What does this code mean???

Hey everyone
Just got the car scanned and need to know what this codes means
406 EGR valve malfunction????
Please let me know so that i can correct the problem.
Thanks and Godbless

P.S.
3.8l 94 Buick Lesabre Custom 200,000 + and rollin

My sister used to live in Longwood, now in Orlando. Anyway, this refers to the egr pintle position, either it is carboned up or just defective, remove the egr clean up the pintle and seat, see what happens.