Highlander Hybrid VSC Alarm

I have a 2006 Toyota Highlander Hybrid, all wheel drive, with 53,000 miles. Two months ago I had the tires rotated (all tires are the same size and age) and the engine battery replaced. Immediately afterward I started experiencing intermittent VSC alarms. When this happens the brakes become mushy and I believe that only the rear brakes are operating. To get rid of the alarm I simply turn the engine off for 15 seconds and restart.

Of course I took it to the dealer and they said the VSC computer had to be replaced ($1940). I didn't have the money, so I kept driving the car. Now I realize that the problem is associated with how I use the brake pedal. If I release the brake pedal with a swift motion (you hear the pedal pop back up), I don't have the problem. If I slowly release the brake pedal or have the car slide forward with my foot on the brake, I get the alarm.

I took it to a second dealer (the mechanic was a friend of a friend) and he also tried to adjust the problem with no success. After driving the car with this problem for two months, I've stopped getting the VSC alarm except possibly once every couple of weeks.

This seems to be more of a sensor problem to me than a computer problem. Any suggestions?

Thanks, Bill