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SES Light - HELP!!!

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Old Jan 13, 2003 | 04:00 PM
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Default SES Light - HELP!!!

I had a friend with a snap on scanner see what the light was on for. It gives me a code of P0420. Anyone know what this code is for. Also I just installed the NOS noszle system about a week and a half before the light came on. ANY help would be appreciated. Thanks
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Old Jan 13, 2003 | 04:04 PM
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Default Re: SES Light - HELP!!!

Catalyst System Low Efficiency

try posting in diagnostics or if you're patient, wilwaxu for move it for you. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Old Jan 13, 2003 | 07:55 PM
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Default Re: SES Light - HELP!!!

Thanks for the help. Do you think it could have been caused by anything I did under hood while I was installing the NOS kit, or spark plugs. Also I had the code cleared and it came on again after about 50mi. Thanks for you time and help.
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Old Jan 13, 2003 | 08:41 PM
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Default Re: SES Light - HELP!!!

from my limited experience, it sounds like a rear O2 prob to me. do you have headers or 02 sims? i'm not really up to speed on NOS, but if you search that forum for effects on catalyst system, it might bring something up.

FYI, for future codes, there is a code translator on this page. big bright red box at top left. good luck with your code.

btw, if it is a rear 02 code, it's not fatal, and i'd lay off the spray until you can get some better clarification.
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Old Jan 13, 2003 | 10:01 PM
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Default Re: SES Light - HELP!!!

My whole exhaust systme is stock w/ the CME's. I'll check my O2's ASAP. Thanks again for the help.
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