P261B, high coolant temp light,, water pump?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Johhhn, Feb 13, 2022.

  1. Johhhn

    Johhhn Junior Member

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    ran the codes for the CE light/hybrid system warning that popped up last night and a couple weekends ago. I got P261B and everyone says it's the water pump.

    I've also read that some people replace it and still have the problem. Would the high coolant temp light indicate it's the pump for sure? It's a 2011 Prius with 160K miles.

    thanks!
     
  2. ChapmanF

    ChapmanF Senior Member

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    P261B means the water pump has been clocked at under 900 RPM when it should be more than that.

    Pretty commonly that'll be the pump. If you want to be more sure before you replace it, you can follow the troubleshooting workup for that code in the repair manual (more info).
     
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  3. sam spade 2

    sam spade 2 Senior Member

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    NO. It could be several things, including a leak and low coolant level.
     
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  4. Johhhn

    Johhhn Junior Member

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    I added coolant yesterday and did about a 3 hr roundtrip drive and the coolant is about an inch below the F, and I noticed coolant in the areas where I circled in blue. Thoughts? I checked the wiring plug to the water pump and it looks fine and I didn't see any leaks below the water pump.

     

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    #4 Johhhn, Feb 13, 2022
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  5. Johhhn

    Johhhn Junior Member

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    In addition to what I wrote above, I just noticed that there's a high pitch "whine" in the engine bay near the water pump when the car is on (engine not running).
     
  6. Johhhn

    Johhhn Junior Member

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    one other thing-- I just ran my car in maintenance mode and the radiator fan never turned on. It ran long enough to where you can hear the engine RPM change, but the fans never kicked on- does this sound normal?
     
  7. ttou68

    ttou68 Active Member

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    It was the water pump the last time I experienced that code...
    It doesn't hurt to take out the pump and spin it by hand to see any resistance... Mine was seized

    Posted via the PriusChat mobile app.
     
    #7 ttou68, Feb 13, 2022
    Last edited: Feb 14, 2022
  8. Johhhn

    Johhhn Junior Member

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    OT? not sure what that stands for,,, thanks
     
  9. rjparker

    rjparker Tu Humilde Sirviente

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    What that light means "for sure" is the engine is way too hot and running it for three hours is a sure way to blow a head gasket in an all aluminum engine. Spewing coolant out of the cap is another sure sign that its way too hot.

    As Chapman and "everyone" indicates, the code says change the pump. It seems quite a few people have trouble believing folks these days.

    I tell my wife and friends they need to pull over safely and have the car towed if they see a temperature light. I also monitor it in my car so that I might get an early heads up on an over temperature.

    Prius P10 Scanner.jpg
     
    #9 rjparker, Feb 13, 2022
    Last edited: Feb 13, 2022
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  10. Johhhn

    Johhhn Junior Member

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    I'm trying to maximize my troubleshooting :) I've already ordered a water pump and plan on removing it tomorrow to check if it's seized.

    Any idea about the radiator fan not coming on?

    And thank you for your input! :)
     
  11. Johhhn

    Johhhn Junior Member

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    That display is super slick- where can I find this mod?
     
  12. rjparker

    rjparker Tu Humilde Sirviente

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    It can take 30 minutes to operate the radiator fan. Usually turning on the ac will test it. When driving the fan is rarely needed.

    The display is a "P10 HUD OBD2", ebay.
     
    #12 rjparker, Feb 13, 2022
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  13. Johhhn

    Johhhn Junior Member

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    Thanks,, it was running close to that. I figured once I heard the RPMs change, it should have kicked in. Regardless, will find out tomorrow once I pull the pump out.
     
  14. ChapmanF

    ChapmanF Senior Member

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    I can't speak for "everyone" but what I said was a little different ... because I'm always harping on the "trouble codes don't tell you to do something, they give you info about a situation" business, I'd break character to stop now.

    The info that P261B gives you is that you have a situation where the tachometer signal from the pump is being read as less than 900 RPM, when the pump should be going faster than that.

    I suggested that the reason for the pump RPM being too low has commonly turned out to be the pump itself, but that's me talking, not the code. And there can be exceptions, like more rarely a wiring problem getting power to the pump. Or even a problem with the tach signal coming back from the pump. So if a person wanted to go through the P261B troubleshooting workup before just condemning the pump, that wouldn't be an insane thing to do.

    Other people will see the code and go straight for the pump, and that's not insane either, since that will be the culprit often enough.
     
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  15. rjparker

    rjparker Tu Humilde Sirviente

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    When the writing is on the wall and ignoring it is risking the engine because of overtemp and your family by getting stranded, its time to act. Expecting everyone (no quote) to be an Ivan with a Picoscope and a milliohm meter is a bit much.
     
  16. ttou68

    ttou68 Active Member

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    Should have been "It"... Typo, my bad...

    Also, just to note that I also heard that noise and felt vibration came from water pump when I received the code, and noise and vibration both gone after I unplugged the pump.
    Posted via the PriusChat mobile app.
     
    #16 ttou68, Feb 14, 2022
    Last edited: Feb 14, 2022
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  17. sam spade 2

    sam spade 2 Senior Member

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    Some people have a tendency to beat things to death and seem to be waiting for the bad part to jump out and grab them by the nads.
    :eek:
    :ROFLMAO:
     
  18. ChapmanF

    ChapmanF Senior Member

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    Agreed that an issue involving overheat needs to be solved without wasting time, and that the owner (or mechanic) needs to take an honest look at his or her own situation, skills, and available tools and resources.

    If it is practical to follow the troubleshooting steps for the indicated problem—promptly—that will be the straightest path to a correct solution without misspent cash, repeat problems, and do-overs.

    If that isn't practical, of course no one is saying "do nothing" is an option. Progress still has to get made somehow, even if it's by guessing at a likely part and spending the money to see if that does the trick. Sometimes it won't, but it can be a reasonable gamble for someone who knowingly chooses it.
     
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  19. Johhhn

    Johhhn Junior Member

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    My communication may not have been clear enough. My first error message was the Check Hybrid System two weeks ago Saturdays. I noticed the coolant being an inch lower from Full on Saturday (two days ago) and I topped it off. And then the coolant temp and CE came up on the way home (30 mins away) this past Saturday night. Yesterday I scanned the code and voila, here I am.

    I problem solve and troubleshoot things on the daily with technology (computers), and so eliminating all possibilities is important. That doesn't mean I'm not ignoring the most likely problem (water pump).. after all, I am here because people in this forum have a ton more experience than I do with Prius'.

    Asking questions is important and a part of the learning process, and I get it.. it can be frustrating sometimes when it seems that people aren't 'listening'. I assure you that is not happening here. Thank you and everyone else for advice! :)
     
  20. Johhhn

    Johhhn Junior Member

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    Drained coolant from the radiator- coolant looked brand new (don't think it's been changed), and pulled the water pump out.

    It spins freely and there's no cracks on the impeller or white housing as seen on the photo. You can definitely see and feel the areas where it's worn. I thought it would be worse considering the code it threw and the temp warning light.

    New pump and OBD2 Bluetooth should be inn tomorrow!
     

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