On my 1995 Sonata 2.0L DOHC manual, check engine light goes on intermitently (and stays on longer and longer). I read out the code that says Temperature coolant sensor is going bad (Typically first on will go after about a minute upon the start). I checked the sensor located on thermostat housing and it looks ok, it's resistance is in specified values on different temperatures. Then further reading says that ECM reads TWO sensors and compares temperatures and if they differ for more that 5 degrees the light will go on. Where is the second sensor. I could not find it. On thermostat housing there is 'temperature sender' to the left of the sensor (it is too NTC but has different value and checked ok). Now, on top of the thermostat housing there is what I believe is thermo switch, that seems to be always closed. What temperature it should be open and again
where is the second sensor. I appreciate if somebody could help me

 

 

NovarResource, thanks for the quick answer. I am confused. What is marked as 'Thermo sensor' appears to be a switch - it is on or off. Is this correct? Is there part number for it?

 

The Thermo Sensor is for operating the A/C system.


These are the coolant temp sensors for the PCM: