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Dead 2012 Prius Plugin, NOT 12V battery?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by tcruzin, Jul 30, 2024 at 8:21 AM.

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  1. tcruzin

    tcruzin New Member

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    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Hi:

    I have a 2012 Prius Plugin 180K miles, no known problems. Yesterday I started it to leave work and it ran for maybe 2 seconds, then went completely dead - no power at all (lights, door locks, etc). Tried to jump with a battery booster - no effect.

    Returned this morning to check the 12V battery - initially it read 4.6V, so figured I would need to replace, based on other posts here. Removed the positive terminal connection and went to the negative and found it quite warm - hot even. Left the car to check with a dealership about whether this was likely a battery replacement or something else (they of course said tow it in). Returned to the car 30 min. later - positive terminal still disconnected, negative connected - but it was no longer warm. tested the battery again - read >12V. reconnect the positive terminal to car - decreases to ~6 volts.

    So the battery seems good but I'm guessing there is a short somewhere> Negative connection to cable and cable to body looks very sound.

    Any suggestions to diagnose further, or should I have it towed in?

    Great forum, by the way.- I've used it often.

    Thanks
     
    #1 tcruzin, Jul 30, 2024 at 8:21 AM
  2. Brian1954

    Brian1954 Active Member

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    Location:
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    Vehicle:
    2011 Prius
    Model:
    III
    Your 12v battery needs to be load tested. You could have a short inside the 12v battery.
     
    #2 Brian1954, Jul 30, 2024 at 9:28 PM
  3. BiomedO1

    BiomedO1 Senior Member

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    Location:
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    Vehicle:
    2021 Prius Prime
    Model:
    LE
    You've got a short someplace that's bypassing your fuse boxes - otherwise your fuses would've blown and the electrical short would've been limited to that circuit only.
    Unless you know how to do electrical work, it needs to be towed in or taken to an automotive electrical shop.

    If the battery itself was shorted, you wouldn't need the positive lead to be connected to complete the circuit. The negative post would've stayed warm. This doesn't mean that battery is still good. It needs to be recharged and tested.

    Good Luck...
     
    #3 BiomedO1, Jul 30, 2024 at 11:55 PM
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