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.
DTC Logic
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE 1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.
Turn ignition switch OFF and wait at least 10 seconds.
Turn ignition switch ON.
Turn ignition switch OFF and wait at least 10 seconds. >> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
Turn ignition switch ON and wait at least 5 seconds.
Check DTC. Is DTC detected?
YES >> Go to Diagnosis Procedure.
NO >> Inspection END
YES >> GO TO 2.
NO >> Repair or replace ground connection. 2.CHECK ECT SENSOR POWER SUPPLY CIRCUIT
Disconnect engine coolant temperature (ECT) sensor harness connector.
Turn ignition switch ON.
Check the voltage between ECT sensor harness connector and ground.
Is the Inspection result normal?
YES >> GO TO 3.
NO >> Repair open circuit, short to ground or short to power in harness or connectors. 3.CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
Turn ignition switch OFF.
Disconnect ECM harness connector.
Check the continuity between ECT sensor harness connector and ECM harness connector.
Also check harness for short to ground and short to power. Is the Inspection result normal?