1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Stopping the hybrid system in an emergency

Discussion in 'Gen 3 Prius Main Forum' started by datrays, Oct 6, 2009.

  1. datrays

    datrays New Member

    Joined:
    Oct 6, 2009
    39
    9
    0
    Location:
    Harrisburg, PA
    Vehicle:
    2010 Prius
    Model:
    III
    Due to the floor mat recall I was trying to research what the last ditch option was to get the prius turned off since there is no key if the accelerator was stuck. On page 167 of the manual I found out that if you hold the POWER button for three seconds it will turn off the hybrid system. Some questions if you push the power button:

    Will the steering wheel lock in place?
    How will this affect the brakes and/or steering?
    Is it safe to try this in an empty parking lot at low speeds?

    The Prius is my wife's car and I'm trying to give her an idea what to expect if she ever had to use this procedure.

    Thanks in advance,

    Stopping the hybrid system in an emergency
    If you want to stop the hybrid system in an emergency while driving the vehicle, push and hold the “POWER†switch for more than 3 seconds. However, do not touch the “POWER†switch while driving except in an emergency. If the hybrid system stops while the vehicle is being driven, this could lead to an unexpected accident.

     
    2 people like this.
  2. maledyris

    maledyris New Member

    Joined:
    Apr 28, 2009
    77
    11
    0
    Location:
    Burnaby, BC, Canada
    Vehicle:
    2010 Prius
    Model:
    N/A
    Instead of powering off, in an emergency I would recommend putting the car into neutral instead. I think it would be a lot safer because there would be no control lost.
     
    1 person likes this.
  3. datrays

    datrays New Member

    Joined:
    Oct 6, 2009
    39
    9
    0
    Location:
    Harrisburg, PA
    Vehicle:
    2010 Prius
    Model:
    III
    I agree getting it in neutral and getting it stopped would be the first thing to try but I believe it wouldn't be a bad idea to know what the next step if that doesn't work.

    In this article about the recent lexus crash they mention both putting it in neutral and the pushing the power button for 3 seconds.



    Toyota spokesman Brian Lyons told the Associated Press the driver could have turned off the car by holding its start button for three seconds. However, this would have resulted in a loss of power steering and power-assist to the brakes. Alternatively, the driver could have shifted the car to neutral when the unintended acceleration began. It’s unclear if some other problem prevented this from happening.
     
    1 person likes this.
  4. sciguy125

    sciguy125 Junior Member

    Joined:
    Jul 18, 2009
    90
    22
    0
    Location:
    CA
    Vehicle:
    2010 Prius
    Model:
    II
    Don't know. Does it lock when you turn off normally? I haven't tired. "Normal" cars have a mechanical lock that's tied to the key.

    Normal cars lose both power steering and power brakes. My understanding is that the Prius disconnects the master brake cylinder during normal operation, but fails safe. My guess (and expectation from the engineers) is that you regain manual control when you turn it off.

    Since it has electric power steering, I would expect to lose that too.

    I don't see why not. If I had a large enough open space it'd be wiling to try it. I suggest that it be done by a professional driver on a closed course.
     
    1 person likes this.
  5. garygid

    garygid Senior Member - Blizzard Pearl

    Joined:
    Aug 23, 2009
    379
    23
    0
    Location:
    Orange County, CA
    Vehicle:
    2010 Prius
    Model:
    III
    With a run-away, first get off the "gas" pedal and "stomp" the mechanical brake, and then quickly take the 2 sec to shift into N, and immediately take the additional 3 sec to force "OFF", being careful to maintain control of the steering.

    Of course a confused or "broken" ECU (computer) might ignore the "N" (and even the OFF), so the first "step" is the most important, I suspect.
     
    1 person likes this.
  6. tumbleweed

    tumbleweed Senior Member

    Joined:
    Oct 3, 2005
    4,067
    687
    0
    Location:
    Eastern Oregon
    Vehicle:
    2010 Prius
    Model:
    V
    I ask about the 3 second shut down in another thread. Mine will shut down almost immediately when I hit the power button while the car is standing still. I don't know what happens while the car is moving though, at least not with the gen3. I think everyone is a bit reluctant to try it because if you hit the power button while stopped it goes into park and no one wants to have that happen while moving.

