See also:

Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum capacity, this message may come on. Push to try the call again or try again after driving a few miles into another ce ...

Electronic Range Select (ERS) Mode
ERS or manual mode allows for the selection of the range of gear positions. Use this mode when driving down hill or towing a trailer to limit the top gear and vehicle speed. To use this feature: ...

Reactivation for Subsequent Owners
Push and follow the prompts to speak to an Advisor as soon as possible after acquiring the vehicle. The Advisor will update vehicle records and will explain the OnStar service offers and options ...