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P0401 error code.

Discussion in 'A3/S3/Sportback (8P Chassis)' started by kettle, Sep 14, 2009.

  1. kettle
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    kettle Member

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    [Sep 14, 2009]
    guys had error code
    p0401 Exhaust Gas Recirculation Flow Insufficient Detected

    anyone had this what was the outcome, i changed the egr valve cleared the code but then it came back on the next day.

    could it be the o2 sensor?

    any help appreciated

    steve
    #1
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  3. abpostelnicu
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    abpostelnicu ANdi

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    [Sep 14, 2009]
    Hope this helps:

    Causes
    A code P0401 most likely means one or more of the following has happened:

    The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
    There is a blockage in the EGR (tube), most likely carbon buildup
    The EGR valve is faulty
    The EGR valve may not be opening due to a lack of vaccuum


    Possible Solutions
    In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

    Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
    Clean out the EGR valve and/or tubing to remove deposits
    Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
    Replace the DPFE sensor (with a good quality / OEM one)
    Replace the EGR valve
    #2
  4. kettle
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    kettle Member

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    [Sep 14, 2009]
    ok brill, cheers for the help
    #3
  5. kettle
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    kettle Member

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    [Sep 14, 2009]
    had a long search on the internet, does anyone know the part number for a DPFE sensor?
    #4
  6. abpostelnicu
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    abpostelnicu ANdi

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    [Sep 14, 2009]
    give the vin number and i will look in etka later this day
    #5
  7. kettle
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    kettle Member

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    [Sep 14, 2009]
    just got off the phone to audi parts and they say that part is not listed for my car, which is a 2.0tdi bkd.
    #6
  8. vierx2007
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    vierx2007 New Member

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    [Oct 29, 2009]
    Hey bud,

    thanks for the detailed info but I really had a hard time in finding the ERG valve in my Audi A4 2.8T 98. Do you have idea where it is located?

    thanks.

    #7

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