2007 Prius won't light up

Discussion in 'Gen 2 Prius Technical Discussion' started by SBP Mike, Apr 24, 2025.

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  1. SBP Mike

    SBP Mike Junior Member

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    I bought a dead prius recently. When I towed it home I was able to boost it into the Park or Neutral mode with a spare battery, jumper cables and a battery jumper device. I took a while, but it finally worked. That saved me needing to pull it up on the dolly in Park mode. It rolled off the car dolly still in neutral at home so I could move it to a convenient shade tree spot. I have been working on it off and on (busy lives, right) for a couple of months and have not been able to get it to light up the dash again. I put a charger on the traction battery for a couple of hours and it now reads 209v. I have charged a few 12v batteries and connected them up, but no joy. I can't get any dash lights. I can't even get the little red light that usually appears on the dash when you reconnect a 12v battery. I have gone back to the setup that worked when I loaded it up with a booster box that cranks out over 16v, but that has not give me any dash lights. I have heard the coolant recovery pump run during an apparent attempt to boot or shut down, but that's it.

    So... any suggestions on how to proceed? I think a reading of 209 on the traction battery indicates enough charge on that system, but I am not sure. I think will put a charger back on the traction battery for an hour or two to put a little more charge in it.

    I am mulling pulling the 12v battery out of my daily driver prius and swapping it in to the dead one as means to rule out a problem with the 12v system. That's seems ridiculous when I am about to connect the 16v booster box, but I might do it anyway.

    Thanks in advance for any ideas.

    Mike
     
    #1 SBP Mike, Apr 24, 2025
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  2. PriusCamper

    PriusCamper Senior Member

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    Hi Mike, Have a bit more patience with charge and balance of pack... You'll want at least 24 hours with cooling fan running full blast to get an old pack healthy with 1/3 amp w/250v DC or greater charger. Of course that's probably not the cause of the dead dash. Have you checked the AM2 fuse on the fuse box in engine compartment?
     
    #2 PriusCamper, Apr 24, 2025
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  3. SBP Mike

    SBP Mike Junior Member

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    will check the AM2 fuse. then will go back to charge on traction battery with a little more patience and with cooling fan running fullblast

    Thanks

    Mike
     
    #3 SBP Mike, Apr 24, 2025
  4. bisco

    bisco cookie crumbler

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    maybe some other fuse as well. are you getting close to 13 volts at the jump point under the hood?
     
    #4 bisco, Apr 24, 2025
  5. MAX2

    MAX2 Senior Member

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    The small red indicator - do you mean the immobilizer icon? Do you have a car with a smart key fob that lies in your pocket and turns on the car without inserting it into the slot?

    In the event that the car has been standing for a long time, the key fob has also been lying somewhere for a long time and the battery in it could have died.

    Check the battery in the key fob and replace it if it does not work.
     
    #5 MAX2, Apr 25, 2025
  6. SBP Mike

    SBP Mike Junior Member

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    AM2 is good. Thanks for suggestion to look at that

    I will find time over the next few days to get in a lot of charge and check time on the batteries.
     
    #6 SBP Mike, Apr 25, 2025
  7. SBP Mike

    SBP Mike Junior Member

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    Not a smart key fob. I replaced the battery in the fob. No joy, but I do see bright red light on the fob when I push the buttons, so I think the fob is fine. I am guessing from your question that I should not expect to see the immobilizer red light on the dash. Thanks for those tips and ideals
     
    #7 SBP Mike, Apr 25, 2025
  8. SBP Mike

    SBP Mike Junior Member

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    12.52 volts front and back
    I don't think that's enough oomph to fire up the computer.
    220 volts on the traction battery. I have not started checking individual modules to look for bad ones. I usually do that after I get the vehicle to light up and move. And then I use Dr Prius as my first tool to see how the traction battery looks
     
    #8 SBP Mike, Apr 25, 2025
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  9. SBP Mike

    SBP Mike Junior Member

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    12.52v front and back. I think I will start pulling fuses and checking each one
     
    #9 SBP Mike, Apr 25, 2025
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  10. Skiddmore

    Skiddmore Junior Member

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    Just this morning my car, that has a smart key fob, would not unlock until I pulled the fob out and pushed the unlock button.
    Then the dash would not light up until the fob was inserted into that hole in the dash. I am happy that it did start up.
     
    #10 Skiddmore, Apr 25, 2025
  11. bisco

    bisco cookie crumbler

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    might need a battery
     
    #11 bisco, Apr 25, 2025
  12. Skiddmore

    Skiddmore Junior Member

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    I lost my miniature phillips.
     
    #12 Skiddmore, Apr 25, 2025
  13. bisco

    bisco cookie crumbler

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    the fob opens without tools
     
    #13 bisco, Apr 25, 2025
  14. bisco

    bisco cookie crumbler

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    #14 bisco, Apr 25, 2025
  15. Skiddmore

    Skiddmore Junior Member

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    On my fob once open a mini phillips is needed. The old battery voltage was 3.07 new battery voltage is3.3.
    I still need to push a button to unlock the doors and also place the fob in the dash before the power button will light up the dash. Something to learn aout.
     
    #15 Skiddmore, Apr 25, 2025
  16. dolj

    dolj Senior Member

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    Au contraire, that is more than enough oomph. You have got other things going on.
    Have you pressed the "Key" button to the IN position by any chance? That disables the SKS function, and from your description it sounds like your SKS is disabled. You will find the "Key" button under the steering wheel at around knee height.
     
    #16 dolj, Apr 26, 2025
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  17. Skiddmore

    Skiddmore Junior Member

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    Thank you. Yes the Key button under the the column was the solution to my confusion.
     
    #17 Skiddmore, Apr 26, 2025
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  18. pasadena_commut

    pasadena_commut Senior Member

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    Probably. It is possible for a 12V battery to have so little capacity that its voltage collapses instantly when any load is applied, even though with no load it looks OK. Not very common though. Put one of the small electronic battery testers right on the battery terminals (NOT at the jump point) and it would settle this point.
     
    #18 pasadena_commut, Apr 26, 2025
  19. ChapmanF

    ChapmanF Senior Member

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    Toggling the KEY button under the dash and having the car work as expected also kind of settles things.
     
    #19 ChapmanF, Apr 26, 2025
  20. SBP Mike

    SBP Mike Junior Member

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    voltage dropped to 11.something during attempt to start by pushing the power button. I think you are correct with the idea that this 12v battery does not have sufficient capacity to start the car.
     
    #20 SBP Mike, Apr 27, 2025
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