One important thing James isn’t telling you is that if you’re on a discounted corporate account, usually provided by your association with certain agencies, or your employer, you’re out of luck. You’re under an agreement that can’t be modified by you. You have to give up your association, along with any discounts to be able to add your car data. OnStar is better at helping you get answers. However, they too may tell you to contact att. If the latter applies, you’re going to end up buying OnStar unlimited data plan for $20.00/month. It’s provided and billed by att.