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Check engine light on : Code P261B

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by CorbinDallas, Aug 14, 2023.

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  1. CorbinDallas

    CorbinDallas New Member

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    Hello fellow Prius enthusiasts,

    This is my first post here, so a bit of an introduction:

    I drive a 2017 Prius Two with almost 200,000 miles on it, most of these miles being rideshare miles. The only problem I have ever had with her was a leaky radiator around 140k, which was replaced. Other than that, I have had zero problems until this.

    A few weeks ago, my check engine light started to come on. It will stay on for a few days and then turn off for a couple of days and keeps turning on and off intermittently. Took the old girl to PepBoys to see what code it was. I have attached an image of what the code reader said: Code P261B: Coolant Pump "B" Control - Circuit Range/ Performance.

    (Note: my back seat seatbelt alarms have been starting to off on their own without anyone sitting in the seats recently too, I'm not sure if these two things are related. I've had thousands of people in the back seat so I'm not surprised about this)

    I don't want to spend a bunch of money if I don't need to. She does not appear to be overheating (she would turn off if this was the case) and runs perfectly. I have always kept up with all recommended maintenance. Is anyone here familiar with this particular problem? Has this happened to you? Any insight / advice will be appreciated. Thank you

    Regards

    Joe
     

    Attached Files:

    #1 CorbinDallas, Aug 14, 2023
  2. AzusaPrius

    AzusaPrius Senior Member

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    Change the water pump asap.

    Unless you want to rebuild or buy another engine.
     
    #2 AzusaPrius, Aug 15, 2023
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  3. JohnPrius21

    JohnPrius21 Junior Member

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    How’s the engine coolant level? When was the coolant last changed?
     
    #3 JohnPrius21, Aug 16, 2023
  4. CorbinDallas

    CorbinDallas New Member

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    There is a chance that it isn't actually the water pump and may be an electrical issue. The pump itself may still be fine.

    Coolant is fine. Was topped off at last oil change. I will check it again though.
     
    #4 CorbinDallas, Aug 16, 2023
  5. AzusaPrius

    AzusaPrius Senior Member

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    Mmm nope pretty sure it means your water pump is not moving fast enough.

    Makes sense that you had to top off the coolant too.

    You may hear a chirp like sound coming from that area or over heat light but it is easy to miss.

    I would keep an eye on the temp with an app or P10 device.
     
    #5 AzusaPrius, Aug 16, 2023
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  6. ChapmanF

    ChapmanF Senior Member

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    There are other P261x codes more likely for an electrical issue. P261B is really about a reading < 900 RPM from the pump tachometer. (Which tells us the signal from the pump tachometer is getting to the ECM, which suggests the wiring is probably ok.)
     
    #6 ChapmanF, Aug 16, 2023
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  7. CorbinDallas

    CorbinDallas New Member

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    Thanks. I'm bringing it in to the dealership on Tuesday. The reason I thought it might be a relay problem is because the check engine light keeps going on and off but you are probably right.

    Now let me ask you something. Are OEM water pumps and aftermarket water pumps for this particular car the same thing or should I spring for the Genuine Toyota part?
     
    #7 CorbinDallas, Aug 16, 2023
  8. AzusaPrius

    AzusaPrius Senior Member

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    I would only get OEM or AISIN, they make the water pumps for Toyota.

    You will find that some AISIN water pumps have grinded off the Toyota logo.
     
    #8 AzusaPrius, Aug 17, 2023
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  9. ChapmanF

    ChapmanF Senior Member

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    Which, to the curious buyer, invites the question: what are Aisin's criteria for deciding which pumps go to Toyota, and which ones get the Toyota logo ground off and sold in other channels?
     
    #9 ChapmanF, Aug 17, 2023
  10. AzusaPrius

    AzusaPrius Senior Member

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    I believe it is possible that Toyota returns new old stock to AISIN and then they grind off the Toyota logo.

    Nothing is different about the two.

    Any damaged pumps would be marked as such and refurbished and labeled as RB or refurbished.

    AISIN is not going to resale damaged returns from Toyota without testing them.

