The Engine Coolant Temperature(ECT) Sensor measures the temperature of engine coolant. The Engine Coolant Temperature (ECT) Sensor is located near the thermostat housing of the cylinder head. ECT Sensor is a thermistor (A Variable Resistor that Changes Along with ECT) in series with a fixed resistor in the Engine Control Module (ECM). The ECM applies 5 volts to the ECT sensor. The ECM monitors the voltage across the ECT sensor and converts it into a temperature reading. When the engine is cold the ECT sensor resistance is high, and when the engine is warm the ECT sensor resistance is low. Therefore, when the engine is cold the ECM will receive a high voltage input, and when the engine is warm the ECM will receive a low voltage input. The signal from ECT sensor is used for Injection control, ignition timing, idle speed and cooling fan control.
If there is no Engine Coolant Temperature Sensor signal change during driving, ECM sets this code(P0116).
Item
Detecting Condition
Possible Cause
DTC Strategy
Rationality check
Poor connection
ECTS
Enable Conditions
Cold driving condition = 2 times, or Hot driving condition = 2 times
Threshold Value
ECT signal change(Max. – Min.) < 0.8~3.0°C
Diagnostic Time
-
MIL ON Condition
3 driving cycle
Temperature [°C (°F)]
Resistance [kO]
-40(-40)
48.14
-20(-4)
14.13~16.83
0(32)
5.79
20(68)
2.31~2.59
40(104)
1.15
60(140)
0.59
80(176)
0.32