[markwb]

What is the year & trim level of your Bonneville? Sounds like a 2000+ SSEi. Anyway, it could be any number of things. You'll have to pull codes with a scan tool to get more specific detail. There are several components that make up the stability system. To name a few: steering wheel position sensor, yaw & pitch sensors (accelerometers), and the wheel speed sensors. All these sensors provide input to the stability system. Hope this is a little help. Good luck with it, give us some feedback if you resolve the problem.