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>

*: These data are reference values and are measured between ECM terminals 46 (Engine coolant temperature sensor) and ground.

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.

DTC Logic

DTC DETECTION LOGIC

NOTE: If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117, P0118. Refer to EC-186, "DTC Logic".

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

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

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine and warm it up to normal operating temperature.

2. Rev engine up to 2,000 rpm for more than 10 minutes.

3. Move the vehicle to a cool place, then stop engine and turn ignition switch OFF.

4. Check resistance between “fuel level sensor unit and fuel pump” terminals 4 and 5.

5. Soak the vehicle until the resistance between “fuel level sensor unit and fuel pump” terminals 4 and 5 becomes 0.5 kΩ higher than the value measured before soaking.

CAUTION: Never turn ignition switch ON during the soaking time.

NOTE: Soak time changes depending on ambient air temperature. It may take several hours.

6. Start engine and let it idle for 5 minutes.

7. Check 1st trip DTC.

Is 1st trip DTC detected? YES >> EC-185, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to GROUND INSPECTION in GI-45, "Circuit Inspection".

Is the inspection result normal? YES >> GO TO 2.

NO >> Repair or replace ground connection.

2.CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to EC-185, "Component Inspection".

Is the inspection result normal? YES >> GO TO 3.

NO >> Replace engine coolant temperature sensor.

3.CHECK INTERMITTENT INCIDENT

Refer to GI-42, "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.

4. Check resistance between engine coolant temperature sensor terminals as follows.

Is the inspection result normal? YES >> INSPECTION END

NO >> Replace engine coolant temperature sensor.