2003 GMC Sierra 1500 Pickup Owner's Manual - Page 291

The traction off light will come on under the following conditions: The Traction Assist System is turned off, either by pressing the TAS on/off button or turning off the automatic engagement feature of the TAS. The transmission is in FIRST (1); TAS will not operate in this gear. This is normal. The vehicle is driven on an extremely rough road. When the vehicle leaves the rough surface, slows down or stops, the light will go off and TAS will be on again. This is normal. A Traction Assist System, Anti-Lock Brake System or engine-related problem has been detected and the vehicle needs service. If the vehicle has been driven with the TAS system on for long periods of time, or if the vehicle has gone through many several high speed braking maneuvers the system may be automatically disabled. The system will automatically re-enable after approximately two minutes of not using the brakes. See Traction Off Light on page 3-4 1. The Traction Assist System, as delivered from the factory, will automatically come on whenever you start your vehicle. To limit wheel spin, especially in slippery road conditions, you should always leave the system on. But you can turn the TAS off if you ever need to. You should turn the TAS off if your vehicle ever gets stuck in sand, mud or snow and rocking the vehicle is required. See Rocking Your Vehicle under If You Are Stuck: In Sand, Mud, Ice or Snow on page 4-50. To turn the system on or off press the TAS on/off button located on the instrument panel. If you used the button to turn the system off, the traction off light will come on and stay on. You can turn the system back on at any time by pressing the button again. The traction off light should go off. 4-10