wiring or if the vaccume isnt hooked up it will throw the code to. check the vaccume diagram. the EGR code wotn make your car run in limp mode or anything, it realyl dosnt do crap. people who put skunk2 intake mani. on their cars that are still OBD2 just leave it off and it will throw it, or they just plug it up and let it hang so there wont be a CEL.