2001 GMC Sierra 1500 Pickup Owner's Manual - Page 181

Tow/Haul Light (Automatic Transmissions Only) This message is displayed when the tow/haul mode has been activated. When the ignition is on, the fuel gage tells you about how much fuel you have left in your tank. The gage will first indicate E (Empty) before you are out of fuel, and you should get more fuel as soon as possible. Here are some situations you may experience with your fuel gage. None of these indicate a problem with the fuel gage. D At the gas station, the fuel pump shuts off before the gage reads F (Full). D It takes a little more or less fuel to fill up than the For more information see, "Tow/Haul Mode" in the Index. Fuel Gage fuel gage indicated. For example, the gage may have indicated the tank was half full, but it actually took a little more or less than half the tank's capacity to fill the tank. the ignition. D The gage goes back to E (Empty) when you turn off If you have a diesel engine, see "Fuel Gage" in the Diesel Engine Supplement. United States Canada 2-98