2002 Pontiac Bonneville Owner's Manual - Page 343

When to Check Check your tires once a month or more. Don't forget your compact spare tire. It should be at 60 psi (420 kPa). How to Check Use a good quality pocket-type gage to check tire pressure. You can't tell if your tires are properly inflated simply by looking at them. Radial tires may look properly inflated even when they're underinflated. Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture. The CHECK TIRE PRESSURE message will appear on the Driver Information Center (DIC) or the system monitor TIRE PRESS light will come on if pressure difference (low pressure) is detected in one tire. The check tire pressure system may not alert you if: D D D D D D D more than one tire is low, the vehicle is moving faster than 65 mph (105 km/h), the system is not yet calibrated, the tire treadwear is uneven, the compact spare tire is installed, tire chains are being used, or the vehicle is being driven on a rough or frozen road. Check Tire Pressure System The check tire pressure system can alert you to a large change in the pressure of one tire. The system won't alert you before you drive that a tire is low or flat. You must begin driving before the system will work properly. If the anti-lock brake system warning light comes on, the check tire pressure system may not be working properly. See your dealer for service. Also, see "Anti-Lock Brake System Warning Light" in the Index. The check tire pressure system 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 doesn't replace normal tire maintenance. See "Tires" in the Index. 6-48