Diagnostic Procedure

Check Ground Connections
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. See Figure. Refer to GROUND INSPECTION .
OK or NG
1. OK: Go to 2.
2. NG: Repair or replace ground connections.
Check ECT Sensor Power Supply Circuit
1. Disconnect engine coolant temperature (ECT) sensor harness connector. See Figure.
2. Turn ignition switch ON.
3. Check voltage between ECT sensor terminal 1 and ground with CONSULT-II or tester.
  
  Fig 1: Verifying ECT Sensor Reference Voltage (DVOM)
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Voltage: Approximately 5V
OK or NG
1. OK: Go to 3.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Check ECT Sensor Ground Circuit For Open And Short
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 wiring diagram. See Figure.
  Continuity should exist .
4. Also check harness for short to ground and short to power.
OK or NG
1. OK: Go to 4.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Check Engine Coolant Temperature Sensor
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: Go to 5.
2. NG: Replace engine coolant temperature sensor.
Check Intermittent Incident
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. Inspection end