2009 GMC Savana Van Owner's Manual - Page 209

To turn on the StabiliTrak system, press the StabiliTrak button again. StabiliTrak will automatically turn back on when the vehicle speed exceeds 20 mph (32 km/h). One chime is heard and the StabiliTrak light will turn off. When the StabiliTrak system has been turned off, system noises may still be heard as a result of the brake-traction control coming on. It is recommended to leave the system on for normal driving conditions, but it may be necessary to turn the system off if the vehicle is stuck in sand, mud, ice or snow, and you want to "rock" the vehicle to attempt to free it. See If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow on page 4-17. The StabiliTrak system may also turn off automatically if it determines that a problem exists with the system. If the problem does not clear itself after restarting the vehicle, see your dealer/retailer for service. Traction Control Operation The traction control system is part of the StabiliTrak system. Traction control limits wheel spin by reducing engine power to the wheels and by applying brakes to each individual wheel as necessary. If the brake-traction control system activates constantly or if the brakes have heated up due to high speed braking, the brake-traction control will be automatically disabled. The system will come back on after the brakes have cooled. This can take up to two minutes or longer depending on brake usage. The traction control system may activate on dry or rough roads or under conditions such as heavy acceleration while turning or abrupt upshifts/downshifts of the transmission. When this a reduction in acceleration may be noticed, or a noise or vibration may be heard. This is normal. Adding non-dealer/non-retailer accessories can affect the vehicle's performance. See Accessories and Modifications on page 5-3 for more information. StabiliTrak System Operation The StabiliTrak system is normally on, except when the system is initializing or has been disabled with the StabiliTrak button. The StabiliTrak system will automatically activate to assist the driver in maintaining vehicle directional control in most driving conditions. When activated, the StabiliTrak system may reduce engine power to the wheels and apply braking to individual wheels as necessary to assist the driver with vehicle directional control. If cruise control is being used when StabiliTrak activates, the cruise control automatically disengages. The cruise control can be re-engaged when road conditions allow. See Cruise Control on page 3-9. 4-7