ECTS (Engine Coolant Temperature Sensor) located in the engine coolant passage of the cylinder head.
It detects the water temperature and relays signals to the ECM.
It employs a thermistor, which is sensitive to the changes in the coolant temperature.
The electric resistance of a thermistor decreases as the fuel temperature increases, and increases as the fuel temperature decreases.
The power source in the ECM is supplied to the ECTS via a resistor in the ECM.
The electric resistance of a thermistor decreases in response to the temperature rise.
The ECM judges engine coolant temperature by sensor output voltage and provides optipum fuel enrichment when the engine is cold and in order to operate the radiator fan and the A/C condensor fan.
If the signal exceeds threshold value, the ECM judged this as a fault and DTC is set.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Signal check, high | ● Short to battery in signal circuit ● Open in signal circuit ● Open in ground circuit ● Faulty ECTS ● Faulty ECM |
Enable Conditions | ● Ignition on | |
Threshold Value | ● Output signal > 4.97 V | |
Diagnostic Time | ● 0.5 sec. | |
MIL Fuel Limit Fuel Cut EGR Off | ● No ● No ● No ● Yes | |
Fail safe | ● Engine temp. is fixed value of 80°C after cranking and -25°C when cranking by ECM. ● Engine performance is reduced over 120°C ● Radiator cooling fan and A/C condensor fan is operated. ● Air conditioning system deactivation ● Water heater deactivation |
ECTS | ||
Temperature (°C) | 20 | 80 |
Resistance (kΩ) | 2.31 ~ 2.59 | 0.31 ~ 0.33 |
