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Still P0401 after cleaning egr !! should we drive it?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ozmatt, Mar 27, 2021.

  1. wheezyglider

    wheezyglider Active Member

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    Even though it isn't proven that the problem is the valve, if you really want to buy one I'll tell you a dirty secret. For some reason it's cheaper to buy the valve and gasket set together than it is to buy the valve alone. The part number for the set is: 04004-58137. I took a peek at ebay.com.au and there are listings that ship from the US for under $300 AU.

    I don't know why the set is cheaper. I was worried it was because maybe they include the oldest revision valve, but the photos always show the later one.
     
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  2. ozmatt

    ozmatt Active Member

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    Hey Wheezy :)

    Yeah I noticed the set on ebay.com with gaskets via that part number you mentioned .. figured maybe not oem.. or old stock

    However searching eBay.com.au yield fewer results as most of the cheaper sellers do not ship to Australia, cheapest here is about $330/350 which is still okay (if it's the problem) better than $660 for a used valve from local rogue yards

    Will hold out on a brand new valve for a few days in hope a kind pc member out there with four spares in their cupboard chimes in :) I can see good used valves are cheap common and plentiful outside au

    Posted via the PriusChat mobile app.
     
  3. ChapmanF

    ChapmanF Senior Member

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    I wouldn't even mind just knowing the difference between the earlier Gen 3 valve and the later one that needed the wire harness untaped to reach.
     
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  4. ozmatt

    ozmatt Active Member

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    Not to second guess my own work but to save me having to pull the thing off again for no good reason! can anyone please confirm if a blocked or cracked intake manifold alone can trigger P0401

    Chapman I wondered the same for the late 3rd gen valve, opens my horizons

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  5. ChapmanF

    ChapmanF Senior Member

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    If the EGR gallery in the manifold is blocked it sure could.
     
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  6. AW82

    AW82 Member

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    My neighbors is correct hand drive. I'll ask him to prove it to me!
     
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  7. ozmatt

    ozmatt Active Member

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    Thanks Chapman, considering checking it incase some crud was lodged somewhere and showed it's head after install, really doubt it though as I cleaned each tiny orifice with a purpose bought brass brush egr cleaning kit and soaked and flushed it before & after, and oven cleaner, it was flowing clean water out each hole by the time I was done so really doubtful

    I thought most people were not getting this code until everything including the cooler is completely plugged

    Meh stupid cars lol grumble grumble

    Will get there in the end, always do!!

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  8. ozmatt

    ozmatt Active Member

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    Actually i will cheat and just remove the egr pipe and punch some compressed air through the manifold
     
  9. Raytheeagle

    Raytheeagle Senior Member

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    That was first go round:cool:.

    And was definitely the last go round with that method:whistle:.

    For some other parts of the discussion, I leave the lower stud on as a mounting point but remove the nut as that is NOT needed;).

    Unless you like to contort your hands:).

    My lower egr cooler nut collection is at 11 by the way, so I need my toes to start counting with appendages (y).
     
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  10. ozmatt

    ozmatt Active Member

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    Hi Raytheeagle

    I too left the lower stud on as a support prop and the nut in my junk box, I do not wish to ever get anywhere near your spare nut count lol

    may I ask, do you know if a faulty stepper motor or valve exhibits similar symptoms to a blocked system, I mean having to ramp to around step 25 to make engine stutter?

    Cheers :)

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  11. Raytheeagle

    Raytheeagle Senior Member

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    If the system is not functioning properly, it can;).

    Use an impact screwdriver and open up the system to get a lay of the land:).

    I've seen rusty components in there before so that isn't good:cool:.

    But opening it up and snapping some shots can help those not with you to assist (y).
     
  12. AW82

    AW82 Member

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    @Raytheeagle since you're here and we're counting your nuts....:eek:

    Is removal of the studs for the exhaust manifold connection really necessary? The diagrams I see make it look like it isn't if you remove the side studs.
     
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  13. ozmatt

    ozmatt Active Member

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    its spotlessly clean in there, i had it off for cleaning the valve seat, to my surprise my egr system cooler and valve/ pipe work was never really very blocked, a little dirty but not "blocked" .. the manifold was the worse part of my system so i always had a bad feeling cleaning was not going to help!

    I will take some shots very shortly .. stay tuned! & thankyou very kindly :)
     
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  14. Raytheeagle

    Raytheeagle Senior Member

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    Some studs have to come off;).

