Vehicle Interface Unit: Notes
NOTE:
Never exchange OnStar(R) vehicle integration units (VIU), or vehicle communication units (VCU) from other vehicles. Transfer of OnStar(R) components from other vehicles should NOT be done. Each OnStar(R) component has a unique identification number. VIU has a 10-digit Specific Station Identification (STID) and the VCU has a 10-digit specific Electronic Serial Number (ESN). These identification numbers are used by National Cellular Telephone Network and OnStar(R) systems, and are stored in General Motors vehicle history files by VIN.