My car is giving me a code PO 128 at startup?

Question

From what I read, code 128 means the coolant temp hasn't reach a certain temp AFTER a period of time. But mine has come on the first startup . First time I restarted and light went out, but now on all the time.Temp gauge reads were it always have after a few minutes, heater works great, and car has no performance problems. Coolant level good and has just been replaced couple months ago.

Answer 1

P0128 Coolant temperature below operating temperature

P0128 is the thermostat, a lot of thermostat on the market are now fail safe equipt which means  it does not stay shut would would overheat the engine and cause more problems which is a good thing, 2 thing , this can be intermittent due to the servcie and change of the cooling system. That or the coolant thermostat, You can clear the code if P0128 returns just replace the thermostat.