My Prius seems to overreact when it goes over bumps. I frequently get the slippery road symbol, and even when I don't get it, I sometimes feel the car reacting to the bumps. Is this an idiosyncracy of my car, or it is typical of Priuses (Prii)? If the latter, is it typical of Toyotas in general?
Are you on the brake peddle when you go over the bumps?
I ask because cars with ABS can shudder if the brakes are applied as the wheel spins and locks as a result of the ABS system cutting in. Happens on my BMW with ABS as well, especially over railroad crossings. Dunno, but I wouldn't worry about it if it brakes normally on regular stops at intersections.
B~
The wheel spin indicator has nothing to do with braking or the ABS system. If you've ever driven a Prius up a bumpy hill on a gravel road you'll know that the indicator will constantly go on and off whenever any wheel loses full traction and begins to spin. The car will override driver acceleration pressure until such time as the wheel(s) have reduced rotational speed to maximise forward momentum with no loss of control. The sensitivity of the system has obviously been optimised for asphalt roads - it tends to overreact on gravel roads. The system makes turning out into high speed traffic from a gravel road a frightening experience. It's certainly not a pleasant experience to have just pulled out onto a highway with your foot down with trucks coming at you only to find the car loses almost all acceleration.
OH!!!!! So THAT'S what that is. Yes, and it happens on non gravel roads too, esp. when I [try to] accelerate quickly. That is not good!!!!! I wonder why I never experienced this before I got the Prius. It scares the bejeebers out to of me, esp. if I do have to get out of wherever I am very quickly!
I don't think that what you are experiencing is normal, especially on asphalt roads. In my 2+ years of driving my Prius on various road surfaces I have seen the "slippery road" lamp light up once when I hit some gravel on a curve. I have never lost power when I asked for it although I admit that I don't often drive on snow or ice.
Kari
Mine did just this morning. I was turning out onto pavement from loose gravel. I stepped on the gas, lurched forward, the light flashed, the motor shut down, the wheels grabbed and then I pulled onto the pavement. Lucky I wasn't trying to merge into traffic.
Bill
Isn't it!!!! That is just darned scary. Is this typical of all Toyotas or just the Prius? Boy, it makes it hard to pull out if you take this into consideration!!!!
Interesting. Maybe it's more pronounced in my car for some reason? I would expect this on snow/ice--even possibly on wet roads.
Anything that reduces traction will do it. Gravel can be almost as slippery as ice. Static friction is also greater than moving friction, so once your tires have "broken free" of the surface for any reason, such as bouncing off a bump or accelerating too hard while making a turn, they can start sliding.
Consider that if the system wasn't there you'd just be spinning your wheels; so it's not slowing you down, it's adding life to your tires (and to your paint: less gravel gets flung up).
My 2005 Prius is the first car I've driven with this feature. Testing it, I found it works very well when accelerating through snow-covered curves, usually gets me up my driveway, but poorly in the above-described situation. The problem IMHO is that the recovery from a momentary loss of traction takes too long.
Agreeing with all that you write, I just want to add that in my car it seems to take longer to recover from the loss of traction than is desirable. A wheel slips, the engine shuts down, traction is regained, and it then takes too long to reestablish acceleration, creating a dangerous situation for someone merging into traffic.
It is sure noticeable!!!! Interestingly, I rarely saw the slippery road symbol when I was actually on snow/ice (and the Prius seemed to handle such things as well as my AWD VW did!); I see it more in dry roads, esp. when going over bumps. And sometimes even when I don't see that symbol, it FEELS like the car is compensating in the same way....
Well, it may shorten MY life by hesitating when I need to pull out!!!!
I will say that the first time I noticed this momentary shutdown, I was accelerating and turning. The last time, I was going straight out of a stop. I was not aware of gravel or anything else on the road.
Can the traction control, or whatever it is called, be turned off? My non-Prius has a button on the dash that disengages the traction control, and the owners manual suggests disengagement when, for example, rocking loose in snow.
Oh! I'll have to check that out. I don't think I have noticed any such setting on the dash, but maybe there's an on-screen setting. Thanks for the suggestion! I'll look!
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