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Check engine codes P-401 & P-402

Discussion in 'Under the Hood' started by gss, December 22, 2004.

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    1. gss

      gss Member

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      City, State:
      Bellinghm, WA
      Year, Model & Trim Level:
      1997 XLT
      I have had the check engine light coming and going for 2-3 months now. Finally got into Schucks and hooked up the scanner and got P-401 & P-402 codes.
      I did a search and read the articles and Glacier991 primers.
      On the way back home the light went off. Where do I go from here since you say it may not be the EGR. P-401 says Restricted EGR Flow--- P-402 EGR- Excessive flow detected. I am lost at this point.
      Engine seems to run just fine.
      How about a SeaFoam treatment? I use it on my Mercury 200 HP outboard, will it clean out things on this engine?
      Help?????
       
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    3. 97BlackX5.0

      97BlackX5.0 Active Member

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      Year, Model & Trim Level:
      97 X XLT AWD
      do a search for dpfe sensor.... its most likely that this is clogged or broke.... in otherwords your egr is working fine but the sensor that senses whether it works find or not is either clogged or the plastic pos broke.... if you have the 4.0 its usually over by the ps pum and intake... kinda between the two.... on the 5.0 its between the firewall and the intake manifold.... its mounted to the intake manifold.... there should by two hoses going into it and a plug...in either case.... i had to replace mine and i believe those were the codes i had.... it was about a 50 dollar part.... and if you can find it you can change it and then unhook your battery to reset the computer... let me know how it goes.
       
    4. Eneurb

      Eneurb Active Member

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      If the scan tool that you are using to pull the codes will actually let you look at the dpfe voltage, it should be at around 0.6v key on engine off... anything too far off of that will give you a code. Also check that the hoses are not too deteriorated and make sure not to switch them up if you are replacing the sensor.
       
    5. gss

      gss Member

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      City, State:
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      Ok, I found it and located the part from NAPA for about $50, depending on tax. I will get it ordered after the holidays. Looks real simple and the light is still out.
       

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