Last post on Sep 03, 2013 at 5:22 PM
You are in the Toyota Prius
What is this discussion about?
Toyota Prius, Brakes, Hatchback, Sedan
Go to NHTSA to file a safety complaint.
Or call Monday-Friday (8 am to 8 pm ET) (888) 327-4236 TTY: (800)424-9153
#359 of 370 Re: Prius Brake issue [bigteej]
Oct 15, 2012 (9:41 am)
What you are experiencing is the "delay" in the transition from regenerative, FRONT wheel ONLY, braking, to frictional braking ONLY, braking on all 4 wheels. Not that the addition of rear braking makes much difference in most cases.
Obviously the car "wants" to use regen braking, especially so if the HV battery charge is close to being marginal. regen braking only occurs on the front wheels...you know, the one's you constantly rely on for directional control.
So any, even the smallest, indication of front wheel slip during braking will be, MUST BE, reacted to instantly. So, would you like to have, with definity, a sudded increase in braking rate, or a "slow" transition into a less pronounced braking mode...?
There is a serious level of MG mass inertia to be ovecome inside the PSD/CVT in switching from "brake" to "neutral". The multiphase rotating electric field(s) inside the MGs cannot "lead" the rotor by too great a margin without the possibly of becoming unlocked.
And you DO NOT want the frictional braking to come online until most of the regen braking has been abated.
Drive the new RWD Infinity to get an idea of the overall driving dynamics of a RWD hybrid vs a FWD.
Hard call for the design engineers.
An ideal solution overall would be ofr the Prius to become a RWD hybrid.
#360 of 370 Re: Sudden acceleration, Prius 2011 [glenda7]
Oct 15, 2012 (9:54 am)
More like "lurch forward" as the regen braking is released, "wound down", during the transition to frictional braking, with all wheel "distributed" FRICTIONAL braking and ABS capability.
Regen braking can be PERFECTLY "metered", fine resolution modulation, moderation, while frictional braking simply cannot be. So Toyota dare not bring on frictional braking until regen braking is mostly "wound down", the PSD has gone from regen mode (reverse[?]) to "neutral"
The only solution I can think of is to ALWAYS brake EARLY and HARD, only lighten the braking once you have slowed to your comfort level with DEFINITY. Always "coast" up to a final stop.
#361 of 370 Re: Prius Brake issue [bigteej]
Oct 16, 2012 (7:11 am)
I'm having the same problems with my 2011 Prius, purchased in July 2011. After only a month or so of driving it, I started to become scared daily by the unsafe driving conditions due to the car's tendency to lurch forward while braking over bumpy ground coming to a stop. It does not help to always "brake early and hard" as another poster suggested because the car simply fails to brake when it hits potholes - it doesn't matter how hard you're pressing the brakes. I also brought this to the dealer's attention last fall and they said they checked the brake system and there was "nothing wrong, that's just how the braking system works." I know that this exact issue is a problem on 2010's but have not found a recall for 2011's and the dealer claims there is no issue on my car.
Well, now this "non-issue" has caused an accident as my husband was driving my car last weekend and the car lurched forward while he was braking over potholes (there are a lot of them around San Diego) coming up to a stoplight and it didn't stop and it resulted in him rear-ending someone. There was no damage to the Prius, just some dings in the bumper of the other car, but $2000 later I feel pretty upset that my Prius clearly is not reliably safe to drive. I'm going back to Toyota soon with my documentation in hand that I brought this issue to their attention months ago and I'd like to see what they have to say now it's led to an accident because they ignored the problem.
I also have other electronic issues with it - smart key system not working well either. It completely failed about 2 months after I got it, then Toyota reset it and it hasn't worked as well as new since. Oh and the radio system sounds terrible, with lots of electronic interference that makes the sound very muted. It will sound clear for a split second when I turn the car on or switch from CD to radio, and then it gets muffled. Dealer also found "nothing wrong" on the radio. I do like the car but am seriously frustrated to have spent so much money on a car that does not perform as a new car should or provide the level of safety a consumer would expect.
#362 of 370 Re: Prius Brake issue [lyanesse]
Oct 16, 2012 (8:04 am)
Keep up the pressure on these problems. I have tried a ton to really fight these issues we are all having. However, on this forum every response seems to be from someone that has been employed by Toyota to pacify the complaints.
#363 of 370 Re: Prius Brake issue [jacquesc]
Oct 17, 2012 (6:11 am)
Most defintely not, NEVER, employed by Toyota...
"Pioneer 10" Osprey
#364 of 370 When/how do the brakes engage when coming to a stop?
Dec 22, 2012 (5:21 am)
I have a 2011 Prius III and would like to know when and how it switches from regenerative braking to normal braking when stopping or slowing down? I am also interested in what happens as I apply the brakes when the cruse control is functioning. This knowledge will help us maximize the regeneration and extend our Prius's brake life.
#365 of 370 Toyota Prius Brake Failures Jeopardize Public Safety
Feb 03, 2013 (10:05 am)
I purchased a new 2012 Toyota Prius and absolutely loved the car....except....
Within one month, I had 3 'incidents,' the first was when it transitioned from battery to motor with such severe force, I initially believed I had been struck in the rear.
The second 2 incidents were BRAKE FAILURE - the pedal traveled to the floor and a dashboard warning light came on - there were NO BRAKES!
I demonstrated the BRAKE FAILURE to the Route 44 Toyota technician repeatedly as he sat in the passenger seat, yet the dealer's response? "No Computer Error Message" !
How often has Toyota employed that phony response??
I refused to drive the vehicle to prevent injury or death to an innocent person, maybe a child in a crosswalk in front of my LEMON Prius.
The comments and complaints posted here seem consistent with the quirky or failed brakes I experienced.
Might I recommend that you post your complaints on the NHTSA web site - that's the only way Toyota will correct this problem.
Consumers also have a right to file a Petition for Defect Investigation with NHTSA in which you itemize other complaints that are publicly available.
You might also consider posting your complaint on the web site of the Center for Auto Safety.
How many innocent people must die or be injured before Toyota corrects this problem?
Whining in this forum doesn't solve the problem.
#366 of 370 Is there a fix?
Mar 27, 2013 (5:44 am)
I have the same issue as everyone else with our 2010 Toyota Prius...hit a bump and the brakes don't work for a short time AND the care 'accelerates.' I've taken the car to one dealer who says the issue 'can't be duplicated' and the other says that Toyota (corporate) does not see this as an issue so it is not covered under my extended warranty. Has anyone had any luck getting their brakes actually fixed? Any advice? I don't want my wife driving around in a car that is going to randomly accelerate when in fact, she wants to brake.
#367 of 370 Any answers? Issues with '06 Prius braking
Jun 18, 2013 (12:45 pm)
I've had the same issues with my 2006 Prius. Feels like you have no control for a second when braking over bumps/potholes. One back road I take often has a 90* corner. I never go fast, it is thickly settled with a park and lots of kids. Maybe 10-15 mph over the bumpy patch just before the corner and the problem happens without fail. I usually am able to go around it but not if someone is coming the other way. Some people are saying to apply the brakes harder, that won't work for me as I am not actually stopping, just slowing. It has happened numerous times in other places but this is one place it always happens and as I said, NOT going fast at all. I've read other blogs where many people have had issues with their 2006 as well so how come there was a recall issued only the 2010?
#368 of 370 Re: Any answers? Issues with '06 Prius braking [rikki22]
Jun 19, 2013 (9:46 am)
I have had that happen with regular cars with anti-lock brakes when braking on bumpy roads. Cars without anti-lock brakes won't do that.