2011 Chevrolet Impala Owner's Manual - Page 233

Driving and Operating 9-25 Running the Vehicle While Parked It is better not to park with the engine running. But if you ever have to, here are some things to know. { WARNING It can be dangerous to get out of the vehicle if the automatic transmission shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll. Do not leave the vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when you are on fairly level ground, always set the parking brake and move the shift lever to P (Park). Follow the proper steps to be sure the vehicle will not move. See Shifting Into Park on page 9‑21. If parking on a hill and pulling a trailer, see Driving Characteristics and Towing Tips on page 9‑42. Automatic Transmission The automatic transmission has a shift lever on the steering column or on the console between the seats. { WARNING Idling a vehicle in an enclosed area with poor ventilation is dangerous. Engine exhaust may enter the vehicle. Engine exhaust contains carbon monoxide (CO) which cannot be seen or smelled. It can cause unconsciousness and even death. Never run the engine in an enclosed area that has no fresh air ventilation. For more information, see Engine Exhaust on page 9‑24. There is a display, located on the instrument panel cluster, that will indicate the gear the vehicle is in. Maximum engine speed is limited on automatic transmission vehicles while in P (Park) or N (Neutral) to protect driveline components from improper operation.