P0128 Saturn -

Question

My 2006 Saturn Ion 2 has code po128 the engine light come on sometime when driving and then it go of the engine is not over heating and the heater fan motor is blowing out hot air the engine is warming up quickly in the morning time what is causing the code po128?

Answer 1

P0128 Engine coolant temperature below thermostat regulating temperature

This is most the thermostat that does this Here is a P0128 that was caused by the seal of the thermostat.