Vsa Warning Light On problems of the 2007 Toyota Sienna

As I drive on dry roads at speeds between 35 - 65mph, my car indicator lights and alarm sound off about vsc (vehicle stability control) and slippery road lights on my dashboard. My vehicle's steering and braking are affected by it. It starts to rattle the steering wheel and the braking pumps - causing a reduction in speed and control for the driver. It caused me to fear a possible vehicular accident so much that I pulled off the road. The problem then disappears and doesn't reappear until I encounter a similar driving condition. I fear that if this occurs on a crowded highway, it will cause me to get into a vehicular accident due to the abrupt loss of control. My minivan was purchased to keep my family 'safer' and this experience is causing me to fear using this vehicle. After conducting an internet search it appears to be happening to Toyota Sienna vehicles between model years 2004 - 2008. Mechanics don't seem to understand how to fix other than resetting the sensors; which doesn't fix the problem but just delays its reappearance. In all cases, I experienced this problem only while driving at speeds between 35mph and higher. It's occurred on dry and wet roads, usually while on a curved road.