01 T&C P-0455 Code Help

I have a new cap. And can not hear or see anything leaking or broken. I had the code erased but it stayed on, or came right back on. I hear from other threads that a smoke test can be done, is this something I can do? Is there anything I can do myself to try to find out what is causing this? Above the alternator is something that goes into the egr valve, it kinda looks like the egr valve but has an electrical connecter to it, is that for the egr or is that the vacuum flow sensor that could be causing this code? Tools I'd need? Any help would be great. Thanks

Might help: http://www.obd-codes.com/forums/1960-obd-codes-2001-dodge-caravan-with-trouble-code-p0455.html