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

Car lurches forward while brakes are applied

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by brakeshoe87, Oct 10, 2013.

  1. brakeshoe87

    brakeshoe87 Junior Member

    Joined:
    Jun 4, 2013
    8
    0
    0
    Vehicle:
    2012 Prius
    Model:
    Two
    I have a 2012 Prius with 15000 miles on it. In the year I have had it, I have had this problem a few times. On rare occasions while I am braking the car seems to lurch forward. In particular I have noticed it while braking and hitting a bump. The problem is that when this happens the car seems to jump forward while the brakes are being applied. My foot is on the brake when it happens, but I am not braking suddenly. That rules out any anti-lock braking. I have had the dealer look at it but since it didn't happen on their test drive they couldn't figure anything out. They did open a case on it in case anything comes up. Has anyone else had a similar problem?

    Dave
     
  2. Simonak

    Simonak Member

    Joined:
    Oct 5, 2013
    51
    32
    0
    Vehicle:
    2010 Prius
    Model:
    III
    Toyota say this is normal.
    I have 2010 and have the same thing happening too but I'm not sure if it is just as Toyota say normal regenerative breaking when hitting a hole or bump.
     
  3. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,113
    10,043
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    I don't see how this rules out ABS. If the bump causes momentary loss of traction, ABS seems likely to get involved.

    So far, this sounds like the common braking surge / lunge / lurch / dropout / pause experienced by many Prius drivers at low to moderate speeds during low to moderate braking, and hitting a bump or pothole or railroad track or metal cover.

    It is the subject of many many threads and a significant amount of controversy here.

    The version I frequently experienced in my 2010 seemed to happen during regenerative braking when some sort of braking upset triggered the ABS. But others have attributed it to ABS only, and some have pointed to similar examples in certain non-hybrids. The 2010s had a recall that significantly reduced the effect. Others have noted it in post-recall cars, but I haven't yet noticed it in my 2012. Some drivers were terrified of it over fear of losing braking in emergency situations, while others felt is was just a touch-and-feel issue, not a safety issue. I believed it occurred only during regenerative braking, not in hard braking situations that bypassed regen, so it didn't particularly bother me.

    If you have more details that separate your particular experience from the events described in the many other threads, please post them here.
     
  4. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,751
    48,964
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i have not noticed this in any of my 3 pri.
     
  5. michinnom

    michinnom Member

    Joined:
    Apr 28, 2013
    162
    29
    0
    Vehicle:
    2010 Prius
    Model:
    N/A
    Yes, because toyota has no idea how to fix it, they call it normal...lol
     
  6. Sabby

    Sabby Active Member

    Joined:
    Sep 17, 2011
    295
    127
    0
    Location:
    SoCal
    Vehicle:
    2015 Prius
    Model:
    Two
    The sequence is likely that you are in regenerative braking mode. The bump causes a loss of traction and the abs is activated. Since the regenerative braking can't be pulsed there is a switch over to friction braking that can be pulsed. The moment of the transition feels like no brakes.

    If it happens push a bit harder on the brake to get the friction brake activated
     
  7. Les_PL

    Les_PL Active Member

    Joined:
    Nov 11, 2012
    317
    248
    0
    Location:
    Gdynia, PL
    Vehicle:
    2009 Prius
    Model:
    III
  8. car compulsive

    car compulsive Active Member

    Joined:
    Aug 6, 2011
    741
    274
    0
    Location:
    Michigan
    Vehicle:
    2011 Prius
    Model:
    Two
    I consider it to be one of the quirks of this car and leave myself a bit longer braking distance. When it happens, it's no longer a surprise and I just keep applying braking pressure.
     
  9. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    5,597
    3,771
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    I could repeat it at will in my 2010 by braking over bumpy railroad tracks situated just before an intersection with a traffic light. This was and still is a daily scenario on my normal commute. My hybrids from other makes don't do it at all.
     
  10. finman

    finman Senior Member

    Joined:
    Apr 9, 2004
    1,287
    111
    0
    Location:
    Albany, OR
    Vehicle:
    2014 Nissan LEAF
    no issues here either.