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What Is The Catalytic Converter?

Cross section of catalytic converter with sensor flue gas
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What Is A Catalytic Converter?

A catalytic converter is a part of your car’s exhaust system. Its job is to remove the harmful pollutants from your exhaust before the exhaust leaves your muffler. All gasoline cars built after 1974 are required to have a catalytic converter. Catalytic converters reduce pollution and make the air safer to breathe.

Where Is a Catalytic Converter Located on a Car?

 Your catalytic converter is between the engine and the muffler underneath the vehicle. They are usually near the front of the vehicle. If you are under your car, you should be able to see the catalytic converter. This placement and its high cost makes it a common target for theft.

What’s Inside A Catalytic Converter?

The inside of a catalytic converter usually looks like a ceramic honeycomb. The honeycomb walls are coated in precious metals like rhodium, platinum, and palladium. These precious metals are what convert the pollutants to less harmful chemicals.

What Does A Catalytic Converter Do?

Your engine produces harmful pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides. The catalytic converter converts these chemicals into less toxic chemicals like CO2 and water. To pass emissions tests and inspections, you need to limit the amount of these harmful chemicals you release into the air.

How Does A Catalytic Converter Work?

A catalytic converter works by splitting up the harmful chemicals and putting them back together as safer chemicals. For instance, your catalytic converter will convert nitrogen oxides into nitrogen gas and oxygen gas. These are the gasses the air is naturally made of. Some harmful chemicals do remain in the exhaust.

Can You Drive Without A Catalytic Converter?

You can drive without a catalytic converter if you replace the section with a straight tube. While you may only have a decrease in mileage and engine performance, this is illegal. Since 1974, all vehicles are required to have a catalytic converter to reduce the amount of pollution cars emit.

Driving without a catalytic converter is illegal even in areas that do not require emissions testing. You can be fined for driving without a catalytic converter. Any reputable shop will not work work on your car if they see you’ve removed your catalytic converter.

What Cars Have A Catalytic Converter?

All gasoline cars built since 1974 are required to have a catalytic converter. This includes hybrids because they have engines too. Electric vehicles don’t have catalytic converters because they don’t have an exhaust system. Diesel vehicles also usually have catalytic converters, but they work differently.

How Much Does A Catalytic Converter Cost?

Catalytic converters usually cost between $400-$2400. The wide cost range is due to a few factors:

  • Direct-fit vs universal-fit
  • CARB vs EPA standards
  • Hybrid vehicle vs non-hybrid vehicle

The factors that make a catalytic converter more expensive are direct-fit, CARB compliant, and if it is built for a hybrid vehicle.

Direct-Fit vs Universal-Fit

A direct-fit catalytic converter is generally more expensive than a universal-fit catalytic converter. Direct-fit means that it is designed specifically for the vehicle you’re putting it on. This makes it easy to remove and install a new one. Universal-fit means it is designed to fit a wide range of vehicles.

A direct-fit catalytic converter comes with bolt holes that align perfectly with the bolt holes of your car. All you need to do is unbolt your existing catalytic converter and place the new one in the same place. This is a relatively easy repair that you can try at home without specialty tools.

A universal-fit catalytic converter is made to fit a wide range of vehicles. This keeps the price down because they can be made in greater quantities. They are more complicated to install though. Universal-fit catalytic converters don’t have a way to bolt into your exhaust system. You will need to cut out a section of your exhaust and weld in the new catalytic converter.

Something to keep in mind is that even though they are called universal-fit catalytic converters, they do not fit all vehicles. Make sure you check that the universal-fit catalytic converter you buy fits your model.

We compared the cost difference of a direct-fit and universal-fit catalytic converter for a Toyota Corolla. The cheapest universal-fit catalytic converter we could find was $221.99. The cheapest direct-fit catalytic converter we could find was $744.99.

CARB vs EPA Standards

All states require cars to meet EPA (Environmental Protection Agency) standards for emissions. CARB (California Air Resources Board) is a stricter standard that some states have on top of the EPA standards. Because they are stricter, CARB compliant catalytic converters have to be more efficient and are more expensive.

 We compared the cost difference of a EPA compliant and CARB compliant direct-fit catalytic converter for a Toyota Corolla. The cheapest EPA compliant catalytic converter we could find was $744.99. The cheapest CARB compliant catalytic converter we could find was $1244.99. 

If you live in a state that requires CARB compliant catalytic converters, you may not need one. The regulations usually affect newer models. For instance, in Maine, only car models 2001 or newer need to be CARB compliant.

