Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
  Refer to "GROUND INSPECTION ".
  
  Fig 1: Identifying Body 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 (1) harness connector.
  - <= : Vehicle front
2. Turn ignition switch ON.
  
  Fig 2: Identifying Engine Coolant Temperature Sensor Harness 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
OK or NG

OK: GO TO 3.

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

Fig 3: Checking Voltage Between ECT Sensor Terminal 1 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 52 and ECT sensor terminal 2.
  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