The problem is with your electric fan clutch assy. You may need to have it replaced. There is also a reprogram available for your pcm to change the parameters for this failure, it basically makes the system less sensitive. Go to your local GM dealership to see if your veh has the updated pcm software or not. If the reprogram doesn't work you will have to replace the fan clutch assy. Since it is electric it is expensive at $500+. This is something you have to repair or your veh will not pass an emissions inspection since the check engine light will be illuminated.
Source: GM Certified Technician