If you experience very slow fill rates, the CNG fuel filter in the fill valve may require service. If you experience reduced range during CNG operation and none of the conditions described under Filling the CNG Fuel Tanks apply, the CNG fuel tanks may require service. This may be caused by the buildup of water, oil or debris inside the tanks or an inoperative tank valve. In either case, take your vehicle to an authorized GM dealer for service.

Caution: If you smell a persistent natural gas odor or hear a continual hissing sound, you could have a natural gas leak. If the natural gas is accidentally ignited, you or others could be seriously injured. Do not start the engine or drive your vehicle. Have the vehicle towed to an authorized GM dealer for service.