Having problems with your 2003 Pontiac Grand Am ?
Po420a cuts out then dies
P0420 is a cat innefiiency code. These are covered for 8 years/80 ,000 miles under the federal emissions warranty. If you are our of the warranty than you I'll be footing the bill yourself.\012\012You have a couple of options. Replace it with an O.E. cat from the dealer. Or you can replace it with an aftermarket direct fit fm a reputable manufacturer.\012\012Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!
I would check air filter, if you havent changed it, chances are its plugged, if not air cleaner,most likely MAP sensor, take to autozone, they will do a free diagnostics if you ask them(and if able to drive it there) they can tell you whats wrong by the code they get, it only takes a few min. If you havent changed air filter and your car is used, I would do that first, If you cant see through the filter, when looking twords the sun, its plugged, just bend it slightly to look between folds, most of the time its obvious. make sure when changing air filter, you vaccum out the air filter holder...hope this helps...bernie
Repair Help & Product Troubleshooting for 2003 Pontiac Grand Am
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