Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten four ground screws on the body.
  Refer to "GROUND INSPECTION ."
  
  Fig 1: Checking Ground Connections
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG

OK: GO TO 2.

NG: Repair or replace ground connections.
CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor harness connector (1).
  - Vehicle front
  - Fuse and fusible link box (2)
2. Turn ignition switch ON.
  
  Fig 2: Identifying Engine Coolant Temperature Sensor Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check voltage between ECT sensor terminal 1 and ground with CONSULT-III or tester.
  Voltage: Approximately 5V
Fig 3: Checking Voltage Between ECT Sensor Terminal 1 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: GO TO 3.

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 connectors.
3. Check harness continuity between ECT sensor terminal 2 and ECM terminal 67.
  Refer to Wiring Diagram.
  
  Continuity should exist .
4. Also check harness for short to ground and short to power.
OK or NG

OK: GO TO 4.

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

OK: GO TO 5.

NG: Replace engine coolant temperature sensor.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ."

>>INSPECTION END