Below is the full list of states that require CARB compliance and what model years they apply to:

StateModel Years
CaliforniaAll Years
ColoradoAll years
Connecticut1998 and newer
Delaware2014 and newer
Maine2001 and newer
Maryland2011 and newer
Massachusetts1995 and newer
New Jersey2009 and newer
New York1993 and newer
Oregon2009 and newer
Pennsylvania2008 and newer
Rhode Island2008 and newer
Vermont2000 and newer
Virginia2025 and newer
Washington2009 and newer

Hybrid Catalytic Converters

Catalytic converters for hybrids are usually more expensive. Catalytic converters in hybrids don’t get as hot as they do in non-hybrids because the engine isn’t always running. Because the exhaust going through a hybrid catalytic converter is colder, more precious metals are needed, which increase the cost of the part.

Some cars even have two catalytic converters. For cars that have dual exhaust systems, there will be a catalytic converter for each one.

Why Do People Steal Catalytic Converters?

Catalytic converters are a commonly stolen car part. Thieves target this part because it is easy to reach and contains precious metals like rhodium, platinum, and palladium. These metals can be worth more per oz than gold. Depending on the condition of the metals, a thief can sell the part for over $1000.

What Cars Are Most Likely To Have Their Catalytic Converters Stolen?

Some cars have a higher risk of getting their catalytic converter stolen. Cars that sit high off the ground like SUVs, minivans, and trucks make it easier for thieves to reach the part. Hybrids are another target because their catalytic converters have more precious metals so they can be sold for a higher price.

How To Prevent Catalytic Converter Theft

A thief can remove your catalytic converter in less than a minute. You can make it harder for them by parking over a puddle or in a private area. You can also install a catalytic converter guard that makes it harder for them to cut off the catalytic converter.

Does Insurance Cover Catalytic Converter Theft?

A stolen catalytic converter will probably be covered by comprehensive car insurance. If you have an older car the insurance company might declare the car totaled because of the high expense of the repair. You can read more about what to do when your car is declared totaled.

Common Problems With Catalytic Converters

There are three main types of problems your catalytic converter can have.

  • Overheating
  • Clogged
  • Damaged

These problems might cause your check engine light to turn on. You should fix these problems as soon as you can. A malfunctioning catalytic converter can decrease performance. It might also cause serious engine problems.

Is My Catalytic Converter Overheating?

Catalytic converters can overheat when there are engine misfires (P0300, P0301, etc.) or lean or rich air/fuel mixtures (P0171, P0171) . Malfunctioning oxygen sensors may also make a catalytic converter overheat. You should fix the cause of the overheating before you replace the catalytic converter.

Is My Catalytic Converter Clogged?

Your catalytic converter might be clogged if you notice:

  • A rotten egg smell
  • Black smoke from your exhaust
  • Decreased fuel efficiency

Your check engine light might also come on with error code P0420.

If you catch the clog early you may be able to clean the catalytic converter to solve the problem.

You can clean the catalytic converter in two ways.

  • You can remove the catalytic converter and use a pressure washer on low pressure to remove dirt from the part.
  • If you don’t want to remove the catalytic converter, you can use a catalytic converter cleaner. You put the catalytic converter cleaner in your gas tank. Follow instructions from whatever cleaner you buy.

Is My Catalytic Converter Damaged?

If the catalytic converter is damaged you might see your check engine light turn on with code P0420. You might also see rust, holes, or other physical damage on your catalytic converter. If there is damage to the catalytic converter you will likely need to replace your catalytic converter.

Catalytic Converter ProblemDIY or MechanicResources
Catalytic converter is overheatingMany of the possible repairs are possible at home. See if you can rule out a harder repair before taking it to a mechanic.Misfires: P0300
Lean Air/Fuel Mixture: P0171
Rich Air/Fuel Mixture: P0172
Catalytic converter is cloggedMany of the possible repairs are possible at home. See if you can rule out a harder repair before taking it to a mechanic.Catalyst System Efficiency Below Threshold (Bank 1): P0420
How to clean a catalytic converter
Catalytic converter is damagedYou can try to replace a catalytic converter at home.How to replace a catalytic converter

FIXD Research Team

At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.

We’re here to help you simplify car care and save, so this post may contain affiliate links to help you do just that. If you click on a link and take action, we may earn a commission. However, the analysis and opinions expressed are our own.

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FIXD Research Team

FIXD Research Team

At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.

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