Last post on Mar 27, 2013 at 6:44 AM
You are in the Toyota Prius Maintenance & Repair
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
#140 of 366 Re: 2006 Prius Braking problem [broodha]
Feb 05, 2010 (6:49 am)
Now that I think about it, you are right: I don't need to have had pressed on my brakes for the car to lurch forward and to have the VSA light come on. What is interesting is that I know for sure that my model does not have the VSA option. So I have a hard time believing that is the intended function of the VSA when it is not even equiped for my vehicle.
For the other problem, yes it is very frustrating and dangerous in my opinion. I have had several close calls with other cars almost hitting me, when I thought I'd be able to accelerate in time but instead got stuck in traffic. If this issue is pervasive for all hybrid cars, then I am not going to buy a hybrid again.
I do encourage everyone else to go ahead and file a complaint via NHTSA. So far it seems like Toyota is only considering recalling the 2010 model.
#141 of 366 Re: 2006 Prius Braking problem [ericqli]
Feb 05, 2010 (8:35 am)
I concur - call the NHTSA and file your complaint. I have had similar occurances as you. However, my accident happened in a situation that was simply my attempt to stop in a traffic jam on a busy city street. Slow speed, pushed the brake with aggression as the car in front of me did. I would normally have stopped with about 4 feet to spare - however, the brakes did not engage until I was four feet away. Some skidding and smash into the car! In no way was the accident due to a lack of my attentiveness as a driver. Now I pay inflated insurance rates and paid my deductible for repair costs. The sad thing is that my insurance company had to pay a significant chunk of the repair costs because Toyota did not pay enough attention to detail (or ignored it). And everyone knows what happens when insurance companies have increasing claims. Everyone has higher fees - this is especially less desirable in this "buckle down" economy.
#142 of 366 Re: 2010 Prius Owner with Brake issue [wwest]
Feb 05, 2010 (9:10 am)
re: ABS characteristics: Intuitively, it always seemed to me that, if one could just hold brakes close to the loss of tractrion point, then stopping would be faster than ABS pulsing which has a percentage of no-brake force at all. Thanks for the confirmation.
re: Unexpected brake-force. Yes, our 2010 Tacoma does have BA (brake assist). I will explore the conditions you suggest will cause the variability.
Feb 05, 2010 (9:50 am)
The only thing that is good in the Prius is the gas mileage. We are averaging 47 mpg, less than about 20.00 for a fill-up. Other than that the Prius is very small, even the cabin. It is difficult to see through the back window since half of it is small. Good thing for the back up camera. My engine quit after hitting a "chuck hole" and it was difficult to start. Reported it to Toyota Service and they said "should not have happened, but no notice from Toyota for any problems". The Prius is fine for a small person but not comfortable for the Plus size person. I would not own another Prius.
#144 of 366 Re: 2010 Prius Owner with Brake issue [wwest]
Feb 05, 2010 (11:49 am)
You state: " It is not at all unusual for ABS activation to result in elongating your braking distance in a fairly slippery surface by an extraordinary measure."
The whole purpose of ABS is to shorten your stopping distance, not lengthen it. It is a very effective system on most cars. Toyota apparently does not have the interaction of the friction brakes and regen braking worked out yet. So in the meantime, I will be turning on my hazards when I see a Prius behind me since my car has ABS that does what it is supposed to do (shorten stopping distance) and will thereby avoid getting rear ended by the half baked Toyota if there is a need for some hard braking.
I probably should also turn on my hazards when any Toyota is behind me to avoid getting rear ended because of some unexpected acceleration event. The roads just aren't safe anymore.....
#145 of 366 Re: 2010 Prius Owner with Brake issue [buyamerican2]
Feb 05, 2010 (2:45 pm)
"..The whole purpose of ABS.."
Is to optimize braking ability along with directional control simultaneously. Read any current owner manual to verify this. Absent ABS during hard/heavy/panic braking there is a clear and certain danger of loss of directional control due to the front tires locking and skidding. ABS activation results in allowing the brakes to exert the maximum level of braking while still allowing the driver to maintain directional control.
Once someone develops an inexpensive (cost-effective) "linear" brake application servo system to replace the current "bang-bang" system things might improve significantly.
Until then it would clearly be wiser to disable ABS until VSC detects the need.
#146 of 366 Re: 2006 Prius Braking problem [techie2003]
Feb 05, 2010 (2:49 pm)
Go back and read post #132
#147 of 366 Re: 2006 Prius Braking problem [broodha]
Feb 05, 2010 (2:58 pm)
You too...go back and read post #132
"..It seem to exacerbate the problem if I'm turning..."
If the Traction Control system detects front wheelspin/slip and you are turning then it is QUITE CLEAR that you are applying more engine (HSD) torque to the front wheels than is safe for current roadbed circumstances. This is a FWD vehicle so loss of traction, even momentarily so, on the driven and stearing wheels must be quickly addressed, moreso if the VSC system gets into the act. So in a turn wheelspin/slip will probably result in the activation of both functions, TC and VSC.
Your Prius has an unusual amount of low speed acceleration torque for its weight along with tires that are primarily designed for low rolling resistance, not TRACTION.
#148 of 366 BMW brake "pre-charge"
Feb 05, 2010 (3:04 pm)
Toyota might want to look into the methodolgy of BMW's technique wherein the brake calipers are "pre-charged" with pressure if the rain-sensing windshield wiper system senses rain.
BMW apparently applies just enough brake fluid pressure to the calipers to bring the brake pads into slight contact with the rotors. That apparently helps to keep the rotors dry in case the brakes needed.
#149 of 366 Re: 2006 Prius Braking problem [broodha]
Feb 05, 2010 (6:29 pm)
You describe the problem very well. I have a 2006 Prius with VSC and I have the same problem on braking - hit a dip or rough spot in the road and the car stutters, the VSC light flashes, and I feel a lack of control for a second or two. I have not had the acceleration problem. I have not had this issue with any other car.