Automatic Volume Control
WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
With automatic volume, the audio system adjusts automatically to make up for road and wind noise by increasing the volume as vehicle speed increases. The Bose amplifiers and base radios use a vehicle speed signal, received via serial data circuits to adjust volume. To adjust volume based on speed, press the AUTO VOL button to select LOW, MEDIUM, or HIGH. To turn AUTO VOL off, press until AVOL OFF is displayed.