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 ECM is supplied to the ECTS via a resistor in the ECM. That is, the resistor in the ECM 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 ECM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve drivability.
ECM judges external signal input in condition that change of water temperature output value is over the 0.35v then ECM sets P0119.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, high
Poor connection
Short to ground in signal circuit
ECTS
Enable Conditions
-
Threshold value
? ECT sensor voltage > 0.35V
Diagnosis Time
6 sec
MIL On Condition
2 Driving Cycles
Temp. (?)
Resistance (k?)
-40
52.15
40
1.106
-20
16.52
60
0.5441
0
6.00
80
0.2889
20
2.45