P0125

DTC P0125 ECT SENSOR





Component 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.





[Reference data]






CAUTION:
Do not 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

NOTE:
- If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or P0118. P0117.
- If DTC P0125 is displayed with P0116, first perform the trouble diagnosis for DTC P0116. P0125.









DTC Confirmation Procedure

CAUTION:
Be careful not to overheat engine.

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

WITH CONSULT-III
1. Turn ignition switch ON.
2. Select "DATA MONITOR" mode with CONSULT-III.
3. Check that "COOLAN TEMP/S" is above 10�C (50�F).
If it is above 10�C (50�F), the test result will be OK.
If it is below 10�C (50�F), go to following step.
4. Start engine and run it for 65 minutes at idle speed.
If "COOLAN TEMP/S" increases to more than 10�C (50�F) within 65 minutes, stop engine because the test result will be OK.
5. Check DTC.
6. If DTC is detected, go to P0125.

WITH GST
Follow the procedure "WITH CONSULT-III" above.




Diagnosis Procedure
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body. Ground Inspection.










OK or NG
OK - GO TO 2.
NG - Repair or replace ground connections.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR
P0125.
OK or NG
OK - GO TO 3.
NG - Replace engine coolant temperature sensor.
3.CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70�C (158�F)] condition, grasp lower radiator hose and confirm the engine coolant does not flow.
OK or NG
OK - GO TO 4.
NG - Repair or replace thermostat. Removal and Installation.
4.CHECK INTERMITTENT INCIDENT
P0117.
- INSPECTION END




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.




Removal and Installation

ENGINE COOLANT TEMPERATURE SENSOR
Component.