the code you're seeing is not a failed egr, rather the pintle is open when it has been commanded closed. while this could be from contaminants, but also there are a few other things to look at... the egr pintle position could need to be relearned... (involves clearing the code, immediatlely disconnecting power and egr, plugging egr back in and turning on car... have the instructions here somewhere if needed0
the other thing? your gas cap.
yep.
i an egr code (it was either this one, or the exact oposite, the pintle was closed when commanded open) and i replaced the gas cap... problem went away, and hasnt come back in months and months