This can be caused by one of two things. First is the engine is actually running hot. This would show up on your temp gauge as the engine would be running hotter then 240deg. If the gauge or display shows normal engine temp then you may have a bad thermostat. The second problem is the thermostat, its performance is checked by the engine computer. If the thermostat is stuck open or opens too soon then the computer sets a code p0128. This may or may not set the check engine light to come on. If your check engine light is not on, there still may be a code set. The engine computer commands the hot engine light to come on as a default when this happens. You should check to see if there is a code set, most auto parts stores will do this for you for free. If you have the code p0128 set, then the thermostat is bad. This is covered under your 5yr 100k mile warranty so do not clear the code and take it to your local dealership to have it repaired.