/!\ Caution The transmission P lock mechanism is abnormal

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by goldfinger, Jul 17, 2015.

  1. goldfinger

    goldfinger Active Member

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    OK, next problem. I've been getting the message /!\ Caution The transmission P lock mechanism is abnormal. Park your car at a flat place, and apply the parking brake completely. Are you sure? I could just jump out now.

    This message comes in waves with a beep and heart stopping red triangle. The car drives fine and the message is gone after a restart. I've had 2 episodes over the last few weeks.

    The parking pawl appears to hold the car on mild grades. I always use the parking brake out of habit, so the transmission has never been abused.

    Hooked a multimeter to my battery and have monitored for a few days. Here are the values after sitting overnight. These seem OK. I have 2 year old Optima DS46B24R.
    • Off. 12.58v
    • Push once. 12.26v
    • Foot on brake push again 13.94v
    Also, The inverter coolant pump is humming and producing a good flow in the reservoir.

    What can I check next?
    IMG_0069.JPG
     
    #1 goldfinger, Jul 17, 2015
  2. bisco

    bisco cookie crumbler

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    hatch not shut tight?
     
    #2 bisco, Jul 17, 2015
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Usually a weak 12V battery causes that symptom. However your voltage readings are pretty good and the DC/DC converter is working given your measurement of 13.9V when READY. So I think you should just live with the problem for now and see what happens.
     
    #3 Patrick Wong, Jul 17, 2015
  4. uart

    uart Senior Member

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    Check the 12V again at the front jumper terminal (to any good clean metal ground point). Try it with the headlights or parking lights on. This will test that it's not a bad connection somewhere.
     
    #4 uart, Jul 18, 2015
  5. goldfinger

    goldfinger Active Member

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    uart, I checked the voltage differential between the battery and cigarette lighter. With lights and radio on in accessory mode I measured 188mV. Lights off 56mV. This seems acceptable to me, but you might have something. I may have disturbed the battery connections when I pulled the plastic cover off the top. I'll clean and dress the terminals.
     
    #5 goldfinger, Jul 18, 2015
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Isn't it nuts, that dash warnings typically have not the slightest connection to the actual problem?
     
    #6 Mendel Leisk, Jul 18, 2015
  7. CR94

    CR94 Senior Member

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    Like beeping and "KEY DETECTED IN CAR" suddenly popping up, whilst driving with the key safely inside car?
     
    #7 CR94, Jul 18, 2015
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Well it's true. :ROFLMAO:
     
    #8 Mendel Leisk, Jul 18, 2015
  9. uart

    uart Senior Member

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    Yeah that's all good, but it doesn't check the ground connection. If you measure from the jump terminal to chassis (with the lights on) then it confirms connections on both sides of the battery!
     
    #9 uart, Jul 19, 2015
  10. goldfinger

    goldfinger Active Member

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    With lights and radio in accessory mode I measure 3.8 mV from the battery negative center of post to the chassis. Again I may have disturbed things in my previous measurement activities. I still plan to dress the terminals. I know I have some red grease somewhere, but I'll probably have to buy it again.
    IMG_20150719_141345~2.jpg
     
    #10 goldfinger, Jul 19, 2015
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    /!\

    Just had to try that. :)
     
    #11 Mendel Leisk, Jul 19, 2015
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    That sounds pretty good to me.
     
    #12 Patrick Wong, Jul 19, 2015
  13. goldfinger

    goldfinger Active Member

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    #13 goldfinger, Oct 18, 2015
  14. Ahmed Mahmoud

    Ahmed Mahmoud Junior Member

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    I had this happen recently, after taking it to the dealer and following a step by step check procedure, it was the Engine ECU that needed to be repaced, they repaced with a used one, used ones starts at $20 on ebay.
     
    #14 Ahmed Mahmoud, Oct 14, 2017
  15. Chris Holley

    Chris Holley Junior Member

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    I've had this same intermittent issue for over 100,000 miles. It's a 2005 and it runs fine. We maxed out the odometer at 299,999 four years back. We're on the original HV battery. Like Goldfinger, this only happens in rainy weather which leads me to suspect it's not an ECU issue. Any suggestions?
     
    #15 Chris Holley, Nov 5, 2019
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