Just bought a car with OnStar. Activated the free trial, and the attendant was trying to talk me into their phone service minutes. Interestingly, tried to sell that based on the scenario where my phone battery is dead (I have a car charger). It did e-mail me to tell me the car is due for the 100,000 mile service (oh, joy), but all diagnostics report OK. I'm thinking I'll just turn it off after the trial period. I don't see me using it it for phone service or directions when my smart phone already does those things. If OnStar reported a problem, then wouldn't these same problems also trigger check engine lights, air bag warning lights, or other lights?