Pontiac Repair: Bonneville stability control, slippery road conditions, pontiac dealership

Question
My 2000 Bonneville SSEI service stability system warning alarm comes on regularly. I've taken it to our local Pontiac dealership twice and they say the warning indicator hasn't been on during their test drives.They've charged me an hours labor rate each time I've been there. They say they drove the car for approx 20 miles and no alarm. For almost 2 years it comes on for me within a couple of miles. The first time I took it in they did find a leaking rear shock and replaced it and rebuilt the associated rear equipment. When I went back the next day telling them the "service stability system" warning light was still on they said we service what we found was wrong and the warning wasn't on when I brought it in and wasn't on when they test drove it. I decided not to worry about it and am now wondering what the options are to repair when the warning indicator is on.
My question is "when the (service stability system) warning comes on what is needed to be serviced?
I've found in the last few weeks of slippery/icy roads that it feels like the car wants to take off on me at even 55 miles per hour. Pretty bad for new Michelin X Ice radials and a big heavy car and other cars flying by. I'm not an inexperienced driver, I'm 49 and have an RX8 and a Stealth and a bike so I am wondering why I feel like I can't control a big wide track car.
Regard,
Phil

Answer
Hi Phil:

Well the stability control system on these cars is pretty complex and on the older ones pleagued with bugs! The system incorportaed the engine/absand steering system all together to all for better handeling in slippery road conditions. Without knowing what code keeps setting in this I can't even begin to tell you where ro start looking. Some of the "BIG BOX" auto parts stores will scan your car for any codes for free try that first and see what codes are stored in the abs system. That is where the stability control codes are stored. On those cares we had a lot of issues with the steering wheel position sensor going bad That is a VERY likely cause. Also thses cars were noted for abs wheel speed sensors going bad causing the abs/stabilitycontrol lamps to come on together. Good Luck :)