if you found a code that has to do with the EGR valve then most likely thats the problem. The EGR has a sensor on it that senses valve position, if the valve doesn't move when its supposed to then you'll get a CEL.
I sugest you do what was suggested, remove the throttle body and all the other throttle related stuff to clean the ERG ports in the intake manifold and remove the EGR valve and see if you can clean it as well, this is also a good time to replace the valve.
After everything is clean, reassemble everything with new gaskets to ensure there are no leaks.
