GM Service Manual Online
For 1990-2009 cars only

The "OnStar®" operation is actually a combination of many different technologies working together to form the OnStar® Service.

    â€¢ Cellular Telephone Equipment with Handsfree Audio Processing.
    â€¢ Cellular Data Modem.
    â€¢ Global Positioning System ( GPS) satellite navigation system.
    â€¢ GM Class 2 Electronic Communications between Vehicle Component Modules.
    â€¢ GM Universal Asynchronous Receiver Transmitter (UART) communications on vehicles with limited Class 2 communications.
    â€¢ Entertainment and Communications buss (E&C) Communication between vehicle entertainment and comfort modules.
    â€¢ Desktop computer software allowing the OnStar® Center advisors to send/receive data to the vehicle over the cellular modem.
    â€¢ Map software that allows the OnStar® Center to view the vehicle's exact location superimposed on a computer generated map.
    â€¢ Extensive database storage and retrieval capabilities to allow OnStar® Advisors the ability to quickly access requested information.