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P0420 Code Replacement

33K views 27 replies 13 participants last post by  thatsgr8 
#1 · (Edited)
So the old p0420 code is on and the dealer has quoted me $1050 to replace the cat. All of the muffler shops are saying about 800. Last nite I ordered up a new cat from auto parts warehouse for $226 delivered. Looks like my sat. will be with the wrenches. I think the hardest part will be clearing the code. Unless the new cat will make it go away
 
#2 ·
Before I had a scanner I would just have the Auto Zone guys do it for me for free. I know their not technically suppose to do it but most of them in my experience don't have a problem doing it.

Update on how much time it takes and what truly needs to be removed to complete. Got to help a buddy with the same thing in a couple of weeks.
 
#7 ·
My part wont be here till Fri. every nite before i go to bed i hit the bolts with some creep/PB Blaster I will do this every nite till I am ready to wrench. This has worked for me before. You just have to deal w/the smell for a few days
 
#4 ·
mine's throwing the same code. which catcon did u get from auto parts warehouse? and it's the passenger side that needed to be changed right?
 
#9 ·
well as I posted last nite the cat was ordered. Sunday I decided to pour 1/2 can of seafoam in the tank w/1/4 tank of gas I drove for about 50 miles before topping it up to full. Drove to work yesterday and today with the SES light on and would you believe the damn light went out when I cranked it up for the ride home. 100 miles and It is still off. I poured the rest of the can in after 285 miles and filled it up again. why could this not have happened before I spent 225 on a cat?
 
#10 ·
^^it will come back... the below the light is just coming on now because the cat is beginning to go. I can do the same with a bottle of techtron. give it a couple of thousand miles. The trigger for that particular code happens when the system sees the same issue twice in a row on two drive cycles. you can figure a normal drive cycle to be a tank of gas. When it gets really bad, the code will just come back on immediately. I drove for almost a year on my drivers side cat (i would not suggest that) but in the end, it was back on within 80 miles or so. Mine is also just beginning to go because the light will come on randomly between 1000 and 4000 miles.
 
#13 ·
Well said I would take pic's and do a how to. I was half way into the job and remembered that I said I would do that. Oh well, it was a pretty simple job. Pulled the inner fender plastic and snapped the bolts off on the exhaust manifold heat shroud. No big deal had to unbolt the exhaust hanger and the rear half of the exhaust for play to get the old cat out and the new cat in. The whole job took me about 2 1/2 hrs start to finish. This is a $900 savings over the dealer. The whole time I kept saying to myself "I'm saving 900" . The rotten egg smell is gone along with the SES light. The box the new cat came in has a return shipper lable to send the old back for a refund. I will get it in the mail this wk. and will post up the refund amount when I recieve it.
 
#16 · (Edited)
^better than nothing.. and u saved 900!! haha. and dude, which cat is exactly?? can u take a pic of it or describe the location.. thanks. i've been meaning to replace mine. definitely on spring break. i found this in rockauto.com:
WALKER Part # 16399 More Information About this Part Ultra Direct Fit Ultra Converter; Right Rear; Fed. & Calif. Emiss. Models
is this the same thing as yours??
 
#17 ·
I know this is a super old thread, but does anyone have a more in-depth guide for this replacement?

I've tried finding some youtube videos but haven't had any luck.

I've got my part ready to go and I'm ready to remove the tire and inner wheel well thingy but I'm a little unclear on procedure once I get in there...

Any help would be appreciated
 
#20 ·
Seafoam, eh? That is likely the explanation as to why your Cat failed.
 
#24 ·
Here is what I did recently to "fix" the P0420 code (oxygen sensor spacer from Amazon).

AZ-Ted I am in Avondale. Did the spacer fix the P0420 code or did you eventually replace the passenger side cat? I had my driver side replaced yesterday and on a drive last night the SES light came on. O'Reilly scanned it and it was the P0420 code. I thought about doing the spacer, but that seems to be a bandaid fix. Advise from others on this mod would be great.
 
#27 ·
Not trying to be a flamer, but since the cats on the X are all flanged and bolted, cutting and welding sounds like a hack job to me. I would think that could be nothing but trouble down the road. Replacement of the original really isn't that hard if its not spent its entire life in salted winter roads.
 
#28 ·
The cat was cut out in the middle of the two flanges and welded in. So down the road I will still be able to change out with a direct replacement. I live in Phoenix Az. we do not worry about road salt, it never snows here. I know it is not hard to replace them, but I didn't feel like messing with it. To much on my plate to dive into that right now. Your comment "Flamer" was funny. Of course I took it the way it's sounds. Hahaha.
 
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