2006 GMC Envoy Q&A
2006 GMC Envoy Question: i replaced the thermostat and i am still setting p0128 code.what next.
The scan tool i have will not read sensors or tell me anything other than the code that has been set. i don't want to go to a mechanic and would like to know the most likely problem causing this code. i am not the one driving the car and am not sure when and under what conditions the code is being set, i think it is happening after the car is warmed up and been driven a while. - teslafan
If you were able to read data, the temperature sensor needs to be monitored. And by the way, we are Technicians/Mechanics. - ProfessorG
Could also be that water temperature sensor is not working right. - Dr Quick