1999 GMC Sierra Diag Code P0420

1999 GMC SIERRA
133,000 MILES • V8 • 4WD • AUTOMATIC
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SKELIX912
  • MEMBER
  • 1 POST
i used my programmer to get code P0420 and so i took it to a midas to have them take a look. the guy told me that i needed to replace my cat. converters and that it would cost $1,200 parts and labor. the guy also said that i should replace all 4 o2 sensors. i just moved to az from ca but will eventually end up back in ca so i want to stay ca emissions legal. is that price typical for a cat. converter? are there any other options around replacing the cat. converter?
Jul 16, 2008 at 2:10 PM
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2CARPRO JACK
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 11,533 POSTS
Usually the catalyst efficency codes are pretty accurate. Try clearing the code and driving to see if it comes back. I have seen that code set if the truck is driven really hard, but not come back if driven easy.
Jul 16, 2008 at 3:06 PM