Component Location
Description
1. 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.
2. DTC Description
The ECM sets DTC P0116 when the variation of measured engine coolant temperature from engine start is smaller than threshold while variation of calculated coolant temperature by ECM is greater than threshold.
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
Monitoring Strategy | ? Rathionality check | ? Poor connections ? Faulty IATS ? Faulty ECM ? Faulty ETCS ? Contaminated, deterriorated or damaged ETCS ? Faulty thermostat. |
Threshold value | 1 | ? High side check ? Coolent temperature at IG SW off ? Coolent temperatuer(not filtered) : < 9.75?(49.55?) |
2 | ? Stuck signal ? Tmmax - tmmin : <3.0?(37.4?) |
3 | ? Low side not plausible ? Coolant temperature(filtered) : > 10?(50?) ? Coolant temperture at IG SW off |
4 | ? Cut in lambda control ? Coolent temperature(not filtered) : < TMLRTMS |
Enable Conditions | 1 | ? Soak time : > 65000s ? Coolent temperature at IG SW off : > 60?(140?) |
2 | ? High radiation & low radiation : 2times |
3 | |
4 | ? Warm up waiting time : = 0.0 |
Diagnostic Time | |
MIL on condition | ? 0 .5 sec |
If any codes relating to ECTS, IATS circuits are present,do all repairs associated with those codes before proceeding with this troubleshooting procedure.
Specification
Service standard |
When ECT is 0? (32?) : 3.7~4.3 V |
When ECT is 20?(68?) : 3.2~3.6 V |
When ECT is 40?(104?) : 2.4~3.05 V |
When ECT is 80?(176?) : 1.0~1.5 V |
Specification
Service standard |
When ECT is 0? (32?) : 3.7~4.3 V |
When ECT is 20?(68?) : 3.2~3.6 V |
When ECT is 40?(104?) : 2.4~3.05 V |
When ECT is 80?(176?) : 1.0~1.5 V |
Schematic Diagram
Signal Waveform
ECTS output is in inverse proportion to water temperature changes. This figure shows the waveform at terminal 4 of ECTS at idle rpm.
In case the voltage of ECTS is always 4V.
Possible cause : Open ground circuit. Open inner circuit of component. |
In case,when engine is cold,the voltage is below 0.5V
Possible cause :Short between ECM and sensor Faulfy ECM |
Is Sensor Switching Properly
If the output voltage moves in reverse direction while water temperature changes,the ECT sensor is normal.
In case there is no symptom and wrong data but DTC is shown |
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes |
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure. Go to "Terminal and Connector inspection" procedure. |
In case there is symptom and wrong data with DTC |
Check open,short or connector’s connection for ECTS. |
Check the deterioration of ECTS performance. Go to "Visual/Physical inspection" procedure. |
Signal Waveform
This figure shows the waveform at terminal 4 of ECTS at idle rpm.
In case the voltage of ECTS is always 4V.
Possible cause : Open ground circuit Open inner circit of component |
In case,when engine is cold,the voltage is below 0.5V
Possible cause :Short between ECM and sensor, Faulty ECM |