i got a p0401 code, and my check engine light is on.how do i fix this problem?

in your case its usually not the egr valve itself.check for restrictions in the piping heading to the egr valve.

I had the same problem.... But After driving with the ECT PWR button on the dash, the check engine light disappeared after about 100 miles or so (maybe a little more) and never showed again. It may not be a guaranteed solution for your car but certainly a possibility if you have this ECT PWR button.