If you’re a Toyota Prius owner and haven’t had your catalytic converter stolen, consider yourself lucky. With a huge increase in reported thefts in 2021, there’s no sign of catalytic converter theft slowing down in 2022.

If it hasn’t happened to you, be aware: it’s not just media hype. The Highway Loss Data Institute (HLDI) has recently published a report that indicates a 40x increase of insurance claims in a 4 year period for the 2004-2009 Toyota Prius. 40 times increase!

I’ve heard about it, but until my catalytic converter got stolen I never thought I’d worry about it.

So whether you’ve had your catalytic converter stolen already, or drive a Prius and need some facts, here’s some straight forward answers about your Prius catalytic converter, replacement and how to protect your catalytic converter.

What is a Prius Catalytic Converter?

Yes, your Prius has a catalytic converter. Or had a catalytic converter until it got stolen.

A catalytic converter is part of your Prius exhaust system. It’s function is to convert raw exhaust from your engine into cleaner emissions coming out of your tailpipe and into the environment.

Your catalytic converter works by heating up metal catalysts to 500-1200 degrees Fahrenheit, causing a chemical reaction to convert that harmful engine exhaust to clean tailpipe emissions.

Where is the Catalytic Converter on my Prius?

Here’s a helpful summary of your Prius exhaust system and the major components, starting at the front of the car and working towards the rear: Engine > Manifold > Catalytic Converter > Resonator > Muffler > Tailpipe. These components are connected by series of pipes, about 2″ around.

The catalytic converter on your Prius is underneath your car and runs down the center of your car, starting around your front wheels and ending about midway through the length of the car.

Your Prius actually has two catalytic converters, joined by a small run of pipe. This whole unit is usually referred to as “the catalytic converter” on a Prius.

The first cat peeks out at an angle from the engine area, and the second is in plain view, right about where the back of your front seats are.

Prius catalytic converter replacement cost.

If you need to replace the catalytic converter on your Prius you can be in for a surprise. Depending the year of your Prius, it can cost $500 if done with an aftermarket catalytic converter at an independent garage. That number can climb all the way to $4,000 if you use an OEM cat converter at a Toyota Dealer.

Why are Prius catalytic converters being stolen?

There is no definitive list of the most stolen catalytic converters. From police and media reports, its generally accepted that the Toyota Prius is the number one car for catalytic converter theft. There is no model year of Prius that is safe.

Other popular vehicles on the most stolen list are the Honda Element, Toyota Tacoma & Tundra pickup trucks and Honda Accords.

Each vehicle has it’s own reason why it’s a target for catalytic converter theft, but here’s the reason why thieves steal Prius catalytic converters.

As you read above, the exhaust uses metal catalysts in the cat converter and are a combination of platinum, rhodium, palladium and other precious metals.

Thieves aren’t stealing catalytic converters to resell as car parts. They’re selling to scrapyards and metal processors to extract the trace amounts of precious metals.

Although a catalytic converter only contains a few grams of these metals, it can add up. At the time of this writing, Palladium is around $2000 per ounce and Rhodium is at almost $12,000 per ounce.

That $12k is not a typo!

It can cost upwards of $4,000 dollars to replace your Prius catalytic converter.

There are theories out there about why the Prius is a big target for Catalytic converter theft.

One theory is that because the gas engine doesn’t work as much, the precious metals don’t wear out as much (I don’t buy this one).

The second, and most likely, is that because the Prius doesn’t rely on the gas engine full time, the catalytic converter may not get hot enough all the time to run efficiently. As a result, more of the precious metals are needed to make up for this lack of efficiency.

So, how much is a Prius catalytic converter worth? A 2nd Gen Prius Catalytic converter is worth as much as $1,000 on the scrap market compared to $100-200 for some other vehicles

The bottom line: A Prius catalytic converter can be stolen in less than a minute and it’s more valuable than most other vehicles.

How can I tell if my Prius catalytic converter has been stolen?

