Diagnosis Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.

Refer to "GROUND INSPECTION ".

Fig 1: Identifying Body Ground (M70 And M16)

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

OK: GO TO 2.

NG: Repair or replace ground connections.

1. Disconnect engine coolant temperature (ECT) sensor harness connector.
   Fig 2: Identifying Engine Coolant Temperature Sensor

   Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch ON.
3. Check voltage between ECT sensor terminal 1 and ground with CONSULT-III or tester.

Voltage: Approximately 5V 

OK or NG 

OK: GO TO  4.

NG: GO TO 3.

Fig 3: Checking Voltage Between ECT Sensor Terminal 1 And Ground

Courtesy of NISSAN MOTOR CO., U.S.A.

Check the following.

• Harness connector F291, F50
• Harness for open or short between ECM and engine coolant temperature sensor

Repair open circuit or short to ground or short to power in harness or connectors.

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECT sensor terminal 2 and ECM terminal 67.

   Refer to SYSTEM WIRING DIAGRAMS article.

   Continuity should exist  .

4. Also check harness for short to ground and short to power.

OK or NG 

OK: GO TO  6.

NG: GO TO 5.

Check the following.

• Harness connector F291, F50
• Harness for open and short between ECT sensor and ECM

Repair open circuit or short to ground or short to power in harness or connectors.

Refer to "COMPONENT INSPECTION ".

OK or NG 

OK: GO TO 7.

NG: Replace engine coolant temperature sensor.

Refer to "DIAGNOSIS PROCEDURE ".

INSPECTION END