Hello. I am the owner of a 2002 Buick Century Custom. The check engine light was shown about three months ago. I did the OBD2 check and p0420 was the result. What shall I do now that that has come up?</span><br style="font-family: Arial,Helvetica,sans-serif;"><br style="font-family: Arial,Helvetica,sans-serif;">Thank you.</span><br style="font-family: Arial,Helvetica,sans-serif;">

well this might help, not sure http://www.aa1car.com/library/p0420_dtc.htm


Edited by: Rusty

go to autozone and have the code cleared

then see if it comes back on again...

if it does
get a new cat or remove the one that is on there..

my local autozone has stopped clearing codes, said the main office made them, they''ll read them but won''t clear them, unhook your battery for a few mins, then hook it back up, see what happens.

my auto zone lets people take the scanner outside by them self and then all you have to do is press clear.

and it does it.

if you ask the youngest kid in there to help you out
you can tell him to clear it "off the record" and he will..

there parts guys.. not rocket scientists

yeah, but around here the girl who is the store manager is a real stickler for rules, and the others are scared of her.
But back to the code, do check to see if you clear it, by scan tool, or by unhooking batt. see if code comes back.