2011 Chevrolet Volt Owner's Manual - Page 329

Driving and Operating Sport Mode Mountain Mode 9-27 Mountain Mode will not change normal vehicle braking performance for steep downhill grades. See Hill and Mountain Roads on page 9‑10 and Electric Drive Unit on page 9‑32. Press the DRIVE MODE button to select Mountain Mode. If steep hill driving is expected, it is recommended to select Mountain Mode at least 20 minutes before driving on steep grades. This will allow the vehicle time to build a sufficient battery charge reserve. The engine may run when Mountain Mode is selected. If Mountain Mode is entered before four bars of battery charge, the engine will run at a higher speed to build battery charge reserve. If Mountain Mode is entered above four bars of battery charge reserve, the estimated electric range will adjust accordingly. Sport Mode provides more responsive acceleration than Normal Mode, but can reduce efficiency. Use Normal Mode whenever possible. Press the DRIVE MODE button to select Sport Mode. Press the DRIVE MODE button again to return to Normal Mode and it becomes active after three seconds. The Sport light comes on when Sport Mode is selected. See Sport Mode Light on page 5‑26. Each time the vehicle is started, it will return to Normal Mode. Mountain Mode should be selected at the beginning of a trip before climbing steep, uphill grades and when expecting to drive in very hilly or mountainous terrain. This mode maintains a reserve electrical charge of the high voltage battery to provide better grade climbing performance. While driving in Mountain Mode, the vehicle will have less responsive acceleration.