Turn it OFF for 10 seconds and restart. IF the refer does NOT start a cool down cycle and get to a normal operating temp, you will get a NO CO code. The odds are, your rear fans(2) are NOT running and that is why you have your problem. Please respond ---Is this refer in a slide room? If so, THAT will definitely cause a cool down problem as the fans are required to properly exhaust the hot air. IF you have a failed Cooling unit, then the Red LED will come on. You can get a small 120 volt fan(regular countertop type fan) and remove the outside access refer door and wedge that fan blowing UP. That will be enough to simulate the regular fans and see if the refer then cools correctly. If so, then the refer will have to be pulled and the fans AND the fan tstat will need to be replaced. Since it was running then stopped and you did NOT trip the recall control, I will bet the fans are at fault. A NO CO will usually not trip if the refer was at temp and then something stopped the cooling and the temp raised. A NO CO only happens when the refer starts at a normal ambient temp and then starts a cool down and never reaches its set temp. It stops and then the temp stabilizes at above 45 or higher or the refer starts a temp rise before reaching the set temp. Your refer is 8 years old and that is about the life span of the fans and fan tstat. Doug