INSPECT ENGINE COOLANT TEMPERATURE SENSOR
CHECK ENGINE COOLANT TEMPERATURE SENSOR (OPEN IN SENSOR)
CHECK HARNESS AND CONNECTOR (ECT SENSOR - ECM)
CHECK ENGINE COOLANT TEMPERATURE SENSOR (SHORT IN SENSOR)
CHECK HARNESS AND CONNECTOR (ECT SENSOR - ECM)
DTC P0115 Engine Coolant Temperature Circuit |
DTC P0117 Engine Coolant Temperature Circuit Low Input |
DTC P0118 Engine Coolant Temperature Circuit High Input |
DESCRIPTION
A thermistor is built into the Engine Coolant Temperature (ECT) sensor and it changes its resistance value according to the engine coolant temperature.The structure of the sensor and connection to the ECM is the same as the intake air temperature sensor.
- HINT:
- If the ECM detects the DTC P0115, P0117, or P0118, it operates the fail-safe function in which the ECT is assumed to be 80°C (176°F).
| DTC No. | DTC Detection Condition | Trouble Area |
| P0115 | Open or short in ECT sensor circuit for 0.5 seconds (1 trip detection logic) |
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| P0117 | Short in ECT sensor circuit for 0.5 seconds (sensor resistance value less than 79 Ω) (1 trip detection logic) |
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| P0118 | Open in ECT sensor circuit for 0.5 seconds (sensor resistance value more than 156 kΩ) (1 trip detection logic) |
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- HINT:
- When DTC P0115, P0117, and/or P0118 is detected, check the engine coolant temperature by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Coolant Temp.
| Temperature Displayed | Malfunction |
| -40°C (-40°F) | Open circuit |
| 140°C (284°F) or more | Short circuit |
WIRING DIAGRAM
INSPECTION PROCEDURE
- NOTICE:
- After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).
| 1.INSPECT ENGINE COOLANT TEMPERATURE SENSOR |
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
Read the value.
- OK:
- 75 to 95°C (167 to 203°F) after warming up the engine.
- Result:
Temperature Displayed Proceed to -40°C (-40°F) A 140°C (284°F) or more B OK (Same as actual engine coolant temperature) C
- HINT:
- If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
- If there is a short circuit, the intelligent tester indicates 140°C (284°F) or more.
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| A | |
| 2.CHECK ENGINE COOLANT TEMPERATURE SENSOR (OPEN IN SENSOR) |
Disconnect the E40 ECT sensor connector.
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Connect terminals 1 and 2 of the ECT sensor wire harness side connector.
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
Read the value.
- Standard:
- 140°C (284°F) or more
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| NG | |
| 3.CHECK HARNESS AND CONNECTOR (ECT SENSOR - ECM) |
Disconnect the E40 ECT sensor connector.
 |
Disconnect the E59 ECM connector.
Measure the resistance.
- Standard resistance:
Tester Connections Specified Conditions THW (E40-2) - THW (E59-111) Below 1 Ω E2 (E40-1) - ETHW (E59-88)
Reconnect the ECT sensor connector.
Reconnect the ECM connector.
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| OK | ||
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| 4.CHECK ENGINE COOLANT TEMPERATURE SENSOR (SHORT IN SENSOR) |
Disconnect the E40 ECT sensor connector.
 |
Connect the intelligent tester to the DLC3.
Turn the engine switch ON (IG) and turn the intelligent tester ON.
Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.
Read the value.
- Standard:
- -40°C (-40°F)
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| NG | |
| 5.CHECK HARNESS AND CONNECTOR (ECT SENSOR - ECM) |
Disconnect the E40 ECT sensor connector.
 |
Disconnect the E59 ECM connector.
Measure the resistance.
- Standard resistance:
Tester Connection Specified Condition THW (E40-2) or THW (E59-111) - Body ground 10 kΩ or higher
Reconnect the ECT sensor connector.
Reconnect the ECM connector.
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| OK | ||
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