My CEL has been glowing for over a year at least... finally got the code pulled and got a P0401 & P0420. The mechanic that pulled the codes told me it needed a new EGR valve and to clean out the carbon, etc. Pardon my ignorance, because I know very little about cars, but I just noticed that the EGR vacuum hose has apparently melted or been rubbed raw and it is broken in two. Could this be enough to throw the CEL's?