    They are not lower quality, they are exactly the same product.

    Toyota does not modify the pumps in any way and they would just make their own if that were the case and leave AISIN out of it.
     
    #10 AzusaPrius, Aug 17, 2023
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  11. vvillovv

    vvillovv Senior Member

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    @AzusaPrius Thanks for the info. I did a bit of looking around and found this priuschat post with video that should clear up a lot about the Prius water pump install. Posted by @Peter123 - 3 years ago.
    Aisin Water Pump Video with Coolant Bleed Instructions | PriusChat

    I'm happy to report the part about putting the Prius into maintenance mode also worked in my 2017 Prius Prime. I'd done it ( put the prius into maintenance mode ) with the Gen 3 PiP one time, but I'd forgotten the sequence of steps.

    useful?
     
    #11 vvillovv, Aug 17, 2023
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  12. ChapmanF

    ChapmanF Senior Member

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    It would be great to know how you think you know all that.
     
    #12 ChapmanF, Aug 17, 2023
  13. vvillovv

    vvillovv Senior Member

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    search terms aisin same as toyota oem
    should get as close to an answer to that question as I think is possible on this side of the two ponds.

    look for the wiki page
     
    #13 vvillovv, Aug 18, 2023
  14. Mr.Vanvandenburg

    Mr.Vanvandenburg Senior Member

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    A couple times on an older Toyota I paid the $20 for a short term access to the repair manual. Then go through testing the water pump as it shows. Then I download as much other info as I can during the access time.
     
    #14 Mr.Vanvandenburg, Aug 18, 2023
  15. ChapmanF

    ChapmanF Senior Member

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    That is a surefire technique when the question being asked is "what does a sample of the internet think they know about something?".
     
    #15 ChapmanF, Aug 18, 2023
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  16. AzusaPrius

    AzusaPrius Senior Member

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    I do not know why chap is not getting it.

    AISIN is the OEM part for Toyota.

    They just stamp Toyota on it for branding.

    Obviously AISIN is going to grind off Toyota when they resell the parts that Toyota had from them.

    Why? Well maybe that very same pump is used on another car and lets say that car was a Honda, well the person or company who gets the part from AISIN is not going to want a Toyota stamp on their pump.

    Should they leave the Toyota stamp on?

    Would that make you not question if it is Toyota?

    Even though it is clearly made by AISIN.

    Maybe Toyota should grind off the AISIN?

    Nah... This is way too simple to understand.
     
    #16 AzusaPrius, Aug 18, 2023
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  17. Mr.Vanvandenburg

    Mr.Vanvandenburg Senior Member

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    Maybe it’s just the casting Aisin uses and Toyota is ground off, but Toyota specs specific internals based on their own r&d? I have an Aisin for my truck still in the box, was wondering what was ground off.
     
    #17 Mr.Vanvandenburg, Aug 18, 2023
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  18. ChapmanF

    ChapmanF Senior Member

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    I don't know why Azusa's not getting it.

    A manufacturer can use all kinds of criteria to decide which items out of a production run will be shipped to the contract purchaser and which ones will have the purchaser's logo ground off and be sold some other way.

    Does Azusa think those decisions are being made by flipping coins?

    Heck, maybe they are. I don't know, and neither does Azusa. But neither of us was born yesterday, so we both know that's the question.
     
    #18 ChapmanF, Aug 18, 2023
  19. vvillovv

    vvillovv Senior Member

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    chap
    here's a hint link
    Aisin president is remaking the Japanese megasupplier | Automotive News

    and here's the meat and potatos link
    https://en.wikipedia.org/wiki/Aisin

    at least this is how I read it

    the wiki page I read a few days ago when I posted #13 said a wholly owned subsidiary of Toyota group in big letters at the top.
     
    #19 vvillovv, Aug 20, 2023
    Last edited: Aug 20, 2023
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  20. ChapmanF

    ChapmanF Senior Member

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    It's as if the question "how do they select which units produced get sent to which sales channels?" cannot be spelled in big enough letters for some people to see it.
     
    #20 ChapmanF, Aug 21, 2023
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