I own a 2007 Lacrosse that I purchased last June with 36K . A few weeks ago the CKL came on. I hooked up my scanner, and it threw code P0401. I pulled the EGR, checked everything and sprayed it full of WD 40. After letting it sit for a couple of hours, I blew it out an reinstalled it. It was fine for about 2 weeks, the the light came on again, P0401. I went through the cleaning process again, same results. The engine runs fine. I am thinking that my only option is to replace the EGR, even though there is no guarantee that will fix the problem. Any suggestions?

You may have to take off the two metal hoses and clean them thoroughly in case those are clogged. Check inside the lower intake manifold passage as well once you have the metal hose off.

What ^^^ he said. All the passages need to be cleared.

You could try cleaning out the flex passages like RedCloud657 ^^^^^^^

. . . but often these just need the valve replaced. Some detailed pictures of the EGR would tell us more, especially of the pintle and seat.

Doesn't look too bad from here, can't see the seat though. That being said, with what I can see it might just be that the EGR valve is getting tired.