SES Light - HELP!!!
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
TECH Enthusiast
Joined: Jan 2002
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Re: SES Light - HELP!!! Looks like PO420 is catalyst sytem low efficiency bank 1. Looks like its telling you the CAT capabilties on that side have degraded. Or possible 02 sensor failure or problem. Is it a hard fail...meaning did you try to restse the code and it comes right back? Sais here the light shoud go out in three consecutive start cycles if the problem is no longer there. If it is Id say rear O2 sensor on the left side OR the cat itself is toast. Of course if you haveno cats it means you need 02 sims. Atleast at a quick first glance thats what I get from it. Sorry I didnt have more time...GTG!
Re: SES Light - HELP!!! Thanks for the help guys. 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 your time and help.
