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

09 prius turns back on after turning it off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Eunhon, Aug 26, 2020.

  1. Eunhon

    Eunhon Junior Member

    Joined:
    May 13, 2019
    5
    0
    0
    Location:
    Florida
    Vehicle:
    2009 Prius
    Model:
    N/A
    So my prius started doing this 3 weeks ago. I would turn it off and then sometimes itll turn itself back on in accessory mode. One time i turned it off and sat in the car for like 10 minutes, it turned it self back on. Doesnt happen every time but it does happen often enough its messing up stuff like resetting my miles meter in the energy monitor and sometimes itll turn off my AC when it turns it self back on. Heres a video


     
    #1 Eunhon, Aug 26, 2020
    Last edited by a moderator: Aug 26, 2020
  2. valde3

    valde3 Senior Member

    Joined:
    Jun 28, 2014
    2,002
    745
    0
    Location:
    Finland
    Vehicle:
    2004 Prius
    Try to turn off the smart key system and only use the key in the slot. If you take the key out it can't turn back on? So it's just peeping? Or does it still turn back to ign-on?
     
    #2 valde3, Aug 27, 2020
    SFO likes this.
  3. Diemaster

    Diemaster Active Member

    Joined:
    Oct 31, 2017
    290
    260
    2
    Location:
    so. cal
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Just a guess. The power button is physically or electrically sticking. So it thinks your holding the button down?
     
    #3 Diemaster, Aug 27, 2020
  4. valde3

    valde3 Senior Member

    Joined:
    Jun 28, 2014
    2,002
    745
    0
    Location:
    Finland
    Vehicle:
    2004 Prius
    Basically what the test on my previous post is testing. If control unit sees the button pressed without the key in it peeps. If it's a problem with relay control unit etc. it will still power on.
     
    #4 valde3, Aug 27, 2020
  5. Steve Lavsa

    Steve Lavsa New Member

    Joined:
    Apr 27, 2022
    4
    0
    0
    Location:
    pe
    Vehicle:
    2007 Prius
    Model:
    Base
    Mines doing same thing there has been a bunch of posts about this with no confirmed resolutions so I'm bringing them back from the dead. Did you ever figure out what was going on? turn it off, and it turns back on and climate, clock, odometers reset.
     
    #5 Steve Lavsa, Apr 27, 2022
  6. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,501
    3,767
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Your issue sounds like a 12 V power supply issue to me, in that the power is intermittently going on and off. Check all the connections at the 12 V battery in the back. All three (the positive connection on the battery, the negative on the battery, and the ground connection to the car body) should be clean (free of all corrosion) and tight.

    Check that out and post back if there is no change.
     
    #6 dolj, Apr 27, 2022
  7. Qinti

    Qinti New Member

    Joined:
    Jan 9, 2024
    3
    0
    0
    Location:
    Hawaii
    Vehicle:
    2009 Prius
    Model:
    Two
    Im wondering what happened, did you figure it out? Was it the 12v? My 09 lately started doing the same thing, but my 12v is brand new and checked and works fine. Right now, im locked out of my trunk and cant even reach the 12v...the car is completely dead.
     
    #7 Qinti, Feb 12, 2024
(You must log in or sign up to post here.)