1. Attachments are working again! Check out this thread for more details and to report any other bugs.

09 Prius Randomly total loss of memory and restart when turn off car

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Cheffaz, Nov 30, 2021.

  1. Cheffaz

    Cheffaz Junior Member

    Joined:
    Feb 13, 2011
    32
    3
    0
    Location:
    Woodlyn
    Vehicle:
    2009 Prius
    Model:
    Five
    09 Prius Randomly total loss of memory and restart when turn off car.

    only happens when you turn off the car. not when driving.

    HV battery? Inverter? any ideas would be helpful.

    Thanks
     
  2. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,490
    14,095
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    What leads to this conclusion? I'm thinking: drives rough, bad fuel economy, clock reset, radio presets gone, phonebook wiped, etc.

    At any rate, the traction battery and inverter would have no effect on anything like that. But a loose connection on the 12v might do some weird things. If you tell us what you observe, it would be helpful.
     
    Cheffaz likes this.
  3. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    Everything about this screams 12v battery or 12v battery connections..........
     
    Mendel Leisk and Cheffaz like this.
  4. Cheffaz

    Cheffaz Junior Member

    Joined:
    Feb 13, 2011
    32
    3
    0
    Location:
    Woodlyn
    Vehicle:
    2009 Prius
    Model:
    Five
    I will check the battery connections later today. Thanks!
     
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    be sure to check negative connection to body
     
    Cheffaz likes this.
  6. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    A healthy 12 volt battery in this car lives at around 12.6 volts.

    When testing 12 volt battery condition always use the front jump point. It does not matter what it measures at the battery only matters what’s hitting the front fuse box.

    If your battery is over 5 years old and has been sitting a lot from covid
    Just replace it. In the reinstallation you may discover the loose connections.
    Plus you can clean all the water out of the battery hole.
     
  7. Cheffaz

    Cheffaz Junior Member

    Joined:
    Feb 13, 2011
    32
    3
    0
    Location:
    Woodlyn
    Vehicle:
    2009 Prius
    Model:
    Five
    All connections are now tight and one seemed loose, and it hasn't happened since tightening. this may have fixed the problem, i will report back in a few days...
     
    nancytheprius and bisco like this.
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    thanks! i hope that is it.
     
  9. Cheffaz

    Cheffaz Junior Member

    Joined:
    Feb 13, 2011
    32
    3
    0
    Location:
    Woodlyn
    Vehicle:
    2009 Prius
    Model:
    Five
    funny thing it happened once again yesterday but who knows.... could it be the hv battery dying its the original battery and I have a new optima yellow top so i know its not that
     
  10. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,072
    14,976
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Nope, that was ruled out when you said this:

    So your issue only happens at times when the traction battery is out of the picture.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,474
    38,105
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    You could test it, or have it tested. It's a little more advanced than just a voltage test; not sure of the best term to search would be, maybe electronic automotive load tester. I use a Solar BA5, current model is BA9. Ancel comes up a lot, on Amazon. A lot of automotive retailers selling batteries will have a pro-level tester, and be willing to test for free.
     
  12. Cheffaz

    Cheffaz Junior Member

    Joined:
    Feb 13, 2011
    32
    3
    0
    Location:
    Woodlyn
    Vehicle:
    2009 Prius
    Model:
    Five
    Yes when I shutdown it will randomly turn on with memory loss
     
  13. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    11,490
    14,095
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    Unless you actually test it, you're just assuming that's not it; you don't know it. New batteries have been known to not be charged up or even be defective. But by now, unless it's defective, normal driving should have brought it up to a normal charge. But I'd still check it if it was mine.