2005 Toyota Sienna stability control problems

I was driving my 2005 toyota sienna on a dry, straight road at about 30 MPH and for no reason the vehicle stability control (vsc) engaged and brought the car to a violent stop. The nose of the car came down and I could feel the rear of the van begin to lift off of the ground. If I was traveling on a highway at a higher rate of speed, I have no doubt this van would have flipped over. I had to drive to the dealer when this occurred at least ten times while not driving over 10 MPH.

On my 2005 toyota XLE limited, the traction control system engaged on its own while driving about 50 MPH on a flat road in dry conditions, as a result the brakes engaged on its own and the car shook profusely for a couple of seconds. I had to hold onto the steering wheel to maintain control and avoid going into the neighboring lane. My 2005 toyota sienna has 84,000 miles on it. There have been two other incidences when the traction control engaged but the brakes did not.