This is an easy one. You’ll know it as soon as you start your Prius. You’ll hear a loud grumbling noise from underneath your car. A very loud grumble. Some people think their Prius muffler has been stolen, but that’s not the case.

With your cat converter gone, the muffler doesn’t get to do it’s job of, well, muffling the engine sounds.

Along with the noise, the check engine light (CEL) on your dash will light up as well.

A catalytic converter has an oxygen sensor that ties into your Prius electronics, and chances are that oxygen sensor was stolen with the catalytic converter, activating your vehicle’s check engine light.

If you look underneath your car where the catalytic converter should be, you’ll see big, empty space.

Can I drive my Prius without a catalytic converter?

In general, it’s not a good idea to drive ANY vehicle without a catalytic converter for any amount of time. It’s not good for your car over the long term and bad for the environment. Not to mention incredibly noisy and against the law.

If you need to drive for a short time, it may be ok to drive without a catalytic converter.

But let’s go back to your Prius. So, your Prius catalytic converter was stolen and you’re wondering if it’s ok to drive to the garage to get it fixed. The answer is….

Yes and No.

The Prius comes in different “generations” depending on your model year.

• 1st Gen are 2001-2003 Prius
• 2nd Gen are 2004-2009 Prius
• 3rd Gen are 2010-2015 Prius
• 4th Gen are 2016-Current Prius.

If you have a 1st or 2nd Gen, you’ll be ok driving your Prius to the dealer or Mechanic to get this mess taken care of.

The noise may be embarassing, but as long as there’s nothing hanging down from the bottom of your car, you should be ok.

If you have a 3rd Gen or newer Prius, DO NOT DRIVE IT if your catalytic converter has been stolen!

I repeat..Do not drive your 2010-2015 Prius or your 2016-2022 Prius if your catalytic converter has been stolen!

Here’s why: The newer Toyota Prius models have engine coolant lines running to the catalytic converter. Most likely, when the thief stole your catalytic converter he cut those very important coolant lines.

Driving your 2010+ Prius with those lines cut may do serious damage to your engine.

Whichever generation of Prius you drive, call a tow truck if you can’t identify your model year or the amount of damage done.

Toyota Prius Catalytic Converter Protection

Preventing your catalytic converter from being stolen isn’t as simple as installing an alarm, a catalytic converter shield, lock or other device. It’s a combination of physical devices and strategy to protect your catalytic converter.

You can check out this earlier article that covers all the bases and the devices on the the market today.

The quick story is that thieves are stealing cat converters for two main reasons: It’s easy to do and it pays well. In less than a minute, your catalytic converter can be stolen.

An alarm for your catalytic converter won’t stop a thief by itself. Neither will things like etching your catalytic converter or painting it a bright orange color.

As a Prius owner, the best protection is to make it as difficult as possible to steal your catalytic converter by installing a physical anti-theft device.

Catalytic converter anti-theft devices come in two basic forms: Cat Shields / protection plates and Cat Locks / Cat Clamps.

A shield covers your catalytic converter, preventing thieves from cutting out your cat converter. A cat clamp attaches to the catalytic converter and secures it to the undercarriage of your vehicle.

Do cat shields really work? Is a cat lock worth it? Given enough time and the right situation, any anti-theft device can be defeated. By installing a visual anti-theft device, a would-be thief may move on to an easier target.

That’s the best you can hope for.

The Best Catalytic Converter Shields for Prius

MillerCat CatShield for Prius.

MillerCat got their start making aftermarket catalytic converter replacements and expanded into the anti-theft market. There are several companies making catalytic converter shields, and if catalytic converter protection isn’t your thing they may all look the same.

When I was looking for Prius Cat Shields, i noticed some outstanding features on the MiilerCat that set them apart from less effective competitors.

Designed for a custom fit, easy installation and clear instructions for your specific model Prius. If you’re comfortable safely changing your oil and working under your car, install can be a DIY job with a few simple tools.

