2008 GMC Yukon Owner's Manual - Page 221

Engine Coolant Temperature Gage Tire Pressure Light This light comes on briefly when the engine is started. United States Canada This light will also come on when one or more of your tires are significantly underinflated. A tire pressure message in the Driver Information Center (DIC), may accompany the light. See DIC Warnings and Messages on page 3-64 for more information. Stop and check your tires as soon as it is safe to do so. If underinflated, inflate to the proper pressure. See Tires on page 5-64 for more information. If a problem is detected with the Tire Pressure Monitor System, this light will flash for approximately 60 seconds and then stay on solid for the remainder of the ignition cycle. See Tire Pressure Monitor System on page 5-73 for more information. 3-47 This gage shows the engine coolant temperature. It also provides an indicator of how hard your vehicle is working. During a majority of the operation, the gage will read 210°F (100°C) or less. If you are pulling a load or going up hills, it is normal for the temperature to fluctuate and approach the 250°F (122°C) mark. If the gage reaches the 260°F (125°C) mark, it indicates that the cooling system is working beyond its capacity. See Engine Overheating on page 5-31. If your vehicle is a Two-mode Hybrid, see the Two-mode Hybrid manual for more information.