OnStar® Reconfiguration Procedure
Within the VIU and VCU are a set of unique numbers that identify the OnStar® customer and the specific vehicle the modules reside in. These numbers, the Station Identification Number (STID) and the Electronic Serial Number (ESN) are transmitted over the cellular network when an OnStar® key press is made and are essential for proper identification and connection to the OnStar® Call Center. In the event the VIU or VCU requires replacement, the OnStar® Reconfiguration procedure must be performed. This procedure allows for the new STID and ESN within the replacement modules to overwrite the old numbers and update customer and vehicle information at the OnStar® Call Center. The Reconfiguration process is explained within the VIU and VCU module replacement procedures.