2008 GMC Sierra 1500 Pickup Owner's Manual - Page 180

Tire Pressure Light This light comes on briefly when the engine is started. Malfunction Indicator Lamp Check Engine Light A computer system called OBD II (On-Board Diagnostics-Second Generation) monitors operation of the fuel, ignition, and emission control systems. It makes sure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment. The check engine light comes on to indicate that there is an OBD II problem and service is required. 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 3-59 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 5-58 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 5-66 for more information. Malfunctions often are indicated by the system before any problem is apparent. This can prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. 3-44