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COMPONENT LOCATION

GENERAL DESCRIPTION

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.

DTC DESCRIPTION

ECM sets DTC P0116 if the ECM detects stuck low, high or implausible high ECT signal

DTC DETECTING CONDITION

Item		Detecting Condition ＆ Fail Safe	Possible Cause
DTC Strategy	case 1)	● Signal stuck Low	● Contact resistance in connections. ● Insufficient Engine Coolant ● Faulty Thermostat ● Faulty ECT sensor
DTC Strategy	case 2)	● Signal stuck High
Enable Conditions	case 1)	● No relevant failure ● 6 ＜ Battery voltage ＜ 16V
Enable Conditions	case 2)	● No relevant failure ● Engine oil temp. at engine stop of previous DC ＞ 70℃(158℉) ● Coolant temp. at engine stop of previous driving cycle ＞ 70℃(158℉) ● Engine oil temperature at Start ＜ 35℃(95℉) ● Intake Air Temperature at Start ＜ 35℃(95℉)
Threshold Value	case 1)	● Coolant temperature signal variation since engine start ＜ 2℃(4℉) when coolant temp. below 40℃(104℉) at start
Threshold Value	case 2)	● Engine coolant temperature at start ＞ 53℃(127℉)
Diagnostic Time	case 1)	● 10~30 minutes depends on coolant temp. at start
Diagnostic Time	case 2)	● Immediate
Mil On Condition		● 2 Driving Cycles

SIGNAL WAVEFORM AND DATA

SPECIFICATION

Temp.(℃)	Temp.(℉)	Resistance(㏀)
-20	-4	14.1 ~ 16.8
0	32	Approx. 5.8
20	68	2.3 ~ 2.6
40	104	Approx. 1.2
60	140	Approx. 0.6
80	176	Approx. 0.3

SCHEMATIC DIAGRAM

MONITOR DTC STATUS

note

If any DTCs relating to ECTS are stored, do ALL REPAIRS associated with those codes before proceeding with further troubleshooting

Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.

Press F4(DTAL) to select DTC information from the DTCs menu.

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"?

note

History (Not Present) fault : DTC occurred but has been cleared.

Present fault : DTC is occurring at present time.

▶ Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

▶ Go to next step as below.

MONITOR SCANTOOL DATA

Allow the engine to cool completely

Run the cold engine at idle for 5 minutes and observe cooling fan status.

note

Ensure that the A/C is OFF

Check the engine coolant temperature parameter at idle with the scantool.

Is the engine coolant temperature increase to above 50℃(122℉)

▶ Go to "Terminal and Connector Inspection" procedure

▶ Go to next step as below

▶ Are the cooling fans running when engine coolant temperature is low(less than approximately 98℃(208℉)) with A/C OFF?

▶ Check for short circuit in cooling fan harness or cooling fan relay. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

With ignition "ON", Install scantool and select "COOLING FAN RELAY" on the Actuation Test mode.

Activates "COOLING FAN RELAY" by pressing "STRT(F1)" key

Repeat this procedure 4 or 5 times to ensure cooling fan reliability.

If cooling fan works properly, go to next step as below

If NG, check for intermittent fault caused by poor contact in the sensor's and/or ECM's connector. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

TERMINAL AND CONNECTOR INSPECTION

Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.

▶ Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure

SYSTEM INSPECTION

Coolant Level Inspection

(1)

Check the cooling system coolant level.

(2)

Is the coolant in the reservoir at the proper level?

▶ Go to next step as below

▶ Repair or add engine coolant as necessary and go to "Verification of Vehicle Repair" procedure

Thermostat Inspection

(1)

Check if the thermostat bypass valve is stuck in the open position or if the correct type of thermostat was installed. Replace thermostat as necessary and go to "Verification of Vehicle Repair" procedure

(2)

Check the valve opening temperature of the thermostat

Specification(Valve opening temperature) : 80~84℃(176~183℉):

(3)

If the opening temperature is not as specified, Replace thermostat as necessary and go to "Verification of Vehicle Repair" procedure.

If OK, go to next step as below.

ECT Sensor Inspection

(1)

Ignition "OFF"

(2)

Disconnect ECTS connector

(3)

Measure resistance between terminals 1 and 3 of the sensor connector(Component side)

Specification :

Temp.(℃)	Temp.(℉)	Resistance(㏀)
-20	-4	14.1 ~ 16.8
0	32	Approx. 5.8
20	68	2.3 ~ 2.6
40	104	Approx. 1.2
60	140	Approx. 0.6
80	176	Approx. 0.3

(4)

Is resistance within the specification?

▶ Go to next step as below.

▶ Check ECTS for contamination, deterioration, or damage. Substitute with a known-good ECTS and check for proper operation. If the problem is corrected, replace ECTS and then go to "Verification of Vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR

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.