2005 dodge ram 1500

Yes i hav a 2005 dodge ram 1500 and my check engine light came on and i took it to an auto parts store and i got a cde p0404 is there any one that knows what thsi means and what i can do to fix it and waround how myuch it will cost and is it ok to drive like this . please if someone can help me .

i think it's a egr code