    But I may work up the courage and give it a try, after all that's what warranties are for "honest, I don't know what happened I was just driving down the road and it made all these noises and came to a screeching halt".

    I did this (power button) with my gen2 about 3 years ago and it did not go into park, it went into neutral and shut down. No power steering but that's no problem it steers fine with out it, there was enough pressure in the accumulator for the brakes to work but if there were not no problem just push harder.

    What I don't remember is how long I had to hold the power button down, was it 3 seconds or did it just shut down? and I don't remember exactly how I had to restart it, hold the button down for several seconds I think for the restart.

    Anyway Neutral really does work just fine, it only takes 1 second. Using Neutral you still have power steering and power brakes also. I have tried that with the gen3, nothing to it. Put it in Neutral going down the highway at a speed of 40 or less, actually 46 or less so you don't over speed MG1, and try it. When you see it works just select D again and off you go.

    EDIT: Owner's Manual page 167 does say to hold the Power Switch in for 3 seconds to shut down the hybrid system while driving. But it also says you shouldn't do it except in an emergency because this could "lead to an unexpected accident". I guess the "unexpected" ones are the ones you have to watch out for.
     
    1 person likes this.
  7. wls

    wls Junior Member

    Joined:
    Sep 27, 2009
    14
    3
    0
    Location:
    sf bay area
    Vehicle:
    2010 Prius
    Model:
    III
    I tested this on gen 2 pushed my park button while driving in parking lot going about 10mi [speed] found out car will go into neutral and you still have all power steering and power brake control. this would be faster then 3 second power botton. have not try this on my gen 3 assuming this would be same as gen 2.
     
    1 person likes this.
  8. dogfriend

    dogfriend Human - Animal Hybrid

    Joined:
    Feb 26, 2007
    7,512
    1,185
    0
    Location:
    Carmichael, CA
    Vehicle:
    2007 Prius
    No.

    Brakes still function normally, steering effort goes up slightly but still very reasonable.


    Yes.

    I have done it a couple of times, just to see what happens. After 3 seconds, the hybrid system shuts down - the System Relays open and the car goes into a psuedo - ACC mode (the combo meter lights go out except for the shift indicator which shifts to N - it can't shift to P, since you are still moving). Once the car comes to a stop, you can restart by pushing the brake pedal and power button, just like normal.

    Its fun. Try it. :madgrin:
     
    1 person likes this.
  9. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

    Joined:
    Apr 8, 2007
    1,289
    242
    3
    Location:
    Kentucky near Cincinnati, OH
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    I hit P (on my Gen III)by accident while going 30 MPH the other day and it shifted to N. I just shifted back to D and all was well.
     
    1 person likes this.
  10. a64pilot

    a64pilot Active Member

    Joined:
    Aug 3, 2008
    771
    62
    0
    Location:
    Albany Ga.
    Vehicle:
    2010 Prius
    Model:
    III
    I've shut mine down while driving, it acted exactly like a "normal" car does if the engine dies. No big deal.
     
  11. Salsawonder

    Salsawonder New Member

    Joined:
    Nov 28, 2005
    1,897
    47
    0
    Location:
    La Mesa California
    Vehicle:
    2010 Prius
    Model:
    IV
    Thanks to everyone out there who is brave enough to do trial runs on these things!!
     
  12. JasonPro

    JasonPro Junior Member

    Joined:
    Jul 19, 2009
    72
    15
    0
    Location:
    Rockville MD
    Vehicle:
    2010 Prius
    Model:
    IV
    I tested out turning my gen III off while moving at around 10 mph recently. It works as advertised. The MFD stayed on and displayed a big notice that said "Shift to P". Of course I waited until I could stop on the side of the road before I did and then I restarted it.

    I didn't try restarting the car while moving. Anyone try that?
     
  13. dogfriend

    dogfriend Human - Animal Hybrid

    Joined:
    Feb 26, 2007
    7,512
    1,185
    0
    Location:
    Carmichael, CA
    Vehicle:
    2007 Prius

    I think that would be difficult/impossible for 2 reasons:

    1. You need to have your foot on the brake (firmly) while pressing the Power button.

    2. I *think* the car shifts to P once you press the Power button. I'm not willing to test that while the car is still moving. :madgrin: