Po420 code, anyone have a idea?

[MarcoFuc]

anyone have a idea what might be causing this? I was thinking o2 sensor but been reading and it says typically it would show a code for the sensor or a bad cat? Would this get triggered on if I have a exhuast leak?

 

[Jeepwalker]

Could be. Is the leak at the exh manifolds?

Does your truck use any coolant by chance?

 

[metalchewy]

Its a catalytic converter code but something has to have caused it.

From the research on this and other sites that I did, causes of a dirty cat could be rings, wore out cylinder walls, head gasket, spark plugs, valve stem seals, injectors, manifold leaks, and few other things.

I had a puff of smoke at times after running it hard. On my '10 4.7 it seems to have been valve stem seals causing a dirty cat. Then I ran a good fuel system cleaner through it that also cleans the cat.

Im only On the third week without the code now, so far so good. Fingers crossed it stays that way.

 

[GTyankee]

https://www.autocodes.com/p0420_dodge.html

i think this should be tried first

Getting Rid of Code P0420 With A Little Spring Cleaning

A good cleaning might be all you need to get rid of code P0420.This video is sponsored by RisloneUnderhood Service: https://www.underhoodservice.com/Rislone:...

www.youtube.com

I found this interesting, i had not heard of it before

How to Fix P0420 Engine Code in 3 Minutes [3 Methods / Only $19.99]

============================Claim your FREE engine code eraser ð https://free.nonda.co ð== How to Fix P0420 ===========Engine Code P0420 Saving Repair Part...

www.youtube.com

 

[sullivan]

So I had this on a 2010 Challenger SRT8. It ended up being a series of wild stuff, so I am not sure this applies to you.

I changed the O2 sensors and it didn't help. It ended up being a fried / faulty PCM that got messed up during some electrical work. I had to fight with the dealer to get it replaced under federal law as it was within the federal law warranty.

When the PCM fried, it ran really weird. And ended up physically damaging the cat.

Once the PCM was replaced it ran like it should, I ordered new aftermarket high flow cats and discovered one of the factory cats got destroyed. It was wild seeing the cat and that the car was running fine.

I am still not sure the exact cause but essentially I heard a loud pop, almost like explosion. I think it was running too rich... idk

What a headache that was.

____________________________________________________________________________________________________

What I would do is check your O2 sensors first. Do not replace them with aftermarket ones. I recommend buying OEM O2 sensors. I got mine online versus the dealer and I saved a lot of money. I think I got them from Napa or Advanced auto.

 

[metalchewy]

https://www.autocodes.com/p0420_dodge.html

i think this should be tried first

Getting Rid of Code P0420 With A Little Spring Cleaning

A good cleaning might be all you need to get rid of code P0420.This video is sponsored by RisloneUnderhood Service: https://www.underhoodservice.com/Rislone:...

www.youtube.com

I found this interesting, i had not heard of it before

How to Fix P0420 Engine Code in 3 Minutes [3 Methods / Only $19.99]

============================Claim your FREE engine code eraser ð https://free.nonda.co ð== How to Fix P0420 ===========Engine Code P0420 Saving Repair Part...

www.youtube.com

I tried the first cleaning method in the second video last year and it got me through emissions testing and 3 months later started throwing the CEL with the code again. I actually went looking for the cause after that and hope I found it.

I Hadn't seen the 02 Extenders before. Thanks. If I didn't find the true cause and it comes back I know what to try next year.

 

[MarcoFuc]

Could be. Is the leak at the exh manifolds?

Does your truck use any coolant by chance?

I do know I have a bolt messing cause it's stripped but that's been like that for months. And not that I have noticed no.

 

[Delta11]

After watching some utube videos I read the label on the Cat Cleaners...Stated Naptha and Benzene. So I bought two gallons of Xylene from hardware store...$25 per gallon. Poured them in at 1/4 tank...I have a 33/34 gallon tank. 2010 2500 5.7 Longhorn. Anyway it did the trick. Must have cleaned tha Cat. O2 sensors are new. P0420 went away. Ran the truck immedialy down the road and ran it almost empty and then refilled. Was a little timid about hurting any plastic.rubbers,etc...even though Xylene is in gasoline.Scotty Kilmer talking about using Laquer Thinner in gas to clean Cats put me on this road.

 

[metalchewy]

After watching some utube videos I read the label on the Cat Cleaners...Stated Naptha and Benzene. So I bought two gallons of Xylene from hardware store...$25 per gallon. Poured them in at 1/4 tank...I have a 33/34 gallon tank. 2010 2500 5.7 Longhorn. Anyway it did the trick. Must have cleaned tha Cat. O2 sensors are new. P0420 went away. Ran the truck immedialy down the road and ran it almost empty and then refilled. Was a little timid about hurting any plastic.rubbers,etc...even though Xylene is in gasoline.Scotty Kilmer talking about using Laquer Thinner in gas to clean Cats put me on this road.

I ran BG-44K through mine to clear it. 9 months later a second can and have been good since, and didn't replace my O2 sensors at all. But I did have some valve stem leakage that I fixed in between round one or two. To try to prevent it.

Added the wow, because it did have a xylene or thinner odor when I smelled the can. I'd worry too much adding that much thinner to a vehicles tank, even flex fuel vehicle . Glad it worked out for you.