OnStar - VCU or VIU Reprogramming

VCU or VIU REPROGRAMMING
After replacement of the VCU or VIU, the OnStar system must be reprogrammed. This is accomplished by putting the ignition in the accessory position, pressing and holding the Call Answer/Call End Button for approximately 10 seconds until the telltail lamp illuminates red. The telltail lamp will remain red during the programming process then change to green when programming is completed.