smog. Certified parts that do cover your car exist, though — the checker shows up to three, each a direct product link.
No certified part for your car yet
We hold this part's full application list, your engine family isn't on it, and nothing else certified is currently live for your vehicle. An honest "not yet" beats selling you a part that can't pass.
Can't be verified either way
We don't yet hold engine-family data for this part, so the checker can't confirm or rule it out. Check the manufacturer's application listing before you rely on it for smog.
Certified — confirm it covers your vehicle
The part carries a valid Executive Order, but that EO didn't resolve to your exact vehicle in our data. The certification is real; the vehicle match just needs a quick manual confirm.
Why five answers, not two
A converter's legality isn't always a flat yes/no in the data. Rather than fake a green light, the checker tells you exactly what it knows — legal, not-this-part-but-here-are-others, nothing-yet, or confirm-first — so you never install a part on a guess.
Quick how-to
What is an Engine Family Number, and where do I find it?
The Engine Family Number (EFN), sometimes called the "Test Group," is a code assigned to your engine's emissions configuration. It's the single most precise way to identify what your car needs, which is exactly why the checker uses it.
You'll find it on the Vehicle Emission Control Information (VECI) label, a sticker under your hood that is usually on the underside of the hood itself, on the radiator support, or near the strut tower. Look for a line that says Engine Family or Test Group:
Can't find the label?
No hood sticker? You can still get an answer. The checker lets you confirm your vehicle by year, make, model, and engine instead. Either path lands on the same verified result.
Good to know
How to read a CARB EO number
A CARB Executive Order number looks like D-193-157 or D-798-10. The letter-and-number format identifies the specific approval that makes a converter street-legal, and each EO lists the exact vehicles it covers.
You don't need to memorize any of this. The checker matches the right EO to your car for you. But when you see an EO number on a product page or a physical converter, that's your green flag: it's the mark of a genuinely certified part. If a converter can't show one, treat that as your answer.
Buy with confidence
Certified, direct-fit, and confirmed for your car
Every CARB-certified converter we sell is EO-numbered, emissions-legal in all 50 states, and engineered as a direct-fit replacement that bolts in using your original hangers and flanges, with no custom fabrication or welding.
Guaranteed emissions-legal
Each converter carries a valid CARB Executive Order, sold and shipped legally to California, Colorado, New York, and Maine.
Confirmed to fit before you buy
The checker matches parts to your exact vehicle, so you never gamble on cross-referencing a part number yourself.
Designed to pass & clear the code
Certified converters are built to satisfy the emissions readiness monitor and get you through smog the first time.
FAQ
CARB catalytic converter questions
Will a CARB-certified converter pass California smog?
Yes. A CARB-certified converter with a valid EO number covering your vehicle is exactly what smog stations and the DMV recognize as legal. Assuming the rest of your emissions system is working, a certified direct-fit converter is designed to pass.
Will a cheaper 49-state converter work in California?
No. A 49-state (federal) converter has no CARB EO number, so it's illegal to sell or install in California, Colorado, New York, and Maine, and it will fail smog. The upfront savings turn into paying for the job twice.
Do I really need my Engine Family Number?
It's the fastest and most precise way to get an answer, because it pins your exact emissions configuration. But it's optional. You can confirm your vehicle by year, make, model, and engine instead and reach the same verified result.
What's the difference between an EO number and an EFN?
Your Engine Family Number (EFN) identifies your car's engine, printed on your under-hood label. A CARB EO number identifies a converter's legal approval. The checker connects the two: it takes your EFN and finds the converters whose EO covers your vehicle.
Is a CARB converter legal in the other 46 states too?
Yes. CARB-certified converters are legal everywhere in the U.S. Buying certified is the safe choice no matter where you register the car, and essential if you ever move to or sell into a CARB state.
My check-engine light won't clear after a new converter. Why?
A common cause is a non-certified or wrong-fit converter that can't satisfy the vehicle's readiness monitor, leaving a P0420 or P0430 code. A certified, correctly matched direct-fit converter is built to resolve exactly that.
Check your car. Shop with certainty.
Confirm a CARB-legal converter exists for your exact vehicle in seconds, then buy the certified, direct-fit part that gets you through smog the first time.
Check my vehicle Shop CARB-certified converters