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2012 Push to Start, Dead, Remove Ground from 12v, Starts

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MikeySG84, Jun 12, 2018.

  1. MikeySG84

    MikeySG84 New Member

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    My wife has a 2012 Prius that has recently started showing odd issues out of nowhere. One day, wouldn't crank. Jumped, ran for two days, dies. See loose ground, clean terminal connector, cranks. Cranks next morning, dies that evening. Remove ground for 3-5min, cranks.

    This sounds to me to be an ECM reset of sorts where this is enough time to drain the capacitors to allow the car to reset and start. It does not throw a CEL or any standard warnings.

    Where do I need to trouble shoot from here? Want to not have to deal with disconnecting and reconnecting everyday :D
     
    #1 MikeySG84, Jun 12, 2018
  2. Grit

    Grit Senior Member

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    ALL signs that 12v bat needs to be replaced.
     
    #2 Grit, Jun 13, 2018
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  3. MikeySG84

    MikeySG84 New Member

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    AGM battery test showed as good as well as load testing. Still battery?
     
    #3 MikeySG84, Jun 13, 2018
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    At the least check the voltage with a multimeter. Jump starting and expecting it to be good is a fool's paradise.

    (@grid may have to change his signature now...)
     
    #4 Mendel Leisk, Jun 13, 2018
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  5. MikeySG84

    MikeySG84 New Member

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    Completely agreed, but the car will crank right up after 5 minutes of having ground removed. That along with the battery being checked for CCA at 325 and voltage correct, I'm kinda at a loss right now...

    Only temptation is to get a battery and see if issue is resolved over next week.
     
    #5 MikeySG84, Jun 13, 2018
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  6. bisco

    bisco cookie crumbler

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    is the battery 6 years old?

    btw, the 12v doesn't crank anything, just powers up computers and relays. doesn't take much for it to mess with the computers minds.:cool:
     
    #6 bisco, Jun 13, 2018
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  7. MikeySG84

    MikeySG84 New Member

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    You'd be correct... I'm not disagreeing with it being the 12v, just haven't worked on a Prius, ever.
     
    #7 MikeySG84, Jun 13, 2018
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  8. Grit

    Grit Senior Member

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    I'll change signature when I get home from work. Usually on the mobile phone browser and don't see the signature.
     
    #8 Grit, Jun 13, 2018
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  9. bisco

    bisco cookie crumbler

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    stinky expensive little battery that has caused more angst over 14 years than any other single prius part.:p
     
    #9 bisco, Jun 13, 2018
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Ok. Mystery then.
     
    #10 Mendel Leisk, Jun 13, 2018
  11. bisco

    bisco cookie crumbler

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    ah, but is the voltage correct? if it is 12.5 or better after having been off for 8 hours, then i would read the trouble codes. disconnecting the a good battery to make the car start again usually means trouble somewhere else.
    what dash lights have you gotten?
     
    #11 bisco, Jun 13, 2018
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