Your GM Account is where you can view, manage and change your OnStar* plan and find plans and pricing information tailored to your vehicle. Specifically, you can add to or select a different plan, get your vehicle mobile app information, review diagnostic information,* receive vehicle support, manage maintenance and service, access an online Owner's Manual, and review helpful how-to content. Log in using your GM Account, OnStar account, vehicle mobile app or GM Rewards* login.