Originally Posted by envoy03kmv
My 03 envoy was throwing the code for P0128 -Coolant Temp Below Thermostat Regulating Temp. I had changed the T-stat and it didnt help. symptoms are idling VERY high on 1st start in morning the colder the worse. and hard and long shifting in to gears ...i have to ease of the gas to help shift.(shifts fine if manually shifted) whats next? I am going to change the sensor tomorrow. Is that the next best step?
Where is it located? Any advise and tips would be awesome! thanks
Yes, it is the next best step. But before you change it I recommend you get ahold of a scan tool that shows ECT to see if it is actually malfunctioning. No need to repost. This post should be merged with your original we were helping you with because you are trying to solve the same thing. There are quite a few posts on the board that point out how to change the sensor.
The coolant temp sensor is located on the drivers side of the engine block directly above where the thermostat housing is. You will need to drain the coolant to change it. The only way to drain the coolant is to remove the lower radiator hose. If your hose is old you may want to change it at that time. So be prepaired with the new parts and 50/50 premix Dexcool in case it is your only vehicle.