Code P0420

Reply Subscribe

Thread Tools

Search this Thread

07-28-2008, 01:35 PM

rhlow01GT

Thread Starter

Join Date: Jan 2008

Location:

Posts: 37

Code P0420

Anybody ever had code P0420 show up on a code reader and if so, what should I do? I know it has something to do with either the catalytic converter or oxygen sensor on the passenger side but I don't know how to determine which one is it. Any help would be greatly appreciated.

07-28-2008, 03:31 PM

cliffyk

TECH SAVANT

Join Date: Dec 2006

Location: Saint Augustine, FL

Posts: 10,938

RE: Code P0420

Here's what the shop manual says...

07-28-2008, 03:41 PM

mustangman02232

6th Gear Member

Join Date: Dec 2004

Location: Ludlow, Mass

Posts: 15,864

RE: Code P0420

its probably due to your X pipe, a set of MILS will take care of it, or replace the cats

07-28-2008, 05:36 PM

blackGTcp

4th Gear Member

Join Date: Oct 2007

Location: Lafayette, LA

Posts: 1,146

RE: Code P0420

Can this occur even with a catted X? Mine stays on and theres a popping sound coming from the exhaust tip

07-28-2008, 05:59 PM

cliffyk

TECH SAVANT

Join Date: Dec 2006

Location: Saint Augustine, FL

Posts: 10,938

RE: Code P0420

Quote:

ORIGINAL: blackGTcp

Can this occur even with a catted X? Mine stays on and theres a popping sound coming from the exhaust tip

[/align][/align]How old/how many miles on the catted X?[/align][/align]Who made it?[/align]

07-28-2008, 06:10 PM

blackGTcp

4th Gear Member

Join Date: Oct 2007

Location: Lafayette, LA

Posts: 1,146

RE: Code P0420

I couldnt tell you how much the guy I bought if from had put on it but I putabout 8K. Its an SLP

07-28-2008, 09:54 PM

mestit3

2nd Gear Member

Join Date: Feb 2008

Location: lexington, ky

Posts: 336

RE: Code P0420

thats the one that comes on mine for my x pipe

07-29-2008, 01:01 AM

cliffyk

TECH SAVANT

Join Date: Dec 2006

Location: Saint Augustine, FL

Posts: 10,938

RE: Code P0420

Quote:

ORIGINAL: blackGTcp

I couldnt tell you how much the guy I bought if from had put on it but I putabout 8K. Its an SLP

[/align][/align]Then my first thought would be that the bank 1 converter is shot. You need MIL eliminators (make your own for $5), or a tune that disables the rear sensors...[/align]