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2011 with P0401 driving me crazy

Discussion in 'Gen 3 Prius Main Forum' started by Steelerfan2018, Aug 1, 2022.

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  1. Steelerfan2018

    Steelerfan2018 Member

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    Hi all,
    2011 prius with 150k miles. A history of P0401 errors. Car also uses about a qt of oil between changes. Otherwise the car runs well.

    I now have something like $1500 spent in solving P0401. I have had the following done: new spark plugs, EGR cleaned, EGR cooler cleaned, PCV valve changed, MAP sensor cleaned. It has run a few months without errors, but it is now back again - the problem this time is that I am short on funds and it may be a while before I can have it worked on again.

    - if anyone out there has had this error, how long can you drive with it?
    - is there anything I can do to keep it running OK before I can put it in the shop?

    Thanks,
    Rob
     
    #1 Steelerfan2018, Aug 1, 2022
  2. PriusCamper

    PriusCamper Senior Member

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    Have you added an oil catch can yet? Perhaps adding that and cleaning EGR, the pipe and the cooler again will put this problem behind you for good?
     
    #2 PriusCamper, Aug 1, 2022
    Last edited: Aug 2, 2022
  3. nate358

    nate358 Junior Member

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    Oil catch can does not go into the Egr system... It goes after the PCV valve before going back into the intake manifold.

    Posted via the PriusChat mobile app.
     
    #3 nate358, Aug 2, 2022
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    Maybe the egr valve has failed shut. Other reasons such as a clogged egr cooler and a bad map sensor seem to be covered.
     
    #4 rjparker, Aug 2, 2022
  5. PriusCamper

    PriusCamper Senior Member

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    Oops... Just edited that part. Thanks!
     
    #5 PriusCamper, Aug 2, 2022
  6. ChapmanF

    ChapmanF Senior Member

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    I didn't see any mention of the intake manifold being cleaned. Its four small EGR passages are part of the total EGR path, and any occlusion there can cause your EGR insufficient flow code just as easily as occlusion anyplace else.

    The manifold is easy to remove for cleaning.
     
    #6 ChapmanF, Aug 2, 2022
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  7. Steelerfan2018

    Steelerfan2018 Member

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    Hi all, thanks for the replies.

    Q - I am thinking of trading it in on a 2013. Did they fix the oil burning issue by 2013?

    Thanks,
    Rob
     
    #7 Steelerfan2018, Aug 4, 2022
  8. PriusCamper

    PriusCamper Senior Member

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    #8 PriusCamper, Aug 4, 2022
  9. rjparker

    rjparker Tu Humilde Sirviente

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    No almost exactly the same. In 2014 mid production they used better pistons and rings.

    Compare last six digits.
    Prius 2014 Vin Production Change.jpg
    Most likely your egr valve is no longer opening or you have a completely clogged intake as suggested above. If you want to go down the clean intake rabbit hole, here is a good video.



    His approach "apparently" cleared the morning stumble and mid range operation. Until you read the comments where he bit the bullet a few months later and rebuilt the engine because of oil burning and the resulting head gasket fail.

    Which is why most dealers and many pro mechanics rebuild rather than do a simple head gasket. Nevertheless, the video is clear and concise.
     
    #9 rjparker, Aug 4, 2022
  10. KamiKKazi

    KamiKKazi Member

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    If you can get a cheap pressure washer and pressure wash the intake it will clean out the EGR passage. Once you overcome this issue your car will run a lot better, I wouldn’t sell your car just because of this issue. You could even buy a new clean intake if your egr pipe and egr cooler are still clean that would fix your issue
     
    #10 KamiKKazi, Aug 4, 2022
  11. Steelerfan2018

    Steelerfan2018 Member

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    Crazy update - the engine light went away on its own.

    I also looked up the value of my 2011 and it has gone up $2500 since I bought the car last year. Seriously thinking of trading it in while the value is this high.

    Thanks all,
    Rob
     
    #11 Steelerfan2018, Aug 5, 2022
  12. bettergolf

    bettergolf Active Member

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    It's a break even or less transaction on that valuation trading it in...the value of whatever you buy is also inflated....probably more than your prius. If that's what you wanted to do anyway, by all means do it, but if you think you're getting ahead on it...well....most likely not.
     
    #12 bettergolf, Aug 5, 2022
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