2009 GMC Yukon Owner's Manual - Page 153

CAUTION: (Continued) 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. • The vehicle's exhaust system has been modified, damaged or improperly repaired. • There are holes or openings in the vehicle body from damage or after-market modifications that are not completely sealed. If unusual fumes are detected or if it is suspected that exhaust is coming into the vehicle: • Drive it only with the windows completely down. • Have the vehicle repaired immediately. Never park the vehicle with the engine running in an enclosed area such as a garage or a building that has no fresh air ventilation. { CAUTION: 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 2-46. 2-47