I have a 2004 Gmc Envoy putting out a code of 0128 what does this mean?
This an engine coolant temperature fault, most likely caused by a defective thermostat, probably one that is open all the time.
In addition to the previous answer, check to see if your upper radiator hose is partially collapsed. If so that tells you that your thermostat maybe working correctly, but your radiator cap may be faulty. Worse case, take your thermostat off, boil water on the stove, drop thermostat in water after coming to a full boil. If thermostat opens, it's good. If not, I would replace the thermostat and the radiator cap.
842 views
Usually answered in minutes!
×