Will Catalytic Converter Cleaner Fix P0420? (Answered!)


Many car owners experience problems with the catalytic converter (P0420). Since catalytic converters can be quite expensive, many owners ask if a Catalytic converter cleaner will fix a P0420? It is a legit question.

In my opinion, before you change any part of your vehicle, you first need to see if a good cleaning will fix the problem. But, many times, the catalytic converter cleaners state that their products can fix a P0420 code.

Eager to find out more about this matter, I talked to a couple of mechanics that actually used catalytic converters in the past. Here is what I found out.

Will Catalytic Converter Cleaner Fix P0420?

Will Catalytic Converter Cleaner Fix P0420

Will catalytic converter cleaner fix P0420? Yes. If your catalytic converter is clogged up and the scan tool is showing a P0420 code, a catalytic converter cleaner will fix the problem. The catalytic converter gets clogged up by unburnt fuel going into the exhaust system, or oil or antifreeze making their way into the exhaust system and creating a thick carbon and soot which easily clogs up the air passages. A cleaner will clear the air passages inside the catalytic converter’s ceramic honeycomb and will fix the P0420 code.

Before you replace the catalytic converter which is a really expensive part, you might try cleaning it out first. When an inefficient catalyst code pops up (P0420), it can come up when you only lose 5% of its efficiency. The catalytic converter could still be working at 94% efficiency and it’ll trip the code. So, a little cleaning can often fix them.

How Long Can You Drive With Bad Lif...
How Long Can You Drive With Bad Lifters?

A clogged catalytic converter can overheat your engine because the exhaust gases are unable to pass through the catalytic converter and out of the exhaust pipe. Instead, they are staying inside the engine for a bit longer than they should, therefore making it run a bit hotter.

There are a lot of catalytic converter cleaners, but I have used the Motorkote brand which I got from amazon.com. The best way to clean a catalytic converter is to pour the catalytic converter into a full gas tank and either drive the car for about 150 miles at higher speeds or run the engine at about 2,500 RPMs for about 30 minutes. That should be enough for the cleaner to run through and burn the impurities out of the catalytic converter and make it work again.

Will The Check Engine Light Go Off After Cleaning The Catalytic Converter?

Will Catalytic Converter Cleaner Fix P0420

Will the check engine light go off after cleaning the catalytic converter? Yes. When the catalytic converter gets clogged up, it triggers an error code P0420 which is displayed as a check engine light on the dashboard. However, when you clean the catalytic converter and fix the issue, the vehicle computer will run tests and if cleaning the catalytic converter solved the issue, the check engine light will go off.

The catalytic converter plays a huge role. It cleans the exhaust gases from the combustion chamber before releasing them into the atmosphere. In many states, it is actually illegal to drive with a bad catalytic converter. So, being exposed to exhaust gases all the time, the catalytic converter usually gets clogged up after 50,000 miles. When it does get clogged up, it triggers a check engine light and a P0420 code.

It takes for a catalytic converter to fail two times to trigger the check engine light on the dashboard. By cleaning the catalytic converter and actually fixing the problem, it will take the catalytic converter up to 40 passes for the computer to turn off the check engine light.

The catalytic converter has a honeycomb made out of platinum, palladium, and rhodium. These metals filter out the harmful exhaust gases before releasing them into the atmosphere. Over time, the honeycomb gets carbon deposits build-up on it and stops working correctly. The hot exhaust gases can’t pass through the catalytic converter and stay in the engine for a longer period which can it to overheat. This immediately triggers a check engine light (P0420 code) and has to be fixed immediately.

In most cases, cleaning the catalytic converter will fix the issue and will make the check engine light go off.

Can I Drive My Car With a P0420 Code?

Will Catalytic Converter Cleaner Fix P0420

Can I drive my car with a P0420 code? Yes. You can drive your car with a P0420 code. However, you will experience sluggish engine performance and reduced acceleration. Often, you will see a dark exhaust smoke from the tailpipe and a smell of sulfur or rotten eggs. Plus, vehicles with a P0420 code can’t pass the emission test because the catalytic converter isn’t working properly and isn’t filtering out the harmful exhaust gases.

All the harmful exhaust gases that exit the engine and pollute the environment go through the catalytic converter. The catalytic converter is built from precious metals that cause chemical reactions and they change the harmful gases into less harmful gases before releasing them into the atmosphere. Driving with a bad catalytic converter and a P0420 code means that you are deliberately polluting the environment. The only scenario where it is okay to drive your car with a P0420 code is to the repair shop.

Driving your vehicle with a P0420 code is not going to be the same. The exhaust gases that are meant to go through the catalytic converter and out of the exhaust pipe won’t be able to do so. Instead, they will get to the catalytic converter and bounce back into the engine. This means that at this point, your engine has more hot exhaust gases in it and can overheat at any moment.

Symptoms like sluggish engine performance and reduced acceleration are often present when the catalytic converter is bad. While in reality, you can drive your car with a P0420 code, the experience won’t be the same. Many times you will notice black smoke out of the tailpipe and a rotten eggs smell. Plus, if your vehicle is up for an emissions test, rest assured that it will fail it.

Car Care Hacks

Hi there. I am a certified Automotive Service Excellence (ASE) mechanic since 2018 and a car detailer for 10 years.

Recent Content