CTS (Coolant Temperature Sensor), THw (Thermistor water), ECT (Engine Coolant Temperature)

Specifications:

Q. Does the sensor meet the manufacturer's specifications why or why not?
A. Yes it meets the manufacturer's specifications because it is working properly.
Q. What type of thermistor is this?
A. Negative Temperature Coefficient (NTC), Changes it resistance depending on temperature. As temperature increases, resistance of a NTC will decrease.

Q. Explainn the internal operation of the sensor
A. The thermistor has two terminals, one for power and one for ground. A reference voltage is supplied to one terminal through a fixed series resistor located inside the computer. The other terminal of the themistor is connected to ground, usually back through the computer. The computer monitor the voltage after the internal fixed resistor and compares this voltage to the reference voltage to determine the temperature of the thermistor. The relationship between the two voltages changes as the temperature of the thermistor changes. (Toyota Sensors and Actuators)
As the themperature of water increases, the resistance of the sensor decreases beacuse of NTC type thermistor. The changes in resistance of thermistor, results in changes in voltage to the ECU. ECU then processes the voltages and matches these voltages with internal reference map and send the signal accordingly to the actuators.