p261b, stop and go, power cycle rapid temp drop, triangle, coolant pump

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ben Schneider, Feb 24, 2019.

  1. Ben Schneider

    Ben Schneider Junior Member

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    started getting triangle code + p261b... changed trans oil and coolants...

    mostly went away

    car mostly around 190f regularly

    codes happen when a/c on for a while and/or especially in stop and go traffic.

    drove yesterday in 90 degree weather for 3 hours mostly non stop - code came up in stop and go traffic (where it seems to usually come up), engine temp climbing to 220f

    i pulled over, turned car off, then turned it on 2 seconds later. engine temp rapidly went down to 186f, in about 30 seconds.


    ready to change coolant pump if necessary, but strange that overheating does not happen all the time and strange that turning the car off and on right away causes a 30 degree temp drop back to normal
     
  2. Ben Schneider

    Ben Schneider Junior Member

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    also it seems like as there is some heat in the engine there are momentary reductions in hp
     
  3. tankyuong

    tankyuong Senior Member

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    Thermostat?
     
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  4. Raytheeagle

    Raytheeagle Senior Member

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    How many miles on your Prius?
     
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  5. Ben Schneider

    Ben Schneider Junior Member

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    that is a good guess, though, how would the temperature go down fast after a power cycle
     
  6. Ben Schneider

    Ben Schneider Junior Member

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    190k
     
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  7. Raytheeagle

    Raytheeagle Senior Member

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    Make sure all connections are tight, but there have been accounts of the water pump failing;).

    I would replace both the thermostat and pump just to make sure you get either cause:).

    Good luck and keep us posted (y).
     
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  8. Ben Schneider

    Ben Schneider Junior Member

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    i will check the connections... there don't seem to be any leaks

    tempting to replace those, but i don't yet want to do guessing game that becomes a money pit

    appreciated.
     
  9. Raytheeagle

    Raytheeagle Senior Member

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    If you do the same and continue to drive it, you’ll be repairing many more components ;).

    Ensure you have a good code reader to catch all the codes and then prioritize the work. Good luck and keep us posted (y).
     
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  10. tweedle99

    tweedle99 Member

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    I had the same code and was able to get home after restarting the car. Replaced the pump and the code went away permanently. The pump impeller appear to be turning fine but has a little more resistance. It probably throw codes when it stop spinning. I would replace the pump before other components fail, like Ray said above.

    Pretty easy to change out, just take out the air snorkel. I didn't change out the thermostat but hindsight, should have.
     
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  11. Ben Schneider

    Ben Schneider Junior Member

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    i truly appreciate your advice...

    went to tampa hybrids (they basically only sell priuses) yesterday. they were pretty sure it is the pump. though the assistant started checking the inverter stuff and squeezing the hoses when i asked him to check the wiring.

    going to replace the pump and probably the thermostat ... i am seeing the temp on some thermostats as 180 - is that the right temp ?
     
  12. tankyuong

    tankyuong Senior Member

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    Average is in the 190s
     
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  13. tweedle99

    tweedle99 Member

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    Might as well do coolant flush while you are at it since you are already draining the coolant, if you haven't done so.
     
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  14. Raytheeagle

    Raytheeagle Senior Member

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    Clean the egr circuit since you’ll have the coolant out and the mileage is up there;).

    Good luck and keep us posted (y).
     
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  15. Ben Schneider

    Ben Schneider Junior Member

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    was attempting to change pump a few minutes ago...

    got 2 bolts off

    there was a 1/2" aluminum pipe with a diamond washer at the bottom ( in the way of one bolt so i began to disconnect it (10mm) and it seems to have depressurized or something... anyone know what that is... i hope not bad
     
  16. tweedle99

    tweedle99 Member

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    you can try taking off the fender liner to get to the bolts. No need to jack up the car, just turn the wheel out.
     
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  17. Raytheeagle

    Raytheeagle Senior Member

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    Pretty sure that’s the ac system:cool:.
     
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  18. Ben Schneider

    Ben Schneider Junior Member

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    location in pink (this is not my photo, borrowed from net) - i tried to move a thin aluminum pipe to better get at the bolts... then a rapid depressurization of something - did i depressurize ac ?
     
  19. Ben Schneider

    Ben Schneider Junior Member

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    did it, ty
     
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