2004 GMC Yukon Owner's Manual - Page 310

The Stabilitrak® mode button is located on the instrument panel. It is recommended to leave the system on for normal driving conditions, but it may be necessary to turn the system off if your vehicle is stuck in sand, mud, ice or snow, and you want to "rock" your vehicle to attempt to free it. It may also be necessary to turn off the system when driving in extreme off-road conditions where high wheel spin is required. See If You Are Stuck: In Sand, Mud, Ice or Snow on page 4-50. When the transfer case is in 4 low, the stability system is automatically disabled, and the STABILITY SYS DISABLED message will appear on the DIC. In 4LO, the Stabilitrak® button only turns the traction control system on and off. Stabilitrak® and part of the traction control system can be turned off or back on by pressing the Stabilitrak® button. All-wheel drive vehicles must be in all-wheel drive mode to turn the system on or off. When the system is turned off, the traction off light will illuminate, and the STABILITY SYS DISABLED message will appear on the DIC to warn the driver that both the stability system and part of the traction control system are disabled. Your vehicle will still have brake-traction control when Stabilitrak® is off, but will not be able to use the engine speed management system. See "Traction Control Operation" next for more information. When the Stabilitrak® system has been turned off you may still hear system noises as a result of the brake-traction control coming on. 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 (engine speed management) and by applying brakes to each individual wheel (brake-traction control) as necessary. The traction control system is enabled automatically when you start your vehicle, and it will activate and display the TRACTION ACTIVE message in the Driver Information Center (DIC) if it senses that any of the wheels are spinning or beginning to lose traction while driving. If you turn off Stabilitrak®, only the brake-traction control portion of traction control will work. 4-12