2007 Pontiac Grand Prix Owner's Manual - Page 180

Engine Coolant Temperature Gage The vehicle has a gage that shows the engine coolant temperature. Malfunction Indicator Lamp Check Engine Light Your vehicle has a computer which monitors operation of the fuel, ignition, and emission control systems. 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 check engine light comes on 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. If the gage pointer moves into the shaded area, the engine is too hot. That reading means the engine coolant has overheated. If you have been operating the vehicle under normal driving conditions, you should pull off the road, stop the vehicle, and turn off the engine as soon as possible. See Cooling System on page 366 for more information. 180