DTC P0115 Engine Coolant Temperature Circuit Malfunction
DTC P0117 Engine Coolant Temperature Circuit Low Input
DTC P0118 Engine Coolant Temperature Circuit High Input
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Read value using intelligent tester (engine coolant temperature)
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Read value using intelligent tester (check for open in wire harness)
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Check harness and connector (engine coolant temperature sensor - ecm)
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Read value using intelligent tester (check for short in wire harness)
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Check harness and connector (engine coolant temperature sensor - ecm)
Description
A thermistor, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor. The structure of the sensor and its connection to the ECM are the same as those of the intake air temperature sensor.
HINT:
When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.
DTC No. | DTC Detection Condition | Trouble Area |
P0115 | Open or short in engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic). |
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P0117 | Short in engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic). |
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P0118 | Open in engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic). |
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HINT:
When any of these DTCs are set, check the engine coolant temperature by entering the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
Temperature Displayed | Malfunction |
-40°C (-40°F) | Open circuit |
140°C (284°F) | Short circuit |
Monitor description
The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature becomes low, the resistance in the thermistor increases. When the temperature becomes high, the resistance drops. These variations in resistance are reflected in the output voltage from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the engine coolant temperature sensor circuit and sets a DTC.
Monitor strategy
Frequency of Operation | Continuous |
Confirmation driving pattern
- Turn the power switch on (IG) and wait for 0.5 seconds or more.
Wiring diagram

Inspection procedure
HINT:
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
1.READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE) |
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Connect the intelligent tester to the DLC3.
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Turn the power switch on (IG).
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
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Read the value displayed on the tester.
Standard Value:
Between 75°C and 100°C (167°F and 212°F) with warm engine.
Result Result Proceed to -40°C (-40°F) A 140°C (284°F) B Between 75°C and 100°C (167°F and 212°F) C HINT:
- If there is an open circuit, the tester indicates -40°C (-40°F).
- If there is a short circuit, the tester indicates 140°C (284°F).
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OK | |
2.READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS) |
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Disconnect the engine coolant temperature sensor connector.
Text in Illustration *1 Engine Coolant Temperature Sensor *2 ECM *a Front view of wire harness connector (to Engine Coolant Temperature Sensor) - -
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Connect terminals 1 and 2 of the engine coolant temperature sensor connector on the wire harness side.
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Connect the intelligent tester to the DLC3.
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Turn the power switch on (IG).
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
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Read the value displayed on the tester.
Standard Value:
140°C (284°F)
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OK | |
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3.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) |
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Disconnect the engine coolant temperature sensor connector.
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition D6-2 - D27-64 (THW) Always Below 1 ? D6-1 - D27-65 (ETHW) Always Below 1 ?
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OK | |
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4.READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) |
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Disconnect the engine coolant temperature sensor connector.
Text in Illustration *1 Engine Coolant Temperature Sensor *2 ECM
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Connect the intelligent tester to the DLC3.
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Turn the power switch on (IG).
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
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Read the value displayed on the tester.
Standard value:
-40°C (-40°F)
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OK | |
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5.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) |
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Disconnect the engine coolant temperature sensor connector.
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition D6-2 or D27-64 (THW) - Body ground Always 10 k? or higher
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OK | |
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