P0117
P0117, P0118 ECT SensorComponent Description
The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.
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CAUTION: Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis Logic
These self-diagnoses have the one trip detection logic.
P0117-P0118:
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode and the MIL illuminates.
DTC Confirmation Procedure
1. If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and wait at least 5 seconds.
3. Check DTC.
4. If DTC is detected, go to [P0117, P0118 ECT Sensor].
Diagnosis Procedure
Step 1-2:
Step 3-5:
Component Inspection
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.
[Reference data]
2. If NG, replace engine coolant temperature sensor.