02 Grand Am P0420 OBD-II Code

[drebond007]

I know that this code usually means your catalytic converter is operating below the specified efficiency threshold. I also understand that it can originate from a malfunctioning 02 sensor. I do not have much repair experience but I kind of want to get an idea of the likelihood that the code means I need to replace my Cat before I take it to the repair shop. I was under the impression that the life of a Cat was much longer than 6 years and approx. 75K miles. Thanks for your help in advance.

[xeroinfinity]

Welcome to AF.

I would test your O2 sensors before even considering replacing the converter. Thier is a test procedure in the Tips and Maintenance subforum.

Also the converters are covered up to 100-110k miles, the warrantys were extended.

[drebond007]

Today I took my car to the Pontiac dealership and they uncovered that the catalytic converter was in fact bad. The catalytic converter on the 2002 Grand Am is warrantied for 80,000 miles/8 years so fortunately my car fell just under the threshold with 75,000 miles. The dealership ordered the converter for me and are going to replace it on Wednesday. Thanks for your help.

[xeroinfinity]

That sucks about the warranty! I could hav swore they extended it on converters. 2002's must have flaky Cats because thier sure are a lot of them going bad early.

[crazy Jim]

converter on my 02 trans am went bad at 65K, from what I understand it is quite common