The steering wheel position sensor may fail, resulting in the service stability message being displayed.Google+
Car Problem Reports
Cadillac STS Steering Wheel Position Sensor May Fail
Cadillac STS Problem
Average Mileage: 63,000 mi (31,000 mi - 95,000 mi)
Visitor, 2005 Cadillac STS, 31,000 mi
Squeeking noise when turning wheel. Service stability light comes on.
stability control and brake assist light up. It seems that this is a problem with most cadillac models...