Nissan Maxima Service and Repair Manual: P0116 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>

*: These data are reference values and are measured between ECM terminals 46 (Engine coolant temperature sensor) and 52 (Sensor ground).

DTC Logic

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.INSPECTION START

2.PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to EC-202, "Component Function Check".

NOTE: Use the component function check to check the overall function of the ECT sensor circuit. During this check, a 1st trip DTC might not be confirmed.

3.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.

TESTING CONDITION:

•  Before performing the following procedure, do not add fuel.
•  Before performing the following procedure, check that fuel level is between 1/4 and 4/4.
•  Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.

4.PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine and let it idle for 60 minutes.
2. . Move the vehicle to a cool place. NOTE: Cool the vehicle in an environment of ambient air temperature between −10C (14F) and 35C (95F).
3. Turn ignition switch OFF and soak the vehicle for 12 hours. CAUTION: Never turn ignition switch ON during soaking.

   NOTE: The vehicle must be cooled with the food open.

4. Start engine and let it idle for 5 minutes or more. CAUTION: Never turn ignition switch OFF during idling.
5. Check 1st trip DTC.

Component Function Check

1.CHECK ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Turn ignition switch OFF.
2. Disconnect ECT sensor harness connector.
3. Remove ECT sensor. Refer to CO-24, "Removal and Installation".
4. Check resistance between ECT sensor terminals by heating with hot water as shown in the figure.

2.CHECK INTERMITTENT INCIDENT

Check intermittent incident

Diagnosis Procedure

1.CHECK ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Check ECT sensor

2.CHECK INTERMITTENT INCIDENT

Check intermittent incident

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 CO-24, "Removal and Installation".
4. Check resistance between engine coolant temperature sensor terminals as per the following.