My 2005 Uplander's Stabilitrak system recently went crazy. It started activating without warning and would try and take the steering wheel away from you. Then it showed, "Service Stabilitrak" in the message center. Bad situation. I took it to a local shop to get it diagnosed. It turned out to be a bad yaw rate censor. They wanted $450 to replace it. A new GM part was $250. I found a low mileage used one in a local salvage yard for $85 and replaced it in under 30 minutes. It sits under the center console portion of the dash on the floor board. According to my shop manual, there is no programming involved--just bolt it in. Which I did. That was 3 weeks ago, and it is working fine. I hope this may help someone else.