CEL code P0401 fixed

Hi all, thought I would share this in case it helps anyone else. I was getting a check engine light with trouble code P0401 (EGR Flow Insufficient) and tried cleaning the EGR and also the passageways from the top. I tried spray, blowing out with shop air and even affixed a .38 cal brass gun brush to the end of a length of nylon tubing (wire tied it on to be sure) and tried to clean the passageways that way. It seemed to work well on the rear passage (going to exhaust) but couldn't make the bent to clean the intake passage. Also, I found that there was a slight intake manifold leak by spraying carb & choke cleaner around the joints of the intake. I decided to pull the upper and lower manifolds and reseal them with new gaskets. Once apart I found ALOT of oil and carbon deposits inside including ON the gasket surfaces which showed they were leaking. While cleaning it I also found the inside EGR tube which runs the length of the manifold was almost completely clogged with carbon. Looking at it I realized if anyone else has just the EGR low flow issue they could clean it out from the outside, just by removing the throttle bore (it can be seen in the pic at the bottom of the opening). You should be able to remove this and the EGR and use a gun brush or similar to clear the obstruction then vacuum out the mess. I had to remove everything anyway due to the manifold leaks but otherwise this would have been a much simpler fix! Attached is a link to a pic of what i am talking about. Hope this helps some of you! Steve
http://www.vehicross.info/gallery/da...manifold-r.jpg

Nice photo. I learned something.

Good stuff

Thanks for the post!!

A PERFECT illustration why I HATE EGR system! I guess I have an extra task to do when I am replacing my thermostat :)

This would probably explain why on certain angles it comes on 100% of the time, since its probably a hardened deposit that rolls around and blocks it at one angle then lies at another angle and allows it to pass.