P0128 Kia -

Question

I have replace the thermostat on my 2005 Kia Sedona twice in the past two years because of this engine code display.  I was told that it may be a bad sensor because when it does come on it goes off after a few days.  However, the temperature of the heater in winter is merely warm...never really gets hot so I am not sold on the idea that the thermostat is not somehow involved.  is it possible that the sensor is controlling the heater temperature.  And if so, where is this sensor located so we can replace.

Thank you for your advice.

Answer 1

P0128 Thermostat below regulating temperature

The sensor does not control the thermostat, The sensor only reports the condition, For the code condition P0128 KIA has produced a TSB about this code occurring. TSB # KT20008022101.  If the heater is not performing you have a thermostat problem, or problem with the heater core or the blend door for the heating/aircondition system.

 Poor heater condition can  be cause by low coolant level , and excessive rust creating a blockage to the heater core as well as overheat the engine