2006 GMC Envoy Owner's Manual - Page 299

Traction Control Off In this mode, stability control and brake-traction control are functional. Engine speed management will be modified and the driven wheels can spin more freely. This can cause the brake-traction control to activate more frequently. If the controller detects excessive wheel spin in this mode, the StabiliTrak® indicator light may blink and the STABILITRAK ACTIVE message may be displayed to warn the driver that damage may occur to the transfer case. 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 may want to "rock" your vehicle in an 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 Your Vehicle is Stuck in Sand, Mud, Ice, or Snow on page 4-44 for more information. When the transfer case is in 4LO, the stability system is automatically disabled. The StabiliTrak® light will come on and the STABILITRAK OFF message will appear on the DIC. The StabiliTrak® system cannot be turned on until the vehicle is switched to 2HI, 4HI, or 4AWD. StabiliTrak Off In this mode, both stability control and part of the traction control system are disabled. Your vehicle will still have brake-traction control, but will not be able to use the engine speed management system. You may still hear system noises as a result of the brake-traction control coming on. If the controller detects excessive wheel spin in this mode, the StabiliTrak® indicator light may blink and the STABILITRAK ACTIVE message may be displayed to warn the driver that damage may occur to the transfer case. ® 4-11