P0117

P0117, P0118 ECT SENSOR

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]







DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


1. PRECONDITIONING

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.
- GO TO 2.

2. PERFORM DTC CONFIRMATION PROCEDURE

1.Turn ignition switch ON and wait at least 5 seconds.
2.Check DTC.
Is DTC detected?
YES- Go to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK GROUND CONNECTION

1.Turn ignition switch OFF.
2.Check ground connection M95. Refer to Ground Inspection in "Circuit Inspection" Circuit Inspection.
Is the inspection result normal?
YES- GO TO 2.
NO- Repair or replace ground connection.

2. CHECK ECT SENSOR POWER SUPPLY CIRCUIT

1.Disconnect engine coolant temperature (ECT) sensor harness connector.
2.Turn ignition switch ON.
3.Check the voltage between ECT sensor harness connector and ground.





Is the inspection result normal?
YES- GO TO 3.
NO- Repair or replace error-detected parts.

3. CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
3.Check the continuity between ECT sensor harness connector and ECM harness connector.





4.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 4.
NO- Repair open circuit, short to ground or short to power in harness or connectors.

4. CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to "Component Inspection" .
Is the inspection result normal?
YES- GO TO 5.
NO- Replace engine coolant temperature sensor. Refer to "Exploded View" Exploded View.

5. CHECK INTERMITTENT INCIDENT

Refer to "Intermittent Incident" Intermittent Incident.
- INSPECTION END


Component Inspection


1. CHECK ENGINE COOLANT TEMPERATURE SENSOR

1.Turn ignition switch OFF.
2.Disconnect engine coolant temperature sensor harness connector.
3.Remove engine coolant temperature sensor. Refer to "Exploded View" Exploded View.





4.Check resistance between engine coolant temperature sensor terminals by heating with hot water as shown in the figure.





Is the inspection result normal?
YES- INSPECTION END
NO- Replace engine coolant temperature sensor. Refer to
"Exploded View" Exploded View.