Since we’ve first published this article, clever catalytic converter thieves have figured out a new way to quickly and easily get around the typical flat catalytic converter shield. Miller Cat has updated and improved on their Gen1 and Gen2 Prius shields to help thwart this new theft method.

If you’re unsure about working on your car, MillerCat has an installer network, and some are even Toyota Dealers.

On certain models, MillerCat offers a Stainless Steel option. Its a little more expensive than the Aluminum models, but Stainless steel offers more resistance to cutting tools.

Thermal Testing. This was the big highlight for me. A catalytic converter does its job by using heat. A lot of heat. But too much heat can damage your catalytic converter. If you put a some kind of cover on it, that heat has nowhere to go.

MillerCAT products go through rounds of testing and design to make sure your Prius cat stays safe.

Security hardware options. MillerCat provides security bolts with an uncommon head that can’t be removed by common tools. As an option, they take it one step further by offering a proprietary custom screw that they have developed. with either option, they include the necessary tool in case your Cat Sheild needs to be removed to service your Prius.

MillerCAT is US company with excellent support. Cat Shields are designed and manufacutured in house. Although excellently designed, this isn’t a complicated piece of machinery. Once it’s on your Prius, you’ll probably never have to worry about it again. But things happen. Damage in shipping, maybe questions about install. In any case, if you have a question, there’s a real live person on the on the other side.

Extra bonus: At the time of writing MillerCat is offering free shipping in the continental US and most orders ship same or next day! Expedited shipping is available.

UPDATE: MillerCat heard about us and has offered us a discount code for our readers. Order your CatShield direct and use Discount Code : GEARIST

MILLERCAT 2001-2003 Prius Gen 1 Cat Shield

A two piece shield offering the most protection for your Gen 1 Toyota Prius. Available in Aluminum with the Option for the custom high security screw kit.

Comes with Cat Shield, custom bracket, installation hardware.

Not sure that a do it yourself install is for you? Take a look at the instructions to see what you’re getting into.

In response to new methods of theft, they have developed the Deadbolt add-on. This add on protects and reinforces the front of your cat converter from being cut.

MILLERCAT 2004-2009 Prius Gen 2 Cat Shield

Now available in a “Version 2” design. The new design is an evolution to protect from new methods of theft. Not just a single flat plate, Version 2 is a four piece kit to reinforce vulnerable areas for further protection.

This is unlike anything else on the market for your Prius.

The Gen 2 plate is available in both Aluminum or Stainless Steel with the option for the high security screw kit.

Comes with Cat Shield, installation hardware, tamper-proof screw kit.

Check out the install instructions here

MILLERCAT 2010-2015 Prius Gen 3 Cat Shield

Like the Gen 2 plate above, the Gen 3 is available in aluminum or stainless steel and the option for a high security hardware kit.

Includes the Cat Shield, installation hardware, tamper-proof screw kit.

If you’re thinking about a DIY install to protect your catalytic converter, see whats involved and see the install instructions here.

MILLERCAT 2016-2022 Prius Gen 4 Cat Shield

The Gen 4 is designed for both the Prius Liftback and Prius Prime models.

Available in Aluminum or stainless steel. with the option for the MillerCAT high security hardware.

This model is an easy install, with no drilling involved. See the install instructions here,

Comes with Cat Shield, installation hardware

MILLERCAT 2012-2017 Prius V Cat Shield

MILLERCAT 2012-2019 Prius C Cat Shield

So If you’re looking for a quick recommendation for a Prius specific device, check out the CatShield from MillerCat.

It’s a “best in class” shield made specifically for your Prius. They’ve got competitive pricing on the low end, and additional options to insure that your Prius is as safe as it can be.

Final Thoughts

No matter what you do, it’s important to protect your Prius catalytic converter from theft. Replacement costs are high, not to mention the inconvenience. So if you’re looking to see what you can do to prevent theft, read this earlier article that covers some catalytic converter anti theft strategies!

Questions? Comments? Tell us below!