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Engine rpms stay high after pedal release, mpg way down.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Joecasciojr, Jul 6, 2017.

  1. JC91006

    JC91006 Senior Member

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    Everything seems normal because of the hot weather, the battery's hot.

    Once the battery temperature rises nothing seems to work correctly. If she drives the car at 9 at night I'll bet you everything will seem normal to her
     
    #21 JC91006, Jul 19, 2018
    Last edited: Jul 19, 2018
  2. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Told her when she got home to park it in the shade and leave it running so the battery can keep cooling. When I got there it had been sitting 30 mins of running. Drove it and was all good, must have overheated!
     
    Robert Holt likes this.
  3. JC91006

    JC91006 Senior Member

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    I get this symptom with all my cars. It's related to a HV battery getting too hot. When the battery gets hot the car somehow doesn't pull power from it, so it runs exactly like the battery SOC is at 1 bar.
     
  4. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Makes perfect sense, and it's good that it takes care of its battery so well. Sistsr said she had to floor it when she pulled out of the parking lot and it worried her.
     
  5. JC91006

    JC91006 Senior Member

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    This is something else Toyota should look into, kinda dangerous. Get a recall so they put in a switch to turn on the battery cooling fan manually, to cool the battery.
     
    Bay Stater, Aaron Vitolins and Grit like this.
  6. RMB

    RMB Senior Member

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    There was this one time in early May we hit a heat wave here in the Bay Area, on my commute home in the afternoon while stuck in stop and go freeway traffic, the ICE ran for 13 straight minutes due to 1) high battery temp, 2) AC on and not enough regen with the stop and roll driving. Horrible mileage on that trip home. Usually when the HV battery gets down to 2 bars the ICE runs 3 mins to charge up the battery.
     
  7. Raytheeagle

    Raytheeagle Senior Member

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    It got hot in Oakland :whistle:?

    Must have been triple digits over here:eek:.
     
    Bay Stater and Grit like this.
  8. Grit

    Grit Senior Member

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    107 in my neck of the woods earlier today.
     
    Bay Stater and Raytheeagle like this.
  9. Grit

    Grit Senior Member

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    Want to jimmy rig the fan run at its highest speed when car is on ready myself.
     
  10. RMB

    RMB Senior Member

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    My Prius and I both got spoiled with the 72 F summer in Oakland:sneaky:, when it gets to 90 both me and my Pearl are screaming for max AC. :ROFLMAO:
     
  11. Welshdog

    Welshdog Member

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    It certainly has been hot here in Austin lately and the climate control is always on, always. So if these conditions cause this RPMs to hang, then that might be it. However, it's not like high temps in Austin is a new thing - 100ยบ plus days are normal in June, July, August and September. I can't help but think some other parameter in the equation has changed.
     
  12. Jason Franciosa

    Jason Franciosa New Member

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    I am experiencing this issue as well. It happens at night when temps are cool. Did anyone resolve this? I'm not fully understanding how the 12v battery could be involved in this. I have a 2013 prius and have never changed the 12v, It may be due. Could this be the issue?

    Autozone is saying it probably is the throttle position sensor, but, i have no check engine light.