Computer problem
2006 Buick La Crosse 6 cyl Front Wheel Drive Automatic 38000 miles
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The check engine light came on and the error code read P0411. I reset the code and the next day the error code was back. The car runs good with no noticeable performance issues. I have not found any vacuum hose leaks but I wasn't sure what I was looking for. I'm not sure what to look for and/or test next.

you have to see if the air pump is working first,you have to use a scan tool that can command the air pump on/off to see if it works.a code like this is hard to answer,it code be a number of things,from a blown fuse to a bad relay or a bad air pump,even a blocked hose to the air pump.