STRANGE Behavior when Turned Off - Help Needed - 2005 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by GregAZ, Jan 11, 2010.

  1. GregAZ

    GregAZ Junior Member

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    So, my 2005 Prius with 120kMi (all my miles) is finally starting to give me some issues .... the latest one is this:

    When I turn off the car, the Check Engine light comes on really faint, and it starts making a beep sound. The car is DEAD at this point, I can't turn it on, I can't lock it, can't do ANYTHING. Then after a while it comes back ON (all on it's own) and it's almost like it's booting. Then I can turn it off and lock it. When I come back, it opens and starts right up. The batteries have never been replaced, and the car is otherwise sound (few niggles that will need to be addressed at the 120kMi service (also needs a new driver side headlight ($700!!!!!))).

    Any ideas on what this can be? Many thanks in advance!
     
    #1 GregAZ, Jan 11, 2010
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I'd suggest that you start by replacing the 12V auxiliary battery. It's possible that you might have another issue, but the battery is a good place to start.
     
    #2 Patrick Wong, Jan 11, 2010
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  3. Ophbalance

    Ophbalance Member

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    What's a good unloaded range for the 12V, specifically for the Prius? I'm seeing 12.1 with the car totally shutdown on the scanguage... but I would expect to see some of these odd issues if that were truly the case.
     
    #3 Ophbalance, Jan 11, 2010
  4. GregAZ

    GregAZ Junior Member

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    Forgive the question, but is that hard to do? I am not a total mechanical dufus, just spoiled by the Prius. I have replaced engines in other cars before, but don't even know where the aux battery in the Prius is! I assume this is something I can do myself?
     
    #4 GregAZ, Jan 11, 2010
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    A new 12V AGM battery fully-charged will measure 12.8-12.9V. 11.9V is discharged. If your Scan Gauge is measuring voltage accurately, then your battery is ~30% charged. The voltage measurement is valid only if the car has been IG-OFF for several hours, prior to measurement.
    Hi Greg,

    The 12V battery is in the hatch, right rear corner. Yes, you can DIY. Remove the traction battery ventilation duct that runs over the 12V battery, and the brake power supply next to the 12V battery, to improve your access to the 12V battery.
     
    #5 Patrick Wong, Jan 11, 2010
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  6. Ophbalance

    Ophbalance Member

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    Crap... that's what I thought. I'll have to pull that panel off this week and see what it's reading on the multimeter... unless the post on the front of the car is accurate enough? This'll be the second optima that I'll have bought this year.:rolleyes:
     
    #6 Ophbalance, Jan 11, 2010
  7. GregAZ

    GregAZ Junior Member

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    You can put an Optima in the Prius?? Is this recommended? I used Optimas in many other cars and LOVE them!
     
    #7 GregAZ, Jan 11, 2010
  8. Ophbalance

    Ophbalance Member

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    #8 Ophbalance, Jan 11, 2010
  9. richard schumacher

    richard schumacher shortbus driver

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    The jump post value will be close enough to the battery terminal value unless the car has some abnormal current drain somewhere (in which case the jump value would be even lower, which would be a good thing to discover).

    The Optima does need adaptation. eLearnaid sells a complete kit for this, very nice.
     
    #9 richard schumacher, Jan 11, 2010
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  10. KadensGma

    KadensGma New Member

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    I have an 05 Prius and when I started to have " strange glitchy electrical " it turned out to be the 12 volt battery.....simply wasn't recharging up fully...oh I have 133,000 miles hope to replace next October with another one..
     
    #10 KadensGma, Jan 12, 2010
  11. GregAZ

    GregAZ Junior Member

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    Thank you, everyone. Had to jump start it this AM, and when at the dealer, it was discovered that the 12V battery is indeed toast. $150 and my Toyota reliability is BACK! You forget how much you get used to it, until you no longer have it. :)
     
    #11 GregAZ, Jan 12, 2010
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