Hey guys,

So my truck has a CEL I pulled the code and i got P0128.Now i know the code is basically saying that my truck isn't reaching the operating temperature. So i was thinking of changing the thermostat since i have a feeling it might be stuck open but i have also heard that it can be the sending unit.

Now my question is which would you guys recommend i change first or which is more likely to be causing the problem?

 

i would go with the thermostat first. They are fairly cheap and not hard to put in.

 

yeah that was the way i was leaning towards and its what i will do i just wanted to ask in case someone had encountered the same issue.

 

that p0128 may have caused your truck to throw that p0316 on your other post.

 

should be the thermostat same code was thrown in my truck, replaced the thermostat and no problems since.

 

i would do the thermostat and flush the cooling system

 

Before you throw a part at it you can always do a little diagnostics to see if it's the sensor or the thermostat. Take the truck for a little ride then turn the heat on high, if you have no or low heat it's the thermostat if you have good heat it's the sensor.

 

Well i changed the thermostat yesterday. I picked up one from napa and so far so good. The old thermostat didn't seem to be bad or anything but now with the new thermostat the temperature gauge reads right in the middle. Before it would be about 1/4 up from Cold. It idles smoother than before now and so far no CEL light.