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.
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#129 of 370 2006 Prius Braking problem
Feb 04, 2010 (1:09 pm)
I have a 2006 Prius. I noticed the issue of the car surging forward momentarily when a pothole or a bump is hit (and the VSA light comes on). Like many others, I thought this was normal and just ignored it. But apparently now Toyota has recognized this as a problem, but only for the 2010 model. I went ahead and filed a complaint on NHTSA's website. I urge others to do the same, so we can get our non-2010 models fixed as well.
Another problem I noticed is that when the road is wet, and if I was at a complete stop and tried to accelerate too fast, the car will actually kind of "slip"--it doesn't accelerate as intended but actually stalls momentarily. The way to overcome this problem is to step on the gas pedal very lightly. So with slow acceleration, everything is fine, but if you tried to rush it, it won't work. This is a severe disadvantage if you are sitting at a busy intersection trying to make a turn, because you want to go fast to avoid be hit, but like I said, trying to go faster will actually backfire.
Has anyone else noticed this?
#130 of 370 Scary stuff.
Feb 04, 2010 (1:35 pm)
The main Toyota brake pedal problem is mechanical and that I can understand.
However it is a whole new ballgame when computers start playing up.
I just think of this thing in front of me and the problems I have, with a need to power cycle the thing every month or so. You cannot do that travelling at 70mph.
Better the old days when brakes were a mechanical function you always seemed to have warning when things were not right.
#131 of 370 Re: 2006 Prius Braking problem [ericqli]
Feb 04, 2010 (1:51 pm)
I have had the same problem in my 2008 Prius. I just figured it was how the Prius worked, I didn't realize it was a problem. But I will definitely be filing a complaint now.
#132 of 370 Re: 2006 Prius Braking problem [ericqli]
Feb 04, 2010 (2:59 pm)
"..Has anyone noticed this?.."
That's called TC, Traction Control. If you try to use too much engine torque for roadbed conditions the drive, driven, wheels will tend to slip. When that happens TC will activate and instantly reduce the drive power from the HSD system. Most of the time it will also apply braking to the slipping wheels.
With a FWD or F/awd vehicle wheelslip/spin of the drive/driven wheels is of such seriously hazardous nature, HIGH potential for subsequent loss of directional control, that the TC reaction to the must be INSTANT, full and complete.
If you happen to also be turning as you accelerate the TC (more likely VSC)functionality will likely be even more firm and sudden.
Keep in mind that for its weight the Prius has an unusual level of get up and go from a full stop. Low speed torque derived from those synchronous AC motors.
#133 of 370 Re: 2010 Prius Owner with Brake issue [buyamerican2]
Feb 04, 2010 (3:04 pm)
"..you better drive something other than a Prius.."
No, not saying that at all.
What I am saying is that if you drive any of the current crop of hybrids that use regen braking you should be prepared for that seat of the pants "feel" of a momentary, millisecond, forward surge. In most cases that momentary "lurch" in brake application will have no detrimental effect.
#134 of 370 Re: 2010 Prius [doobs1]
Feb 04, 2010 (3:16 pm)
I'm in exactly the same boat....supposed to pick up mine Friday....if you get any tips, please let me know....I'm in Canada....how about you?
#136 of 370 Re: 2010 Prius Owner with Brake issue [wwest]
Feb 04, 2010 (5:49 pm)
Nice explanation to the Prius braking characteristics.
We have a 2010 Tacoma 2.7L Auto and after 16,000km (10,000miles) I am bothered by its braking performance and wonder if there are some common software/hardware related deficiencies in Toyota's products, I have two questions.
1. This is our first ABS vehicle and it does seem to be harder to stop with ABS than our old Civic with non-ABS brakes on snowy or icey surfaces. Are there any quantitative results for ABS vs non-ABS performance?
2. The Tacoma also exhibits unexpected brake-force requirements. Usually requiring more force than I think is warranted but occasionally responding to my idea of normal braking pressure. Is this appearing on the Prius as well as other models in Toyota's line-up?
#137 of 370 Re: 2010 Prius Owner with Brake issue [tryingedmunds2]
Feb 04, 2010 (6:22 pm)
1.) There are most definitely times, situations, wherein ABS is a detriment. ABS will ALWAYS extend your stopping distance in panic, severe, braking situation, in favor of allowing the driver to maintain directional. Sometimes that simply is not the optimal thing to do. I have contended for quite some time now that unless the stability control, VSC for Toyota, indicates directional control or directional correction is needed then ABS should be held inactive.
On a highly slippery surface it will sometimes help to apply the e-brake slightly/judiciously along with normal braking. I have had times when it seemed my Jeep would never come to a final, full, stop due to continuous ABS activity. The e-brake would always help.
2.) "..unexpected brake-force.."
That may be due to BA, Brake Assist, if you happen to have that feature. With BA the braking system "watches" the rate at which you depress the brake pedal in order to determine if "this" is a panic or severe braking event. If it determines so then it will actually use the ABS pumpmotor brake fluid pressure to assist your braking effort. In that case it might even extend the HARD braking period should you relax brake pedal pressure somewhat.
As a result "normal" braking will often require more brake pedal force vs if the system detects panic braking and provides the extra assist.
#138 of 370 Re: 2006 Prius Braking problem [ericqli]
Feb 04, 2010 (6:43 pm)
I mentioned earlier about my 2008 brakes not working properly when you hit a rough surface but I did not mention the other problem that you have. I have also had a problem with acceleration if you are on just a small amount of cinders (spread in the winter) or if it is a little slick. You step on the gas to pull out and the car stumbles and hesitates until it takes off again. It is very unsettling if you are pulling out into traffic and the nose enters the intersection and the car stumbles and seems to stall.