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P0401—--Cleaning clogged EGR passage—--Pictures that I hope will help others…...

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  • P0401—--Cleaning clogged EGR passage—--Pictures that I hope will help others…...

    I'm posting this, at this point, not to ask for any help, but to provide some information to help other.

    My Contour had been intermittently throwing P0401, and I had a memory from long ago of reading that the Duratech is prone to carbon deposits clogging the EGR passages, leading to this fault.

    I was assuming that it was probably the main tube, that goes from the EGR valve down into the mysterious wilderness behind the engine, presumably to some part of the exhaust system; and anticipated that I would probably need to remove the EGR valve and clean this tube.

    Fortunately, I thought to do a bit of Googling first, whereupon I learned that the issue actually occurs most commonly somewhere around the throttle body/intake manifold.

    So, instead of pulling the EGR valve,I pulled the throttle body. The gasket remained sticking to the intake manifold, and I figured I'd just leave it in place, clean what I could, and put the throttle body back.

    Looking at the outside of the intake manifold, I could see a passage leading to the EGR valve, and I made a guess as to where, inside the manifold, to try to direct a piece of wire to try to snake it out.

    After doing that, and feeling somewhat distressed that I hadn't really noticed that I was loosening or removing any debris; an unrelated thought occurred to me that perhaps I should pull the gasket off entirely, and make sure it and the matching surfaces were all clean. I know I should replace the gasket, but I was in a cheapskate mode, and didn't feel like going anywhere anyway. (So great was this mood, that noticing that the air filter was dirty, and ought to be replaced, I instead laboriously washed it, and then set up an arrangement with it and a fan to help it dry.)

    Anyway, it would have saved me some time and effort if, among my Googling with regard to this issue, the pictures below, and the information that I am about to provide had come up. I guess someone who wasn't so much of a cheapskate as to reuse the old gasket would have found this anyway, in a timely manner.

    It turns out that when the throttle body gasket is removed from the intake manifold, the area where this issue occurs is exposed in all its glory. It's this odd little passage, below the main air passage. That is where the EGR comes into the intake, and that is where the carbon deposits occur. It's easy to see why this passage would be prone to such deposits; and I am amazed that my P0401 was as intermittent as it was, as I found this passage to be so thoroughly clogged that I cannot see how any recirculated exhaust gas was able to get through it.
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    1996 Mystique GS, Zetec, ATX — Totaled in a collision on 26 Oct 2009
    1997 Contour “Sport”, Duratec, ATX — Successor to the dead Mystique
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