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FIXED - P LOCK MALFUNCTION WHEN PARKING, PARK IN FLAT PLACE AND APPLY PARKING BRAKE SECURELY

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Phil Moffett, Jul 3, 2020.

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  1. Phil Moffett

    Phil Moffett New Member

    Joined:
    Jul 3, 2020
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    Location:
    Louisville, KY
    Vehicle:
    2010 Prius
    Model:
    III
    I have a 2010 Gen 3 Prius with this error message. Tried several things I found on the net, none of which worked. It appeared to me the car did not believe the car was in Park so it would not let me put the car in gear or have the gas or electric motor engage.

    Stumbled across this fix:

    1. Removed the negative cable from the 12V battery in the rear of the vehicle. Mine happened to be off all night because I got tired of trying to figure this out and went to bed. I put the negative cable back on the battery the next morning. I'm not even sure if this step is necessary or it leaving the cable off for a couple of minutes would accomplish the same results.
    2. With key fob in car, I pressed to Power button twice (with my foot OFF the brake).
    3. I shifted the car into Neutral (foot stil OFF the brake. I was on a flat surface).
    4. I pushed the Park button. The display showed I was in Park!!
    5. I place my foot on the brake, pushed the Power button firmly and it started normally. The error message cleared and I was on my way.

    I hope this works for you. I stumbled across this trying to get the car in Neutral so I could stage it for a tow truck ride to a mechanic. After I got it in Neutral, I figured what the hell, let's see if I can get it in Park. Yahtzee! Better to be lucky than good sometimes.
     
    #1 Phil Moffett, Jul 3, 2020
    Sunseeker, tacopyro, 2012 Prius v wagon 3 and 2 others like this.
  2. bisco

    bisco cookie crumbler

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    2012 Prius Plug-in
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    Plug-in Base
    i wonder what would have happened if you just tried to make ready after disconnecting the 12v.
     
    #2 bisco, Jul 3, 2020
    jerrymildred likes this.
  3. ASRDogman

    ASRDogman Senior Member

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    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    Until your luck runs out. :)
    You will probably have that problem again, soon.
    It's been a few months but someone else had that problem.
    You'll have to do a search here see how it was resolved. I believe it was the parking gear.
    I believe it was easy to replace.

    But, check the 12 volt battery. How old is it? The park lock gear is controlled by the
    12 volt battery. It it's low, you'll start getting strange errors and problems.

     
    #3 ASRDogman, Jul 3, 2020
  4. tacopyro

    tacopyro Member

    Joined:
    Oct 25, 2018
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    Location:
    Los Angeles
    Vehicle:
    2012 Prius
    Model:
    II
    My wife had the P Lock Malfunction as she got home from work today. she drove up to the driveway to open the gate as she has done so a hundred times in the last 8 months or so but today, when she pressed the P button, it just suddenly popped up. yellow triangle, notification, noise and all..

    She called me to come out to fix it, opened the gate (its manual) drove in and i checked to see what could be wrong.
    its like what happened to me when i was putting together my prius in January, my hybrid battery was bad. except, in her case, it cant be because of a weak or dead 12v or HV battery... everything looks good...

    So i figure its because of something that caused the pawl of the parking lock in the transmission not to go in as it should. i had watched Dr John Kelly describe it in his youtube channel. it has a spring that holds it when it falls in place. videolink

    We tried to push P, doesnt work of course. We tried it with
    the Ebrake, nothing.
    the EBrake and shifted to N. nothing.
    No EBrake and shifted to N while i rocked the car fwd and back. nothing.
    so i pushed the Power button to turn off the vehicle. it wont turn off with a quick push but a long push did.

    i rocked the car forward and back a few inches one more time.
    When we turned it on. i heard the parking pawl noise. the P light was on. but when we pushed it, the light turned off again. Malfunction still showing. so we did the above sequence again except the rocking until we turned it off.

    While off, i rocked it again. and this time, i felt the pawl was in position, it wouldnt let me rock it as much as it used to. We then tried turning the car on and it was now back to normal.

    This all happened around 5 mins of elapse time.

    No idea how this happened. FSM shows the Trans ECU is suppose to know exactly when to trigger the Pawl. i guess it missed by a fraction this time.

    Hope that helps someone.
     
    #4 tacopyro, Mar 2, 2021
    burebista likes this.
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