Skip the auto shop - Our mechanics make house calls

What Does a Catalytic Converter Do?

catalytic converter

The modern automotive exhaust system is much more advanced than what was available even just a couple of decades ago. After recognizing that the average automobile was one of the primary sources of global pollution, the US government enacted the Clean Air Act, requiring that all vehicles manufactured after that date had to have an operational catalytic converter, among other important components. Your “cat” sits inline in the exhaust system of your car, quietly working away and reducing harmful emissions.

What’s it do?

The catalytic converter has one job: to reduce harmful emissions in your car’s exhaust to help mitigate pollution. It uses a catalyst (actually more than one) to convert harmful chemicals like carbon monoxide, hydrocarbons and nitrogen oxides into harmless substances. The catalyst might be one of three metals, or a combination of the three:

  • Platinum
  • Palladium
  • Rhodium

Some catalytic converter manufacturers are now adding gold to the mix, because it’s actually cheaper than the other three metals, and can offer better oxidation of some chemicals.

What’s oxidation?

Oxidation is used in this sense to mean “burning.” Essentially, the catalyst heats up to very high temperatures. These temperatures combine with the unique properties of the metals used as catalysts to create a chemical change in the unwanted substances. By altering the chemical composition, they’re made harmless.

Carbon monoxide (which is poisonous) becomes carbon dioxide. Nitrogen oxides are split apart into nitrogen and oxygen, two naturally occurring elements in the atmosphere anyway. Hydrocarbons left over from unburned fuel are turned into water and carbon dioxide.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...


Related questions

Q: can the pcm/ecu/ecm drain the alternator

No, the alternator provides voltage to the battery and other components. The PCM could possibly discharge a battery if it leaves a relay or another circuit on, but most likely is is not the cause of your alternator failure. If...

Q: replacement of catalytic converter

I wouldn't assume that the rear converter is bad unless the mechanic actually performed a diagnostic on the converter AND then explained to you what was done, what was found and WHY the solution is to replace the converter. If...

Q: Check Engine Light on, catalytic converter and O2 sensors need changing - $3000

Hi there: If you're Check Engine Light is coming on and somebody diagnosed this as a problem with your O2 sensors or the catalytic converter emissions system, it's highly possible that the trouble part are the front or back bank...