How to test the (DPFE) and (EGV) solnoid

1998 mercury mystique 2.5, V6 and where is the manifold port that needs to be clean out. Do I have to remove the manifold. I can't find a diagram for this cars egr route any where, I would like to know what it looks like so I can do tests from A to B. In other words, where do the hoses come from that attach to DPFE and soforth. When this gets all figured out, how do I rest, so the check engine light won't come back on. I'm getting P0401 code so I wont to go through everything and make sure my (DPFE) and (EGV) soleniod are good also. I know how to check egr valve. THANKS AGAIN!