PO420 fix suggestions

Hi guys,
OK, got the PO420 and deciding the best course of action to clean the cat converter.
I should say it doesn’t seem to be causing any problems yet and I’ve read to code can be triggered if the cat is operating an even a 5% loss of efficiency (Is this right?).
Lots of crazy fixes online of course.
So, I’m thinking of using a cat cleaner (any suggestions? One site says Cataclean 120007 Complete Engine, Fuel and Exhaust System Cleaner is best) and also doing a big-time cleaning of the throttle body, so I burn efficiently and don’t clog again.
But will the the cat cleaner typical work if I follow directions and if the cat converter is not to clogged?
Do these cleaners work?
I’m trying to avoid attempting to pry loose the converter and knock the carbon out with a broom handle (yes, that was a suggestion online).
Any thoughts would be appreciated.

That code can be representative of a variety of problems. Proper diagnosis for a proper cure. I would spend the money on a qualified mechanic finding the cause and not bet on miracle in a can.

Just call a couple of independent muffler shops ( no chain stores ) and see what a replacement cost is.

That’s a guaranteed way to destroy the cat.

There are occasional reports that those cleaners work. It may be worth a try.

I wouldn’t be busting out the cat if it’s bad. It won’t turn off the Check Engine light anyway.

Instead, if the cat is replaced, take the old cat to an auto recycler and recycle it. It could be worth up to $100.00. Depending on the size.


I don’t know about your area but where I live the only way you can recycle a old cat is if you have a repair bill for replacing a cat from a licensed shop or are a licensed repair shop.

As stated previously, that code may mean a bad cat, but there may be something else causing the condition. New cat does not solve an underlying problem.

Thanks all.
Yeah, I had no intention of hitting the cat with a broom stick or anything else. Replacement cost is $300, which I don’t mind, just hate replacing things that really aren’t broken.
Thanks Barkydog.I did have a real mechanic do a analysis and they said it is most likely a small leak somewhere causing the PO420 code.
Think I will try the cleaner as I’ve not read it could hurt.
And since there are no idle, stalling, acceleration issues with this,
Thanks all.

Most times I have a replaced the O2 sensor or the cat, depending on what had failed. One time I got a code and dumped a can of Cataclean into the gas tank and followed the instructions. It actually worked for several thousand miles. I sold the vehicle six months later and the code never came back while I owned it. I was a skeptic, but I guess these “miracles in a can” sometimes do what they say. For $25, it’s worth a shot.

On the other hand, it is worth knowing what is causing your issues, since not fixing the underlying cause will result on more codes and aggravation.

Most often a P0420 is caused by an exhaust leak… It may be leaking without your knowledge and if so…you found the cause.

Thanks Honda_Blackbird and bloody_knuckles.
As I said, was originally told by a mechanic it was leak, but I’m thinking with 254K on the CR-V a bottle of the Cataclean (used correctly) can’t cause any harm. If it is a small leak, it will wait till I truly need a muffler or pipes or both.
Thanks to everyone for your help.