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P261C and P261C* is it inverter or engine water pump?

Discussion in 'Gen 3 Prius Main Forum' started by memento1984, Aug 7, 2017.

  1. memento1984

    memento1984 Junior Member

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    Last week car started overheating after 300 miles, managed to limp back home, 50mph. Thought this was thermostat. Ordered it, today car broke down. Loud swish sound, check engine followed by yellow triangle of death, "check hybrid system". Towed car home, tried resetting the error but it would come back shortly after, when engine idled for 5-10min. Which pump is at fault? Thanks guys!!!
     
  2. memento1984

    memento1984 Junior Member

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    Just to make sure it is pump, are there relays fuses to double check? Thanks again!
     
  3. bisco

    bisco cookie crumbler

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    you can check the inverter pump by looking for movement in the reservoir.
    is it possible that you introduced air into the engine coolant loop?
     
  4. memento1984

    memento1984 Junior Member

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    that is possible. when the car overheated there was 4-5quarts missing at that time (put them back right away, but air might have gone in, no question). how to flush it ?
    would that ruin the pump, or would the ECU throw those errors as result?
    is there any point at looking for the fuse/relay ?
    thanks!!!
     
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  5. bisco

    bisco cookie crumbler

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    doubt the fuse, but not sure. check youtube for video instructions. particularly nutzaboutbolts if he has one.
     
  6. memento1984

    memento1984 Junior Member

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    Bisco, do You think this (air in the cooling system/engine loop) would trigger this error code (P261C/C*) or the pump is fried at this point ?
     
  7. bisco

    bisco cookie crumbler

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    i can't answer that, but iirc, air can cause some funny things to happen, and prius is notorious, because the bleed process is a bit more complicated. it's worth checking.
     
  8. memento1984

    memento1984 Junior Member

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    interesting, I have noticed that since I came back from that trip, the overflow tank level was dropping, almost as if it was sucked in, rather quickly. I was putting ~1.2qt twice - I could only see fluid at the very bottom connection of the overflow tank. I belive it is low now too - so maybe a lot of dead air space....
    that nuztandbolts video is excellent.
     
  9. bisco

    bisco cookie crumbler

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    you need to remove the cowling over the radiator, and check the level there. don't go by the reservoir. are you seeing any coolant around the water pump, on the ground and etc.?
     
  10. memento1984

    memento1984 Junior Member

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    no leaking at all, no dripping etc. So i started that flushing sequence - filled it a little over, some bubbles were coming out of reservoir, not sure if it was from lower or upper return hose. fluid level was going up and down with occasional bubling, and a lot of water was pushed out. then the engine got operating temperature (fans turned on) and then I got my old "check hybrid system" and car turned the combustion engine off.
     
  11. bisco

    bisco cookie crumbler

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    does that nail it down to the water pump?
     
  12. memento1984

    memento1984 Junior Member

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    I think it does, there was not much movement of liquid, just kind of boiling and pushing liquid out - I am almost sure that radiator was cold. I wonder if I should replace thermostat while at the pump (tstat was my initial guess, since radiator was not hot, before triangle of death and reading the ODB codes) ?

    still waiting for the pump...
     
    #12 memento1984, Aug 16, 2017
    Last edited: Aug 16, 2017
  13. NutzAboutBolts

    NutzAboutBolts Senior Member

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    You should invest in a mini VCI, you can make the water pump work with techstream and check the operation. Someone this week had their water pump replaced because their water pump wasn't working sufficiently due to the magnet bearing I believe, after the engine was at 95c the water pump stopped working and made the engine overheated. I don't remember which thread but he replaced the water pump and the overheating problem went away. I'll do more research later since I'm on my phone.

    Edit:

    I just checked, his CEL is P261B
    Water pump failure Symptoms | PriusChat
     
    #13 NutzAboutBolts, Aug 17, 2017
    Last edited: Aug 17, 2017
  14. NutzAboutBolts

    NutzAboutBolts Senior Member

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    So I just checked the CEL P261C for you, it is "Short in coolant pump "B" Control Circuit and the 3 trouble area is

    - Short in water pump assembly circuit (you might need techstream to see if the water pump is working properly and see if there are any RPM to see if its short or not)
    - Water pump assembly (possible since your engine is overheating)
    - ECM (not possible since everything else works)

    I would replace your water pump and see if the overheating helps. Just like in the other thread, his water pump failed on him and once he replaced it, it worked perfectly without overheating issue.
     
  15. memento1984

    memento1984 Junior Member

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    great point, this was my thought too. will update once replaced.
    great video on that intake manifold! this will help a lot with access, at least from the upper side. bottom bolts I guess can be reached from under, unless I can get some extensions.
    what was the bolt size ?
    thanks!
     
  16. NutzAboutBolts

    NutzAboutBolts Senior Member

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    here's the files for you.
     

    Attached Files:

  17. memento1984

    memento1984 Junior Member

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    I wonder, those plastic clips, that hold the pump on the engine - they will pop out with gentle prying ? they seem to be just holding the pump while we start putting the bolts back.
    thank You for pdfs!
     
  18. Raytheeagle

    Raytheeagle Senior Member

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  19. memento84

    memento84 Junior Member

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    replaced pump reconnected everything and the same error persists (actually both of error come up, P261C and P261C* together, whatever the asterisk means).
    Is there any way that this is due to FUSE or RELAY ?
    where to look for it ?
     
  20. NutzAboutBolts

    NutzAboutBolts Senior Member

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    did you erase the codes?