2006 Chevrolet Cobalt Owner's Manual - Page 144

Engine Coolant Temperature Warning Light The engine coolant temperature warning light will come on when the engine has overheated. Malfunction Indicator Lamp Check Engine Light Your vehicle is equipped with a computer which monitors operation of the fuel, ignition, and emission control systems. If this happens you should pull over and turn off the engine as soon as possible. See Engine Overheating on page 5-29 for more information. Notice: Driving with the engine coolant temperature warning light on could cause your vehicle to overheat. See Engine Overheating on page 5-29. Your vehicle could be damaged, and it might not be covered by your warranty. Never drive with the engine coolant temperature warning light on. This light will also come on when starting your vehicle. If it doesn't, have your vehicle serviced. 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. Notice: If you keep driving your vehicle with this light on, after awhile, 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 that may not be covered by your warranty. 3-32