2010 Toyota Avalon Owners Manual - Page 289

3-3. Using the hands-free system (for cellular phone) Setting voice guidance volume STEP 1 Select "Guidance Vol" by using Change the voice guidance volume. To decrease the volume: Turn . STEP 2 counterclockwise. To increase the volume: Turn Initialization STEP 1 clockwise. Select "Initialize" and then "Confirm" by using . STEP 2 Select "Confirm" by using a voice command or again.