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.

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