2003 GMC Savana Van Owner's Manual - Page 155

Low Coolant Warning Light Malfunction Indicator Lamp Check Engine Light LOW COOLANT States United 7 Yourvehicle CHECK is equipped with a computer which monitors operation of the fuel, ignition and emission control systems. This message is displayed when the cooling system is low on coolant. The engine may overheat. See Engine Coolant on page 5-24 and have your vehicle serviced as soon as you can. 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. Notices If you keep driving your vehicle with this light on, after a while, your emission controls may not work as well, your fuel economy may not be as good and your engine may not run as smoothly. This could lead to costly repairs thatmay not be covered by your warranty. 3-34