Code P0401 Problems.

Discussion in '1st Gen - 1997 - 2002' started by Extortion, Jul 10, 2012.

  1. Extortion

    Extortion Active Member

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    Just bought a 1999 Expedition XLT 4.6L & noticed the trouble code P0401.. It Runs Pretty Rough Driving (lots of vibrations) & also has a kind of ticking around the engine.. Would this code do any of those symptoms? What's the best way to get started on fixing this code as well? Thanks in advance!
     
  2. rburch

    rburch Full Access Members

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    OBD-II Trouble Code: P0401 Insufficient EGR Flow

    You should start off by taking off the throttle body elbow and cleaning it making sure to pay attention to the egr passages. This is a known problem with carbon clogging up those passages.

    Work from the bottom up on the causes list in the link!
     
  3. Extortion

    Extortion Active Member

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    Any good tips on taking the Throttle body off and cleaning it? I never done this before & researching it hasn't given me much
     
    Last edited: Jul 10, 2012
  4. rburch

    rburch Full Access Members

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    Its fairly simple. there 3 bolts that hold the TB cover on and i believe 4 bolts on the intake elbow. Its easy to drop the bolts down under the intake manifold so be careful!

    Use some carb cleaner to loosen the carbon and a screwdriver may be needed to loosen the carbon in the egr passages. inspect the EGR valve for carbon build up, if any claen it with the carb cleaner. Once you get it cleaned up put it back together and diconnect the neg battery cable for a couple of min to erase the codes and reset the computer. Start the truck and let it run at idle for 15 min to relaern air/fuel and idle speed etc. Let it get up to operating temp and take it for a test drive in city and hwy driving for 20-30 min. Drive it kind of aggressively to see if you get CEL. If the CEL doesnt come back your problem should be fixed!

    Check back when finished!
     
  5. Extortion

    Extortion Active Member

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    Thanks!!! I will give it a go tomorrow.. been raining all day here in FL
     
  6. Extortion

    Extortion Active Member

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    Just a quick question but how does this code make your truck run? I'm trying to figure put if my problems are due to this code.. obd2 only shows this code by the way. my truck runs like shit to say the least and i wanna make sure it's not the transmission going out on it. by any chance wouldnt a code be thrown for any trans issues?
     
  7. cyoung

    cyoung New Member

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    You need to replace the DPFE module. Do a search on this forum to get more details. I just went through the same thing with my 2000 Expy and the $53 part fixed me up. Clean your TB also, it can't hurt.
     
  8. cyoung

    cyoung New Member

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    I keep getting the P0401 code on and off every few weeks even after changing out the DPFE module. I cleaned the throttle body today and the CEL went off as soon as I put everything back together and started the truck. It only took about 30 minutes to remove and clean it and it was covered in black soot. I did not have to reset the battery to get the CEL to go off.
     
  9. Exia

    Exia Full Access Members

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    Try this site it even gives a video

    OBD II Code P0401 (Ford)

    I had the same issue when I first bought mine after changing out the DPFE, hoses, EGR Valve, & O2 sensor. Come to find out it was a Coil going bad. Once I replaced plugs and coils no more vibrations
     
    Last edited: Aug 11, 2012

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