# 2001 altima code p0420



## seamustry (Dec 16, 2009)

i went to autozone to get my "check engine" light looked at and they gave code p0420. 

they say cat is bad. 

my question: can rear O2 sensor give code p0420? I talked to a guy at Firestone and he said O2 sensors have a different code...not sure what to do so I came to this forum for your expert help! Muffler shop will change cat for $600.

Thanks for any advice!


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## billyfrazier (Apr 18, 2008)

ok one thing,my 99 gle has a code p420 for 4 years,and ill turn it off with my friends scanner,then ill drive 3 months it comes on again p420,my gas mileage is 23 in city,runs fine,my car even sometimes turns light off itself,but reappears later,if your car runs good,have the light turned off,and see if it comes back on,a blocked cat will causesevere driveability problems!


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