2013 Toyota Tundra Regular Cab Owners Manual - Page 327
2013 Toyota Tundra Regular Cab Manual
Page 327 highlights
3-2. Using the audio system Type B and C Press Press Press Press . that corresponds to "MORE". that corresponds to "ASL". that corresponds to the desired mode. Type B: "ON" or "OFF" Type C: "LOW", "MID", "HIGH", or "OFF" ASL automatically adjusts the volume and tone quality according to vehicle speed.