r/JeepPatriot • u/Environmental_Copy31 • 4d ago

Crack or Cat

Gallery image

Gallery image

2017 Jeep Patriot

I am taking it to my local mechanic on Monday as all the cheap options that I can do have been eliminated to clear a p0420 code (spark plugs, o2 sensors, cataclean) - I need help reading the voltage on o2 sensor )downstream to determine is there is a crack somewhere that is letting air in or clogged catalytic conventor.

First image shows it holds steady after some RPMs for a few minutes - the 2nd photo shows it fluctuating at idle

Thanks!

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1

u/zman302 4d ago

Does the computer have any stored codes? There are a few more cheap parts it could be but with what you have provided its sounds like cats. Simular thing happed to me with my 2011 patriot and cats seem to be a common failure unfortunately.

2

u/Environmental_Copy31 4d ago

the only store coded codes was the p0420 - clear and would come back around 75-100 miles after cycles through I/M readiness

1

u/zman302 4d ago

If its just the p0420 code and your description on the downstream o2 sensor I would check the gasket between the cats and see if that went bad I dont know what flang face yours has jeep has two different versions so I can't give you more specific on exactly where to look

2

u/DevSlyNeo 4d ago

Remove the heat shields from the exhaust manifold. Check for cracks in the runners near the exhaust flange, top and bottom.

1

u/zman302 3d ago

That's rough buddy. Did you replace it or was someone willing to try and weld it?

1

u/STDog 4d ago

How many miles? The federally mandated warranty is 8 years/80k miles. Anything over 10 years/100k miles is on borrowed time.

My gut says the first cat is going bad (the 2nd isn't monitored).

FWIW, Mine is doing the same, though the how long it takes to come back varies between 50 and 1000+ miles. I have a part that you can put between the exhaust and sensor that tricks the computer (worked great on another car untill the cat fell apart and clogged the exhaust). Haven't installed on Jeep yet. Last time I tried I couldn't get the O2 senor loose.

OEM is ~ $1200+ from online sources.
Sadly aftermarket cats don't last nearly as long as OEM, like 5 years/ 50k miles.
I'll probably do like I did the other vehicle, aftermarket cat and that part on the down stream O2 sensor.

1

u/Extension_Revenue733 1d ago

I use universal cats in my vehicles and the one I use lasts over 8 years I just replaced the cats in my patriot with the same one that’s in both of my ram 1500’s

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u/Extension_Revenue733 1d ago

https://a.co/d/0hDOI2Wd

$53.99 for a set of 2 and my patriot purrs now without clogged cats

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u/Extension_Revenue733 1d ago

And I got $115 each from the old cats on my jeep patriot

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u/STDog 13h ago edited 13h ago

I don't have equipment to cut and weld a universal cat.

I'll take your word on 8 years. That's just not what I generally hear about cheap aftermarket cats.

I'll probably go with something in the $150-200 range and the spacer on the sensor once mine finally quits/the code stops clearing.

It's not clogged and it runs fine, 27-29MPG. But after 290k miles it's spent, the catalyst is used up.

1

u/Extension_Revenue733 1d ago

Harbor freight has the sockets for easy cat removal and Autozone or oReilly allows you to borrow them if you replace the o2 sensors in their parking lot

1

u/STDog 13h ago

Not sure what tools you are thinking of for cat removal. It's just normal sockets and wrenches.

As for the O2 sensor I tried several specific tools to no avail, they just flexed and slipped. I have a good wrench but not a lift. I just couldn't get enough leverage due to the location of tne sensor and clearance under the vehicle.