Brake Sensor problems of the 2005 Toyota Sienna

I've only had the van for 5 months and this problem has occurred over a dozen times, beginning with the day I bought it. And every time this problem has occurred I've been driving on dry roads. It usually happens when driving around a corner, anywhere from 35-65 mph, far. All of a sudden the traction control light starts beeping, the brakes engage on their own, and then engine makes a loud noise (likely downshifting itself). It's as though the vehicle thinks it is slipping, even though it is not, I drive very cautiously so it's not me flying around a corner super fast, it also happens when my partner drives the van as well. I finally took the van to a mechanic and they told me it was the steering angle sensor that was faulty and needed to be replaced, so I spent $900 to have it replaced. I've had the van back for less then 2 weeks and just tried to take it on a road trip, got about an hour from our house and it did it again 3 times in less then 15 minutes, again driving on dry pavement and when driving on a windy highway. It's terrifying when this happens especially because it always happens when we're going around a corner, it's very dangerous and scary. It seems to be happening with a lot of other Sienna�s, even newer ones. This is an expensive problem that desperately needs to be addressed, someone is going to wreck and die from this if they haven't already.

While driving around curves with dry pavement on highways and exit/entrance ramps at highway rates of speed (55-65 miles per hour or less) the anti-lock brake system engage,s causing the van to pulse and slow down unexpectedly. It disengages once the wheel straightens. We first tried to trouble shoot with our local mechanic with no success, prompting us to have our local Toyota service department attempt to diagnosis. Initially they said they were not able to diagnosis the problem or replicate it on a local highway (as it does not occur on every curve encountered) and were ready to send us home without any remedy. This was unacceptable. With our persistence they hooked it up to a computer and determined(without guaranteeing) it was the steering angel sensor and replaced it. Now without returning the van to us, they want us to replace the rack and pinion system for even more cost, again, without guaranteeing this will alleviate the problem. Per our reading up on this problem, we have found that this appears to be problem for other 2005 Toyota Sienna minivans.