2004 Buick Century Owner's Manual - Page 138

Tire Pressure Light The vehicle may have a tire pressure monitor that indicates a large change in the pressure in one tire. Malfunction Indicator Lamp Service Engine Soon Light Your vehicle is equipped with a computer which monitors operation of the fuel, ignition and emission control systems. The system stores the tire pressures of the vehicle's properly inflated tires. The LOW TIRE light will come on if the pressure in one tire becomes 12 psi (83 kPa) lower than the other three tires. The LOW TIRE light will not come on if the pressure in more than one tire is low, if the system is not yet calibrated, or if the vehicle is moving faster than 70 mph (110 km/h). When the LOW TIRE light comes on, stop as soon as possible and check all the tires for damage. If a tire is flat, see If a Tire Goes Flat on page 5-74. Also check the tire pressure in all four tires as soon as possible. See Inflation - Tire Pressure on page 5-64. The light will stay on, while the ignition is on, until the system is reset. See Tire Pressure Monitor System on page 5-65. This system is called OBD II (On-Board Diagnostics-Second Generation) and is intended to assure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment. The SERVICE ENGINE SOON light comes on and a chime will sound to indicate that there is a problem and service is required. Malfunctions often will be indicated by the system before any problem is apparent. This may prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. 3-36