2006 Pontiac Grand Prix Owner's Manual - Page 374

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 are under-inflated. 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. Re-check 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 Inflation Monitor System Your vehicle may have the Tire Inflation Monitor System (TIMS). The system is designed to alert the driver when there is a large air pressure change in one tire, while the vehicle is being driven. TIMS detects differences in tire rotation speeds that are caused by changes in tire pressure. The system can alert you about a low tire but it does not replace normal tire maintenance. See Tires on page 5-60. The TIMS learns the pressure at each tire throughout the operating speed range of the vehicle. The system normally takes between 45 and 90 minutes of driving to learn the tire pressures. This time may be longer depending on individual driving habits. Learning need not be accumulated during a single trip. Once learned, the system will remember the tire pressures until the system is reset. 5-68