HELP! park gear slips out a few seconds after shutoff!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Kyle McDowell, May 4, 2018.

  1. Kyle McDowell

    Kyle McDowell Junior Member

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    2009 gen2 prius. sometimes has the p lock thing-this video should tell you all that you need to know.

     
  2. bisco

    bisco cookie crumbler

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    how is the 12v health?
     
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  3. jerrymildred

    jerrymildred Senior Member

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    That's the 1st thing I'd check.

    BTW, iirc, you mentioned a parking brake pump? There is no parking brake pump. There is a brake pump, though, which I suppose could sound funky if it wasn't getting full voltage.
     
  4. dolj

    dolj Senior Member

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    The noise you pointed out is the coolant control valve. You may have more than one thing going on here.

    Have you scanned the car for codes?

    From what I was able to see in the video (not easy), it looks like you have at least 2 dashboard lights on, meaning there are codes to be pulled.

    Get those codes and the solution will be more focused.

    Also +1 to checking the 12 V battery. Replace that first if it is in poor condition.
     
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  5. WilDavis

    WilDavis Senior Member

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    Welcome to PriusChat! First things, first: exactly what are you trying to do? The only thing I really noticed about your video, is that I felt rather queasy after all the "wobble-cam" :eek:, that… …and the fact that your nail-polish doesn't really go with the fire-engine red of your 2009 Gen II, …er, that's it! …sorry I couldn't be of more help! :rolleyes:;)
     
  6. Kyle McDowell

    Kyle McDowell Junior Member

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    I said motor. it's (I think) the p lock motor. it's (again, i think) connected to the P CON MAIN FUSE.
     
  7. bisco

    bisco cookie crumbler

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    this thread?
     
  8. bisco

    bisco cookie crumbler

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    could be the p lock motor. how many miles on her?
     
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  9. ChapmanF

    ChapmanF Senior Member

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    This issue is really just waiting to be diagnosed in the old fashioned way (just to be clear, by "old-fashioned" I don't mean "ignoring the computer", I just mean "get the relevant information and go down the possibilities, checking them out"). In this case, reading the codes from the "transmission control ecu" should give you a lot of the relevant information.

    It's possible you've got something that's mechanical, at least in part. The parking pawl is not something that only gets moved in and out of position by the actuator motor. There is a stout mechanical detent spring built into the mechanism so that it snaps securely into the parked or not-parked position. You can see that on pages HX-82 and HX-99 of the repair manual (I'm looking in a 2006 edition, '09 page numbers could have moved a bit). You should be able to take the actuator motor completely off and still not have the linkage inside the tranny easily "slip" from one position to the other. (You would probably need a pretty long handle just to turn that shaft from either position to the other by hand, with the motor removed.)

    So if it is able to hold the car from rolling but then pop/slip out of position with the power off, it must never be getting all the way to the parked position in the first place (where the spring would snap it in place), but only far enough for the pawl to barely engage.

    That would be consistent with the transmission control ECU blinking the status light at you and repeatedly trying to move it fully into position because it knows it isn't there yet.

    That might mean there's something mechanical, internal to the tranny, that is blocking the linkage from getting all the way to park. The parking actuator motor is not some light-duty piece of gear. (For a sense of that, page HX-44 says it has to draw 50 amps before the ECU will set an excess-current code, and 50 amps at 12 volts is almost a horsepower. The clever flat cycloid gear that's built in multiplies its torque by 61). So if the linkage inside the tranny can be moved, the actuator motor is probably going to move it. :)

    Now, when you read the codes, you might see some about inadequate power reaching the ECU and actuator, so that could also be a cause of insufficient torque to fully move the linkage. When interpreting the codes, keep in mind that anything they say about voltage is talking about voltage measured at the transmission control ECU, not back at the battery, so some fault in wiring or connections on the way to the ECU and motor would be as likely to explain it as a problem with the aux battery per se. This is especially true if you see it having problems completing the shift even when the car is in READY, because then you've got full converter voltage regardless of the battery condition, and if the readings are still low at the transmission control ECU, that's a strong suggestion of a wiring issue.

    Or, maybe there's mechanical wear within the actuator itself. At least that'd be an easier repair.

    Anyway, it's the trouble codes you read from that ECU that will give us the starting direction down that troubleshooting tree.

    -Chap
     
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