1999 Pontiac Grand Prix trouble code P0420

Tiny
NKANE
  • MEMBER
  • 1999 PONTIAC GRAND PRIX
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 144,256 MILES
Hi. Well my question is the code p0420, what would cause this code to show up. I have went through and checked for vaccum leaks and everything else I could think of. Please send me any information that you can think of that might help me figure this out. Thanks very much nathan kane
i do apologize its got a 3.8 v6 sorry about that.
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Sunday, July 19th, 2009 AT 6:57 PM

3 Replies

Tiny
BUDDYCRAIGG
  • EXPERT
Need to know what V6 engine you have.

The primary cause is a problem with the converter, but there are other things to look at too.
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Sunday, July 19th, 2009 AT 8:10 PM
Tiny
NKANE
  • MEMBER
Its a 3.8 v6.
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Sunday, July 19th, 2009 AT 8:37 PM
Tiny
BUDDYCRAIGG
  • EXPERT
I have sent you a word document to your email account.
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Sunday, July 19th, 2009 AT 9:30 PM

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