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2008 Prius ODDLY not starting

Discussion in 'Gen 2 Prius Technical Discussion' started by David G., Apr 3, 2018.

  1. David G.

    David G. New Member

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    2008 Prius
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    Hi All, First time poster. I have read through and found several "not starting" posts, but none are quite like mine (I think).

    My 2008 Prius will regularly (about every 2-3 months) NOT START. It would appear to be totally dead, no lights, no dash, can't unlock the doors, nothing. I would jump it and it would be fine and work another 2-3 months without issue before mysteriously not starting once again. This has happened consistently 4 times over the past year.

    This last time, it was dead in my driveway and I jumped it, took it to TOYOTA and had the 12v battery checked. It came back in great health and nearly fully charged (not by my driving there unless the battery recharges within 10 minutes of driving). I'm not thinking it's the battery and the dealership hasn't heard of symptoms like this. The car is used regularly (doesn't sit for more than a day), the battery seems to be fine, yet, every few months it needs a jump to get rebooted.

    It's almost acting like when you get a bad spot in a starter, but, I would think it would be more random and more frequent if it were. Could there be something in the computer system that regularly just wants to kill the car? A bad sensor that complains about it's job only quarterly? The timing is almost too perfect to be coincidence.

    I wanted to see of anyone else has experienced this before I begin to sink money into diagnostic tests that probably won't show anything. Any ideas?

    Thank you in advance,
    David G.
     
  2. AzWxGuy

    AzWxGuy Weather Guy

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    My first thought is back to the 12V battery. That is one of many possible failure modes for typical 12V batteries, intermittent as it is. It would help to know the age of the battery. Getting codes read might help also, but there might not be any related to this problem. What would really help is the next time it does this to pop the hood and put a meter on the jump point in the fuse box and see what voltage you read there. Check the integrity of the 12 volt wiring path that is visible to you back in the rear passenger side corner, both battery posts clean and tight, a good connection on the body side negative cable. I can't think of anything else that might cause this.
     
    SFO and bisco like this.
  3. bisco

    bisco cookie crumbler

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    welcome!

    agreed. if you're here asking questions, get a multimeter and prove to yourself that the 12v is good.
    check it in the morning before turning anything on.
    how old is the battery?
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    What would really help is the next time it does this to pop the hood and put a meter on the jump point in the fuse box and see what voltage you read there.

    x2

    Odds seem good to me that you'll find no power at the jump point.
     
  5. sjguy

    sjguy Junior Member

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    David G., from what I've read, some of your symptoms may occur with a bad combination meter. There's a sticky thread on the maintenance and troubleshooting forum for repairing it.