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Unread 09-01-2009, 10:13 AM   #1
valacech
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Code P0420 and Rattling Underneath

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Unread 09-01-2009, 11:09 AM   #2
TheBoogieman
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If the main Cat is rattling,just replace it with the Magnaflow.The $100 replacements are for the 97-99 models.On my old Jeep,it was welded on and I cut it off.The Magnaflow has nice wide clamps that work very well.
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Unread 09-01-2009, 01:17 PM   #3
mouse
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P0420 is the cats look here.
http://www.jeepforum.com/forum/f9/fa...-codes-778086/
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Unread 09-01-2009, 03:53 PM   #4
valacech
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Boogie: So I can basically just cut that sucker out of there (measuring correctly of course) and the hardware that comes with their system will enable me to clamp it in place with no leaks? Sounds too good to be true...
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Unread 09-01-2009, 04:47 PM   #5
tooofast
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I think its this one you need right?

Magnaflow 23227 - MAGNAFLOW Performance Direct Fit Catalytic Converter for 97-99 Jeep® Wrangler TJ with 4.0L Engine - Quadratec

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Unread 09-01-2009, 07:27 PM   #6
valacech
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I've got a 2004 though. This is such a pain in the neck. It's got the two mini catalysts and then the down pipe. Do I even need those things?
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Unread 09-01-2009, 08:25 PM   #7
cj847
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The first thing I advise on this kind of situation is DO NOT just randomly throw money at it. I would never repair a P420 or P430 without turning the CEL off several times and making sure I got the code to come back again consistently. Anything you do to try to fix this issue will be very expensive and it could seriously just be a bad tank of gas. Also, be sure that it is not still covered under your warranty. Some emmission items are covered for 100k or more miles.

First your trouble code:
OBD-II Trouble Code: P0420 Catalyst System Efficiency Below Threshold (Bank 1)

If you're gettting a P420 that tells you one thing; if you're getting a p430 that's telling you something else; if you get them both at the same time that gives you other hints.

My daughter recently had a P420 and P430 on her Nissan. After turning it off 3 times it has been trouble free for over 6 months and I never replaced anything. Good luck!
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Unread 09-01-2009, 08:40 PM   #8
valacech
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Thanks for the advice. The only thing is the rattling underneath the car. Those two together have pretty much convinced me that its the cat. Thoughts?
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Unread 10-14-2009, 08:06 AM   #9
jacobfudgepops
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mine rattles like crazy, i need to either replace it, or just cut it off, anybody ever cut there cat off and just straight piped it with a flowmaster 40??
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Unread 10-14-2009, 08:51 AM   #10
LDO
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Check with the dealer before spending the money!! Mine rattles too and I''m getting it replaced under the emission warranty. 2004 with 36K miles. They need the VIN and miles to check and it only takes a minute to see if it is under the emission warranty.
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Unread 01-01-2011, 12:29 PM   #11
mirra9112
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I drive a 99 Wrangler with an aftermarket exhaust manifold, a Magnaflow direct fit catalytic converter, and a Banks Monster cat back. The exhaust system has been installed since July without a problem.

Two weeks ago I found a P0420 code. My friend reset it and it stayed off for a week or so until it came back on.

There is also a loud rattle that is coming from under the Jeep. I really don't want to replace the catalytic converter when this one is just five months old. Any ideas of where to begin?

Last edited by mirra9112; 01-02-2011 at 06:29 AM..
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Unread 02-17-2011, 01:02 PM   #12
TBoons
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My 04 with 50k on it is throwing the cat. CEL and I have been denied warranty work due to abuse. Bone stock TJ. They state it's been up to the windshield in water. I even have a case open with corp. they are no help.

Gotta pick up the Jeep todray from them.
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