2006 GMC Yukon Owner's Manual - Page 438

How to Check Use a good quality pocket-type gage to check tire pressure. You cannot tell if your tires are properly inflated simply by looking at them. Radial tires may look properly inflated even when they're underinflated. Check the tire's inflation pressure when the tires are cold. Cold means your vehicle has been sitting for at least three hours or driven no more than 1 mile (1.6 km). Remove the valve cap from the tire valve stem. Press the tire gage firmly onto the valve to get a pressure measurement. If the cold tire inflation pressure matches the recommended pressure on the Tire and Loading Information label, no further adjustment is necessary. If the inflation pressure is low, add air until you reach the recommended amount. If you overfill the tire, release air by pushing on the metal stem in the center of the tire valve. Recheck the tire pressure with the tire gage. Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture. Tire Pressure Monitor System The Tire Pressure Monitor System (TPMS) uses radio and sensor technology to check tire pressure levels. If your vehicle has this feature, sensors are mounted on each tire and wheel assembly, except the spare tire. The TPMS sensors monitor the air pressure in your vehicle's tires and transmit tire pressure readings to a receiver located in the vehicle. The TPMS is designed to alert the driver, if a low tire pressure condition exists. This system also allows the driver to check tire pressure levels using the Driver Information Center (DIC). When a low tire pressure condition is detected, the TPMS displays the CHECK TIRE PRESSURE warning message on the DIC, and at the same time illuminates the low tire pressure warning symbol. For additional information and details about the DIC operation and displays see DIC Operation and Displays on page 3-53 and DIC Warnings and Messages on page 3-56. You may notice, during cooler weather conditions, that the tire pressure monitor light, located on the instrument panel cluster, and the CHECK TIRE PRESSURE message will appear when the vehicle is first started and then turn off as you start to drive the vehicle. This could be an early indicator that the tire pressures are getting low and need to be inflated to the proper pressure. 5-64