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.
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
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 "COOLANT 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 "COOLANT 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. Refer to Power Supply and Ground Circuit.
OK or NG
OK - GO TO 2.
NG - Repair or replace ground connections.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to 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. Refer to Component.
4.CHECK INTERMITTENT INCIDENT
Refer to Diagnosis Procedure. Refer to 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.
2. If NG, replace engine coolant temperature sensor.
Removal and Installation
ENGINE COOLANT TEMPERATURE SENSOR
Refer to Component.