today I found when approach a stop sign, VSC always engaged except when I extremely careful. It appears nothing is wrong. Temp at 50, very little water on ground. When I just about to completely stop, VSC engages 3 times, and I feel like car suddenly accelerated, then stops. Anyone has similar experience? Thx
Buy new tires with better traction ratings. The 2004-2005 models have a very aggressive traction control system. The only way to reduce the VSC or traction control system engagement is to use better tires. I don't have any issues at all unless I hit ice. I used to experience the traction control power cut frequently when I had to original OEM Integrity tires on the car.
It's not VSC. VSC works to keep your Prius going straight and under control, as in losing control around a corner. Generally it's hard to notice VSC, unless you exceed its ability to correct the problem. Perhaps you are thinking of ABS? Tom
Can't say for the Prius, but we took my friends Subaru outback offroad and drove it like a rally car(Very BAD idea). Short of the story, having defective or bent backwards ABS sensors on the subaru would trigger the ABS engaging every time the brake pedal was pressed. Check your ABS sensors.
The last time someone posted symptoms like this it was due to mismatched tires. Are all of your tires the same size? Are some of the worn and the others relatively new? Any difference in tire circumference can cause the ABS to have a hair trigger. JeffD
Thank everyone! You guys hit the nails on all accounts. But what still puzzles me is that it never happened before! Yes I have mismatched tires on front, a Goodyear viva 2 with 4/32 and a Cooper with 8/32 roughly. The rear tires are viva with 5/32 left. I will replace 3 viva and put the Cooper to rear. Just bought 3 almost new tires at price of one (10-11/32), two of them are also viva 2, and the other is Goodyear Integrity. The seller is a Toyota technician. He said those tires come from trade in cars. In order to certify those trade ins, the dealer replaced those mismatched almost new tires before put the car on sale. He said that I will not feel any difference if I mismatch the Cooper and Integrity in rear.
Since the front wheels do almost all of the stopping work, having a matched pair up front will definitely confirm or rule out tires as the cause. You have mentioned treadwear, but what about the size of the Cooper vs. the Goodyear?
If mismatched tires are the cause, then I would expect the included donut spare tire to cause the same problem. Somehow though, I don't think Toyota would let that one slip by..
That's a good argument I think. Maybe Toyota engineers are smart enough to build their VSC software to handle the spare tire case, since it is a known significantly smaller size.
I read long time ago, that the first 10 minutes of raining period is the most slippery period, because the oil on the road is not washed away. In my case, it rained a very little but stopped a while ago. There is no visible water reflection on road, but I can definitely tell it is still wet.
