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]









On Board Diagnosis Logic









DTC Confirmation Procedure

CAUTION:
Be careful not to overheat engine.

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

WITH CONSULT-III
1. Turn ignition switch ON.
2. Select "DATA MONITOR" mode with CONSULT-III.
3. Check that "COOLAN TEMP/S" indication 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 the following step.
4. Start engine and run it for 65 minutes at idle speed.
If "COOLAN TEMP/S" indication increases to more than 10�C (50�F) within 65 minutes, stop engine because the test result will be OK.
5. Check 1st trip DTC.
6. If 1st trip 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 screws on the body. Power Supply and Ground Circuit.










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. Component.
4.CHECK INTERMITTENT INCIDENT
Diagnosis Procedure. 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.