P0400 what to look for?

P0400 Exhaust Gas Recirculation Plow Malfunction , i know these car can only get 2 codes in the 400 range but autozone gave me this generic code. i started getting this after a guy worked on my car to do a valve job. i am trying to figure out if he connected all the vacuum lines where they are supposed to.
https://www.dropbox.com/s/5rz8jlhjby...220_093357.jpg
https://www.dropbox.com/s/huuwazpypa...220_093220.jpg
https://www.dropbox.com/s/t6m0nylohl...220_093145.jpg
https://www.dropbox.com/s/05c9fjmkcm...220_093134.jpg
https://www.dropbox.com/s/pci6arxfyz...220_093117.jpg
I tried cleaning the lines with carb cleaner

on the rear of the plenum you have like an L shape tube with the metal like an accordion on the pass. side. check that to see if its connected correctly. I know when I changed mine I also had to put a gasket on it. That is the exhaust Recirculation.

yes it is on, i think i fixed it. i started the car and started looking around with the car on. after a while like 10 minutes i started to hear a pulsating hissing sound. i looked around and noticed that where the selenoid is, one of the hoses the one with the cilcular thing tha looks like some sort of filter. that hose wasnt sealing correctly. so i took some zip ties and tighten it and the hissing sound stopped. i disconnected battery to erase the code. ill let you know if the light comes back on.