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.
Checking output signals from ECTS every 120 sec. under detecting condition, if an output signal is below 0.1V for more than 4 sec., PCM sets P1114.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● This code detects a intermittent short to ground in the signal circuit or the sensor | ● Poor Connection ● Short to ground in signal Circuit ● Faulty ECTS ● Faulty PCM |
Enable Conditions | Case 1 | ● Engine Running Time > 120sec. |
Case 2 | ● Soak Time > 360min. ● Engine Running | |
Threshold value | ● Coolant signal < 0.1V | |
Diagnosis Time | ● Continuous (More than 4 sec. failure for every 120 sec. test) | |
MIL On Condition | ● DTC only (NO MIL ON) |
Temp. (°C/°F) | Resistance (kΩ) | Temp. (°C/°F) | Resistance (kΩ) |
-40(-40) | 48.14 | 40(104) | 1.15 |
-20(-4) | 14.13 ~ 16.83 | 60(140) | 0.59 |
0(32) | 5.79 | 80(176) | 0.32 |
20(68) | 2.31 ~ 2.59 |
