2008 GMC Envoy Owner's Manual - Page 175

Tire Pressure Light Your vehicle has a tire pressure light. When the Light Flashes First and Then is Solid This indicates that there may be a problem with the Tire Pressure Monitor System. The light flashes for about a minute and stays on solid for the remainder of the ignition cycle. This sequence will repeat with every ignition cycle. See Tire Pressure Monitor System on page 5-67 for more information. Malfunction Indicator Lamp This light comes on briefly when the engine is started and provides information about tire pressures and the Tire Pressure Monitoring System. 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. When the Light is Solid This indicates that 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 3-53 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 5-57 for more information. 3-41