2008 GMC Envoy Owner's Manual - Page 200

Your vehicle may have a feature called Retained Accessory Power (RAP). With RAP, the audio system can be played even after the ignition is turned off. See Retained Accessory Power (RAP) on page 2-22 for more information. Radio(s) Setting the Clock The radio may have a button marked with an H or HR to represent hours and an M or MN to represent minutes. Press and hold the hour button until the correct hour displays. AM or PM displays for morning or evening hours. Press and hold the minute button until the correct minute displays. The time can be set with the ignition on or off. To synchronize the time with an FM station broadcasting Radio Data System (RDS) information, press and hold the hour and minute buttons at the same time until UPDATED and the clock symbol appear on the display. If the time is not available from the station, NO UPDATE or NO UPDAT will appear on the display. RDS time is broadcast once a minute. After tuning to an RDS broadcast station, it could take a few minutes for the time to update. Base Radio Shown, Bose® Similar 3-66