    Which ones are personal preference :).

    I do remove the rear cooler studs from the exhaust manifold connection because it makes the reassembly less frustrating(y).
     
  15. ozmatt

    ozmatt Active Member

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    Here's some pictures,

    note when first removing the stator or cap what ever its called, the magnet unwound it's self around two turns (to the position shown in my last photo) just enough to reveal the lower bearing..

    Manually wind rotor back down, it "self unwinds" about two turns to same position mentioned above

    note some small pieces of plastic or magnet material populating the inside of rotor..

    Is it normal to have the little stepped up piece of plastic at the base of the thread in rotor, the piece that seems to get progressively steeper but it's only around 3mm long .. 12 o'clock on my first & third photos on the inside surface of rotor

    Note top bearing can slide up and down on its perch a smidgen, maybe 1mm

    Note!!! Rotor feels a like it has perhaps excessive play aka side to side movement on the thread it's "worming" on

    Note sorry if I don't explain things properly, I do my best! Lol IMG_20210401_153154_311.jpeg IMG_20210401_153131_569.jpeg IMG_20210401_152642_685.jpeg IMG_20210401_152134_491.jpeg IMG_20210401_152332_576.jpeg IMG_20210401_151519_884.jpeg IMG_20210401_151454_945.jpeg

    Posted via the PriusChat mobile app.
     
    #55 ozmatt, Apr 1, 2021
    Last edited: Apr 1, 2021
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  16. ASRDogman

    ASRDogman Senior Member

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    Nifty! Thanks!
     
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  17. ozmatt

    ozmatt Active Member

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    the more i look at it the more suspicious i am of that little plastic dick in the bottom of the rotor that i mentioned earlier looked like it was progressively sloped on one end, i dont think its supposed to be sloped! i am guessing its some sort of rotor position sensor as such that works via the little metal dimple on valve, looks like the dimple on the valve has been slipping past (and straight over the top) of the plastic dick!! presumably started due to the plastic thread inside rotor being flogged therefor rotor not running true lol :)

    edit! .. maybe it is supposed to be sloped, however i doubt its supposed to have a slot scribed through the middle of it that corresponds perfectly with the dimple on valve, if you know what i mean, sorry i can not get better photos my phones about as good a as my car right now!

    also noticed if i look down the rotor thread with one eye shut (looking from end closest to top bearing) the thread looks flat and flared out much wider (flogged) at the top than the bottom, slightly cone shaped if you will ..i hope that makes sense? sorry i cant explain better
     
    #57 ozmatt, Apr 1, 2021
    Last edited: Apr 1, 2021
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  18. ChapmanF

    ChapmanF Senior Member

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    Yes, it's a simple mechanical stop, nothing more. When the rotor is stepping in the "closing" direction, and that ski jump hits the metal stop, that's where "closed" is.

    Well, that'd do it then. Remember the ECM doesn't bother trying to learn where "closed" is, it just (according to the manual) keeps trying to step the motor in the "closing" direction forever, whenever it doesn't want the valve open. If the mechanical stop is chewed up, of course the thing is going to step a bunch of extra steps past "closed" until the rotor finally bottoms out, and then it'll have those extra steps to cover again when opening before it really starts to open.

    I wonder if that's really the "the motors go bad" situation that some other post was alluding to.

    At least we know the problem isn't insufficient stepping torque! :eek:

    MacGyver with a plastic welding kit or some epoxy might just build the ski jump back up, only it looks like the access isn't great. (Before you laugh, I did fix a friend's washing machine timer that way once.)

    Unmasticated ski jump:

    stop.jpg
     
    #58 ChapmanF, Apr 1, 2021
    Last edited: Apr 1, 2021
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  19. ozmatt

    ozmatt Active Member

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    ChapmanF thanks for the photo of your ski jump lol :) .. been trying to get a look at one of these all day! We may have put this to bed, I mean I won't call it early but it's not looking good for that rotor, it's clearly damaged compared to yours.

    I was thinking the same way as you, hit it with the soldering iron or some epoxy just for an experiment, I doubt it will last more than a few hours or days because Im pretty sure this starts with a flogged thread so the rotor starts to worm up/down unevenly

    Thanks again, you guys rock!

    Now, who has a spare rotor to sell me lol .... :)

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  20. Mendel Leisk

    Mendel Leisk Senior Member

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