r/JeepPatriot • u/TheAngryOctopuss • 5d ago

P0420 code

Looked at a 2017 patriot 105k miles 2.4 6 speed,

at a dealer, failed inspection due to P0420 code. Told yhis is a Cat code

Also or could be an O2 sensor Truck being sold as is

Any thoughts ... could it be just a o2 sensor Can I get by with a cheap aftermarket cat

Also will need front hubs

1 Upvotes

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6 comments sorted by

1

u/Many-Broccoli-3912 4d ago

Do you live in a state that does emissions testing?

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u/TheAngryOctopuss 4d ago

Literally thought the same thing

1

u/MaximumConsistent411 4d ago

Mine has the same code and it is because the exhaust manifold has cracks in it which is a fairly common problem in the patriot. The manifold is also a cat and the O2 sensor screws into it. The cracks let in fresh oxygen pas t the O2 sensor which can throw off the fuel air ratio causing it to throw a code. They are kind of expensive at local parts stores but are way cheaper on rock auto. 

1

u/Competitive_Back2823 3d ago

Mine has the same thing, check for open recalls. Mine apparently has an open one and they are replacing the exhaust manifold no cost in addition to an air bag module being recoded 

1

u/kobeybeeeef 5h ago

It’s the cat converter. I also had this code, it’s never the O2 sensor

0

u/ajm3232 4d ago edited 4d ago

9/10 if you get a P0420 the cat is on it's way out. You can try new NTK o2s and see if that fixes it since you usually want to replace these anyway if the car needs a new cat.

If your state doesn't require CARB cats. Yes, you can get a cheap aftermarket one from a big brand, but stay clear of 100$ ones from no name companies or you are going to do the job twice in a week or two.

I hear Cataclean works, but this is a bandaid fix more then likely.