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.
Checking the coolant temperature under detecting condition, if the coolant temperature exceeds the threshold temperature under normal operation loads, PCM sets P0217. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till cosecutive 2 driving cycle.
Item | Detecting Condition | Possible cause | |||||
DTC Strategy | ● Monitor the coolant temperature | ● ECTS | |||||
Enable Conditions | ● Coolant sensor is normal ● No disabling faults present(DTCs related to MAFS/MAPS, catalyst, fuel system or engine oil temperature sensor) ● Coolant Temperature at startup ＜ 45℃( 113 °F) ● Engine running state ● Coolant temperature ＞ 50℃( 122 °F) ● Intake air temperature ＜ 35℃( 95 °F) | ||||||
Thresh old value | ● Coolant temperature ≥ 110℃ (230 °F) (Average airflow＜30 g/sec and filtered airflow＜50 g/sec) | ||||||
Diagnosis Time | ● Once per driving cycle ( about 2 minutes) | ||||||
MIL On Condition | ● 2 driving cycles | ||||||
Temp. (℃/℉) | Resistance (kΩ) | Temp. (℃/℉) | 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 |
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Check DTC Status
Connect scantool to Data Link Connector(DLC).
IG "ON".
Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
Read "DTC Status" parameter.
Is parameter displayed "Present fault"?
▶ Go to "Component Inspection" procedure.
▶ Fault is intermittent, go to "Verification of vehicle Repair" procedure.
IG "OFF" and disconnect ECTS connector.
Remove it.
Measure resistance between terminals 1 and 3 of ECTS connector as the temperature rises.
Temp. (℃/℉) | Resistance (kΩ) | Temp. (℃/℉) | 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 |
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Are the measured resistance within specification?
▶ Clear DTC and Test-drive under enable conditions above-mentioned. After the test, If this DTC is set, recheck it thoroughly. If not, it is intermittent fault, go to "Verification of vehicle Repair" procedure.
▶ Substitute with a known - good ECTS and check for proper operation.
▶ If the problem is corrected, Go to "Verification of Vehicle Repair"procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
Read "DTC Status" parameter
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
▶ Go to the applicable troubleshooting procedure.
