2010 Prius Trim 5 engine revving on it's own

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by PaulMarshall, Dec 7, 2020.

  1. PaulMarshall

    PaulMarshall Junior Member

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    It has been doing it frequently the last week. I hear it a lot when I come off the freeway, my foot will be on the brake... nowhere near gas pedal. I've even put it in park at traffic light at when it's doing it and taken foot off all pedals... still does it. Other times the ICE will never shut off even though I'm at full bars on traction battery. when it's doing this it will have a rough loping sound like a cylinder is missing. I do door dash for a living till covid is over, if I go sit in a parking lot and turn the car off for 10 to 15 minutes it starts acting normal again for a while. I just happened to get lucky enough to be getting out of the car last night to get an external video where you can hear the engine idling at around 2500rpm. Usually it's harder to hear on previous videos I tried to capture it on, due to the it being muffled because I was in the car (muffled by cabin insulation). any suggestions? My initial thoughts are ECU malfunctioning. No check engine light or anything have ever lit up though.

    I have techstream cable and software just need to round up a laptop that will run windows 7.

    Any suggestions as to where to start looking?

    Video attached of 1 of the two (over rev). I haven't gotten a video yet of when it's sounds like a cylinder isn't firing.

     
    #1 PaulMarshall, Dec 7, 2020
  2. sam spade 2

    sam spade 2 Senior Member

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    Start by being sure that your 12 V battery and it's connections are good. I mean really sure.

    Then.....what you are describing often is an early warning sign that there is problem developing with the HV hybrid battery or it's internal connections.
     
    #2 sam spade 2, Dec 7, 2020
  3. PaulMarshall

    PaulMarshall Junior Member

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    I should have mentioned that. The 12V battery was just changed out 3 months ago. The only one in stock locally was the house brand of O'Reilly's battery line. I'll double check the connectors, but I'm pretty sure that shouldn't be the problem.
     
    #3 PaulMarshall, Dec 7, 2020
  4. PaulMarshall

    PaulMarshall Junior Member

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    And eeep on the second part. It's a 10 year old car, but low miles (bought it last year with 74k miles). It was a short daily commute driver in downtown Nashville TN.

    My first prius was a second gen 04 prius and it made it to 240k miles and lasted till 2018. I managed to find a guy within 100 miles of me who rebuilds batteries for second gen's with new buss bars, new cells for the failed ones and balanced the cells. The rebuilt traction battery on my 04 was working great, until some jackhat pulled out straight in front of me and totaled that one.

    That'll totally suck if it's the traction battery at only 100k miles.
     
    #4 PaulMarshall, Dec 7, 2020
  5. bisco

    bisco cookie crumbler

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    consider the egr circuit as well, you should change your model year.
     
    #5 bisco, Dec 7, 2020
    Mendel Leisk likes this.
  6. tankyuong

    tankyuong Senior Member

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    Check 12v battery voltage even if it's new
     
    #6 tankyuong, Dec 7, 2020
  7. sam spade 2

    sam spade 2 Senior Member

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    Worth repeating.
    Even NEW batteries can be bad sometimes.
    3 year old batteries can certainly be bad, especially if it wasn't fully charged to start with OR it had been sitting in the warehouse for a few years before you got it.
     
    #7 sam spade 2, Dec 7, 2020
  8. Grit

    Grit Senior Member

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    That would mean troubleshooting the easy stuff first, overachievers would never buy into that.
     
    #8 Grit, Dec 8, 2020
  9. sam spade 2

    sam spade 2 Senior Member

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    Sure. That's one word for it.
    :ROFLMAO:
     
    #9 sam spade 2, Dec 8, 2020
  10. AzusaPrius

    AzusaPrius Senior Member

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    Im willing to bet that once he gets an old laptop and pulls codes that it is the hybrid traction battery.

    Get an obd2 bluetooth reader and the Dr. Prius App.

    Sounds like the engine is trying to keep it charged because it is draining too fast and is weak and will sure throw a code very soon.

    It is not even hot outside to cause that and you have the same issue as with weak batteries.




    Posted via the PriusChat mobile app.
     
    #10 AzusaPrius, Dec 8, 2020
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