2002 GMC Envoy Owner's Manual - Page 207

Compact Disc Messages (Err): If you're driving on a very rough road or if it's very hot, the disc may not play and Err (error) may appear on the display. When the road becomes smooth or the temperature returns to normal, the disc should play. If the disc comes out, it could be one of the following: AM-FM Stereo with 6-Disc Compact Disc Player with Programmable Equalization and Radio Data System (RDS) (If Equipped) D The disc is upside down. D It is dirty, scratched or wet. D It is very humid. (If so, wait about an hour and try again.) If any error occurs repeatedly or if an error can't be corrected, please contact your dealer. (CAL ERR): This message is displayed when the radio has not been calibrated properly for the vehicle. You must return to the dealership for service. (LOCKED): This message is displayed when the THEFTLOCKR system has locked up. You must return to the dealership for service. Standard radio--BoseR not shown Playing the Radio VOLUME PWR: Press this control to turn the system on and off. To increase volume, turn the control clockwise. Turn it counterclockwise to decrease volume. 3-33