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

08 Prius intermittently won't start seems to be more frequent

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JWil, Apr 3, 2023.

  1. JWil

    JWil New Member

    Joined:
    Apr 3, 2023
    2
    0
    0
    Location:
    Midwest
    Vehicle:
    2008 Prius
    Model:
    Three
    08 Prius will not start… acts as if it is dead. Normally when this happens it will easily jump start. It does not seem to need to be charged by driving. Typically after jump, you can drive a few blocks turn it off and it starts right up. however later...even after continued driving it will not start again, and need to be jumped.
    Sometimes key will lock in slot so you cannot take it out. My fix is to hold the power and the control Button in at the same time for about 10 seconds and then it seems to release the key.
    I have gotten the transmission lock emergency brake warning that says there is an issue is from being parked on an incline which locks the gear in park and if lucky neutral... but i cannot put the car into reverse or drive. Sometimes I take the key out, use the remote to unlock the doors lock the doors power it on, and then somehow it takes it out of park. ... If I can get it into neutral, i can push it to where it's not on an incline and try to start it again this does not always fix it so then I do the same with turn it off turn it on unlock the doors using the key fob remote and lock the doors using the remote…. eventually it seems to reboot and allow me to put it into drive or reverse
    Don't know if there is a bad fuse.
    Hybrid system warning light first time April 2nd 2023...It was on temporarily turned on then went off starting car up, and pushing remote for locks, and turning off a few times...after “reboot “ was successful?
    Do you think this indicates an issue with Hybrid system…or was it maybe a temporary fluke?
    Also, different issue:
    it is difficult to get most of the jumper cables, especially the square head jumper cables to fit or grip onto the small screw under the red post cover to clip on… is there a way to do an extension that will still fit under that red post cover? Any better idea?
     
    #1 JWil, Apr 3, 2023
  2. Stevewoods

    Stevewoods Senior Member

    Joined:
    Jun 10, 2014
    647
    983
    0
    Location:
    Seattle, WA
    Vehicle:
    2008 Prius
    Model:
    II
    Gosh, does this say need new 12-volt battery?

    How old is the current 12-volt? If you don't know, well that tells you something.

    Just because it works after running for a bit does not mean it is still a properly functioning battery.

    Yes, my highly valued opinion, which is worth just what you paid for it -- You need a new 12-volt. Not a new hybrid.

    Cost: right around $200. Installed would be right around $90 more, although I would do it for $40, plus travel expenses. :)
     
    #2 Stevewoods, Apr 3, 2023
    JWil likes this.
  3. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    8,134
    1,410
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You need to verify that you're 12 volt system throughout the vehicle is working headlights do you have HID lights are you a tourer model? Everything in the car work your internal display speedometer gas gauge and all that working fine? The 12 volt is always suspect to the no start and always needing a jump That's the first thing you need to be looking at The battery needs to pass a load test and be really holding 12 volts for hours The car hasn't aftermarket stereo or anything's plugged up to it are they left plugged up all the time draining or putting a load?
     
    #3 Tombukt2, Apr 3, 2023
    JWil likes this.
  4. Stevewoods

    Stevewoods Senior Member

    Joined:
    Jun 10, 2014
    647
    983
    0
    Location:
    Seattle, WA
    Vehicle:
    2008 Prius
    Model:
    II
    #4 Stevewoods, Apr 3, 2023
  5. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,254
    1,359
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    IF the 12V battery was in decent condition, it would take 6-12+ hours to properly charge it to full capacity. Then have it load tested to verify it's condition.

    Assuming your 12V is age unknown (likely old) and has been discharged many times, then I would recommend replacing it and see what you have afterward.

    There might be additional faults with the hybrid system, but you have to "cover the basics" first (which includes having a proper 12V supply).

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Apr 3, 2023
    JWil likes this.
  6. JWil

    JWil New Member

    Joined:
    Apr 3, 2023
    2
    0
    0
    Location:
    Midwest
    Vehicle:
    2008 Prius
    Model:
    Three

    Thanks I'll try to get a thorough test on the battery today, and will ask about holding 12 Volts for hours
     
    #6 JWil, Apr 4, 2023
  7. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    7,035
    2,783
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Good advice so far.
    The other common cause is a loose or corroded main battery cable.
    The OTHER end of the negative cable where it connects to the frame or body is often the culprit.
     
    #7 sam spade 2, Apr 4, 2023
(You must log in or sign up to post here.)