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P0420 Cat efficiency code

  #1  
Old 07-07-2007, 06:24 PM
mamesA4's Avatar
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Join Date: May 2007
Posts: 4
Default P0420 Cat efficiency code

Did a search, but I have a few more questions.
2002 A4 1.8T w/ 85000 mi. CEL w/P0420 code. Canged both O2 sensors andCEL returns.
Good driveablity, good power, good mileage and no sulfur smell. So how does a cat go bad on a car thats running well? Will a pressure gauge in the before port show more than a couple of pounds due to restriction? I just want to make sure it's the cat.
I checked with Audi and they cover the cat only up to 80,000 mi.
I believe it's a CA car now in NH. Will an aftermarket cat solve the problem or will only OE work?
And lastly, with such a price difference between non-OE cats ($250-$450), is any one better than another?
 
  #2  
Old 07-08-2007, 02:47 AM
auditech79's Avatar
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Join Date: Feb 2007
Location: Nor Cal
Posts: 9,004
Default RE: P0420 Cat efficiency code

Its the cat converter, changing the O2 sensors won't help.
You can get a universal cat converter and have it welded in if you wanna save some money.
 
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