Engine Code P261B Water Pump

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Jon Batchelor, Mar 3, 2026 at 2:14 PM.

  1. Jon Batchelor

    Jon Batchelor Junior Member

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    Had this error code come up today from a check engine light. Dealership says they are trimming all the fat they can, and want to charge me $500 parts, $500 labor for it. I trust my dealership, but I just flat out cannot afford that.

    From all I can read, the water pump in question is the smaller, less expensive silver/gray one for the engine, not the one for the inverter? Luckily, after watching videos regarding each, also seems to be the one that is easier to reach of the two.

    I can get an Aisin PWT-190 (the one who manufactures them for Toyota) for less than $150, and have a friend who could install it. (While he hasn't worked on hybrids, he's done plenty of things like timing belts and non-hybrid water pumps in the past, and like I said, this one looks much easier to access and replace than the inverter pump.)

    Was even considering just trying to replace the impeller, but it doesn't look like those are sold by higher level companies (Toyota, Aisin), and the low end ones are rumored to only last a short time, so probably better to replace the whole thing.

    Thoughts on this? Anyone? Anything I'm not yet taking into account?
     
    #1 Jon Batchelor, Mar 3, 2026 at 2:14 PM
  2. bisco

    bisco cookie crumbler

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    #2 bisco, Mar 4, 2026 at 2:32 PM
  3. Brian1954

    Brian1954 Senior Member

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    Code P261B is for the engine water pump. The water pump is not rotating fast enough. Get it replaced ASAP because the engine will overheat and possibly cause a problem with the head gasket. Overheating will occur when going uphills or traveling on a highway (60 mph and higher).
     
    #3 Brian1954, Mar 4, 2026 at 2:35 PM
  4. Mendel Leisk

    Mendel Leisk MMX GEN III

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    I'd go with the Aisin (WPT-190), from a reputable source. Plan to do that proactively (plus the thermostat), IF we ever make it to 100k miles. Most likely in conjunction with an engine coolant change.

    What's the miles on your btw    ? They have a tendency to fail around 125~150k miles.

    @NutzAboutBolts video #29 here is a good one.

    Being in Canada, I'll likely go with this source, $151.51 CDN, all-in, on my doorstep ($110.60 USD)
     
    #4 Mendel Leisk, Mar 4, 2026 at 2:42 PM
  5. Jon Batchelor

    Jon Batchelor Junior Member

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    320k miles. There was a reason I wanted to stay with Toyota/Aisin. These cars are incredible.



    This is what I am looking at, from the Aisin store on amazon. Perhaps I should suggest the thermostat at the same time, just because of the high mileage and being there anyway.

    [edit]Seems it's not showing the amazon link, but it's Aisin WPT-190 from the Aisin store for 138.17.[/edit]
     
    #5 Jon Batchelor, Mar 4, 2026 at 3:59 PM
    Last edited: Mar 4, 2026 at 4:07 PM
  6. PriusCamper

    PriusCamper Senior Member

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    It's a super easy job, there's plenty of youtube videos on how to do it and Aisin aftermarket pumps are way cheaper and not any different than OEM. If you lived near me It'd be about $200ish total including cost of part.
     
    #6 PriusCamper, Mar 4, 2026 at 4:49 PM
  7. Jon Batchelor

    Jon Batchelor Junior Member

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    And yet the person who was lined up to do it called off, saying he didn't have the proper tools, and something about snapping the drive shaft if you didn't do things just right.

    Looking at the video, it didn't look that difficult to me. Sigh.
     
    #7 Jon Batchelor, Mar 4, 2026 at 4:53 PM
  8. Jon Batchelor

    Jon Batchelor Junior Member

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    Unfortunately, it would be quite difficult to get further away ;)
     
    #8 Jon Batchelor, Mar 4, 2026 at 4:54 PM
  9. BiomedO1

    BiomedO1 Senior Member

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    I would replace the entire assembly; because I don't like doing the same job twice.

    I would also install some sort of ECT monitor, because the dummy lamp doesn't light up until your pass 248+F when nominal should be 185-205F. Your lucky to get that P261B, some people just pop their head gasket before figuring that out or run out of coolant.

    Good Luck.....
     
    #9 BiomedO1, Mar 4, 2026 at 5:01 PM
    Brian1954 likes this.
  10. Jon Batchelor

    Jon Batchelor Junior Member

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    Besides, after 320k miles, why risk anything else going wrong by just replacing one part of it? Going for the whole thing.
     
    #10 Jon Batchelor, Mar 4, 2026 at 5:09 PM
  11. ASRDogman

    ASRDogman Senior Member

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    $500 for the water pump is high, labor seems a bit high also.

    It's a pretty simple job. Just fill the system very slowly, and a cup or two at a time.
    Doing so allows the coolant to push out the air, and not get trapped.

    Don't get it from ebay or amazon, likely a cheap chinese copy. Try an auto parts store.

    I replaced the impeller in mine at 266710 miles, 4 years ago. I have 384,6xx miles.
    Right at 122,000 miles ago. No issues.



     
    #11 ASRDogman, Mar 4, 2026 at 5:41 PM
  12. Jon Batchelor

    Jon Batchelor Junior Member

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    Is the Aisin store on amazon not actually Aisin?
     
    #12 Jon Batchelor, Mar 4, 2026 at 6:20 PM
  13. PriusCamper

    PriusCamper Senior Member

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    Yep...
     
    #13 PriusCamper, Mar 4, 2026 at 6:58 PM
  14. ASRDogman

    ASRDogman Senior Member

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    No one knows for sure. But for certainty, amazon has a LOT of cheap chinese copies.....

    Why risk it. How often do you plan on replacing the coolant pump? Every 11 years?

     
    #14 ASRDogman, Mar 4, 2026 at 7:13 PM
  15. ChapmanF

    ChapmanF Senior Member

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    There might be people who do know for sure. My only problem is I don't know for sure who they are.
     
    #15 ChapmanF, Mar 4, 2026 at 8:45 PM
  16. Jon Batchelor

    Jon Batchelor Junior Member

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    Well, at this point, I'm considering making sure the product is sent directly to me, to check it for signs (proper packaging, gasket present, but not already in place, hopefully signs of Toyota scraped off), or biting the bullet, letting a friend pay the $1000, letting the dealership do it, and hoping I can eventually manage to fully pay them back.

    I hate scammers.
     
    #16 Jon Batchelor, Mar 4, 2026 at 8:56 PM
  17. ASRDogman

    ASRDogman Senior Member

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    Just have your friend watch a few youtube videos. It's not different than a non hybrid.
    With a minor exception. Remove the service switch on the hybrid battery. And make sure
    he reinstalls it correctly.

    You can find a Toyota coolant pump for less than $500 from other Toyota dealerships online.
    You may even get a 10% military discount.
    And get the TOYOTA 50/50 coolant! 2 gallons. Do not get substitutes.

     
    #17 ASRDogman, Mar 4, 2026 at 9:03 PM
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