Brake Issues When Starting v (lowercase v for the Prius v wagon. Only 2010 Prius used uppercase Roma

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by PriusPH, Dec 1, 2016.

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  1. PriusPH

    PriusPH Junior Member

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    Location:
    Victoria, BC
    Vehicle:
    2012 Prius v wagon
    Hi Everyone,

    I have a 2012 Prius v (lowercase v for the Prius v wagon. Only 2010 Prius used uppercase Roman numerals for model designation...) Waggon, with an intermittent brake issue. The problem almost always occurs when we start the car. The sequence of events is as follows:

    - press the "power" button with the brake engaged;
    - the car turns on but the engine does not start (not an issue);
    - release the parking brake and put the car in drive;

    At this point the hydraulic pump/brake system is sometimes not engaged. As you begin to release the bake (brake not fully released) the car lurches forward and without the hydraulic bake system engaged you have to apply a great deal of force to get the car to stop again. This is made worse by the fact that we have to park facing down a steep hill therefore you have to try to stop the car going down a hill in drive without the hydraulic brakes. This can be a freighting/jerky experience.

    Normal braking can be restored by stopping the car and putting in back into park. At this point the pump for the hydraulic brakes starts up and the bakes work just fine.

    This has happened both forward and reverse and on our steep driveway and on flat ground. On flat ground, it's not nearly as concerning as the car is easier to stop. In general if we remember to wait a minute and allow the gas engine/brake system to start up it's not an issue.

    We have taken the car to our local dealer (Metro Toyota in Victoria BC), they have looked at the brakes on a couple occasions but have not been able to diagnose or find an issue.

    Any help would be greatly appreciated.

    Thanks
     
    #1 PriusPH, Dec 1, 2016
    Last edited: Dec 1, 2016
  2. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Every time I see a post like yours, it strikes me how wonderfully reliable these cars are compared to another brand I follow and thus how few people have any in depth mechanical knowledge of in depth repair items because the darn things fail so seldom. On my other brand forum, you'd have had several mechanics answering by now with detailed knowledge of the systems. Seldom see that on the Prius forums. Though maybe it occurs on the older models sub-forums since, as the purchase price drops, so do the driver's inclination to self repair.

    Has the system failed from day one or only recently?
    Miles/klicks on the car?
    Any work done on the car through its entire history?
    Parked inside or outside?
    Any sign of rodents (they chew the wiring in the oddest places)?
     
    #2 mikefocke, Dec 1, 2016
  3. PriusPH

    PriusPH Junior Member

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    Victoria, BC
    Vehicle:
    2012 Prius v wagon
    Thanks for the response,

    The issue has been intermittent for at least the last 3 years, after having the dealer look at the car we just lived with it for a while (just made sure we waited a minute before putting the car in drive). My wife scared herself toady when it happened which prompted this post.

    To answer your questions:

    -The car has about 58,000 km.
    -There have been no other mechanical issues with the car (only routine maintenance)
    -The car is parked outside (on our steep driveway)
    -I haven't noticed any rodents but I'll take a look.
     
    #3 PriusPH, Dec 1, 2016
  4. jzchen

    jzchen Newbie!

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    Location:
    Arcadia, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    The reservoir is weird. There is a complicated procedure to check/correct the fluid level because there is an accumulator. I had a difficult time keeping it between the low and high levels because I did not have access to the service manual. As soon as you open the driver's door you should hear the "pump" working and the fluid level in the reservoir will go down first use after a long time sitting. Can you verify whether this is happening first thing in the morning?

    MT2L03 ?
     
    #4 jzchen, Dec 6, 2016
  5. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    Does it happen nose down on the driveway? Nose up?
     
    #5 mikefocke, Dec 6, 2016
  6. EZW1

    EZW1 Active Member

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    Location:
    Phoenix, AZ
    Vehicle:
    2016 Prius v wagon
    Model:
    Four Touring
    I cannot speak for the 2012 model year but my 2016 activates the brake pump when the driver's door is opened, so it's ready to go when the car is turned on (regardless of driving mode). I would be a bit surprised if yours doesn't do this.
     
    #6 EZW1, Dec 7, 2016
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