hi in other cars i've driven with stability control, there is a light or beeper that comes on to indicate that it has kicked in. the prius hasn't indicated this for me, and i haven't been able to feel it work either. is there a way to "test" it?
A good, safe way to test it is to find an icy parking lot and try to do some hard turns. You don't need much speed, either. With stability control, it may not give any visual or audible notification if it is working. You should notice that instead of understeering, and plowing, the car is able to stay pretty close to curve of the turn, as it does on dry road. If the situation goes beyond what VSC can handle, you'll get the warning beeps. VSC is doing the best it can, but it's just not able to fully control the situation (ie understeer on ice at high speed). There's also a slip icon that you may see if you lose traction, like flooring it from a stop, while making a right turn.
Look for a larger parking lot where people's cars have leaked oil and there are no pesky light poles to run into. During the day when it is light, find the oiliest spots. Then, late at night when it is empty and after a light rain, go back and have some fun. Loose gravel should work too, but I wouldn't try that without mud guards. There is a yellow light on the dash that should flicker, and with the stock integrity tires, almost eveyone has seen it. If you haven't, maybe you should have a dealer check it out.
Oh yes, I forgot to mention that. If you have huge tires on the back and a great big shark fin antenna, you can also test the VSC by turning the wheel as you go over railroad tracks. If you ever get near Portland, OR, go out to Multinomah Falls. I notice that my VSC always engages as I cross the foot bridge half way up the trail to the top of the falls, due to the water spay from the falls.
