The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5 V in the PCM is supplied to the ECTS via a resistor in the PCM. That is, the resistor in the PCM and the thermistor in the ECTS are connected in series. When the resistance value of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. During cold engine operation the PCM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve drivability.
If measured temperature is lower than the minimum threshold value, PCM sets DTC P0118.
(In this case, the input signal voltage is the maximum threshold vaue.)
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, high
Poor connection
Open or short to power in signal circuit
Open in ground circuit
ECTS
Enable Conditions
-
Threshold value
ECTS's voltage > 3.28V
Diagnosis Time
2 sec
MIL On Condition
2 Driving Cycles
Temp. (?)
Resistance (k?)
-40
48.14
40
1.15
-20
14.13 ~ 16.83
60
0.59
0
5.79
80
0.32
20
2.31 ~ 2.59
100
0.19