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P Lock malfunction at specific times

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by RedQueen, Jun 18, 2018.

  1. RedQueen

    RedQueen New Member

    Joined:
    Jun 18, 2018
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    Location:
    Florida
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I bought a used 2012 PIP 2 months ago (118k miles) and I have noticed instances of P Lock malfunctions occurring. The 1st situation is when the car has been parked for a while like all day at work, 8.5 hrs, then when I leave if I turn the a/c on and the fan speed is set close to or at highest setting the malfunction will occur. This doesn't seem to happen if I have driven the car around 20 minutes then turn the fan speed to high.

    The 2nd situation when it occurs is when driving at night and I turn on the high beams. It doesn't matter how long I have driven the car, as soon as those high beams go on it throws the P Lock. I actually just discovered this scenario the other night coming home late as I don't usually drive at night and when I do it is early enough for there to be too much traffic to use the high beams.

    I suspect the 12 v is the original one but I am not sure on that. Should I try replacing it and see if that fixes the problem or take it in to Toyota? I would hate to spend the mucho $$ that the dealership would charge if it's something simple. Any help would be appreciated!
     
  2. Pluggo

    Pluggo Senior Member

    Joined:
    May 23, 2016
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    Location:
    Folsom, Pennsylvania
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Advanced
    Congratulations and welcome! I think you're on the right track for suspecting the 12v battery. They are not supposed to last 6 years, but the PIP is very good at concealing a weak one since these do not generally play the role of a starting battery, and every time you plug in for a charge, the 12v gets a charge, too. There finally comes a point in time where even a daily charge like this won't be enough. If you can determine your 12v is original, then it is certainly time to replace it. The product of choice seems to be the Optimus DS46B24R yellow top deep cycle battery.
     
    jerrymildred likes this.
  3. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
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    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    Sounds like the 12V to me, too. The P lock is sometimes and early warning sign. If your battery lasted that long here in FL, that's remarkable even for a Prius. Easy enough to make a basic check of the condition. Let it set overnight without charging the traction battery. In the morning, open the right front door (to hopefully keep the brake pump from running), reach across and pop the hood. Check the aux battery voltage at the jump point under the fuse box cover. If it's under about 12.5V, that's not good.

    I hear lots of good reports about the Optimus batteries. I've always stuck with the Toyota OEM batteries.
     
    QuantumFireball likes this.
  4. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    congrats and welcome!

    are you capable of diy?