Diagnostic Procedure

CHECK FUEL TANK TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect fuel level sensor unit harness connector.
3. Turn ignition switch ON.
  
  Fig 1: Disconnecting Fuel Level Sensor Unit Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between fuel level sensor unit terminal 1 and ground with CONSULT-II or tester.
  1. Voltage: Approximately 5V
OK or NG
1. OK: GO TO 3.
2. NG: GO TO 2.
Fig 2: Checking Voltage Between Fuel Level Sensor Unit Terminal 1 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors B103, M91
- Harness connectors M81, F36
- Harness for open or short between ECM and fuel tank temperature sensor
  1. Repair harness or connector.
CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between fuel level sensor unit terminal 4 and body ground. Refer to Wiring Diagram.
  1. Continuity should exist.
3. Also check harness for short to power.
OK or NG
1. OK: GO TO 5.
2. NG: GO TO 4.
DETECT MALFUNCTIONING PART
Check harness for open between fuel tank temperature sensor and body ground.
1. Repair open circuit or short to power in harness or connectors.
CHECK FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance fuel level sensor unit terminals 1 and 4 by heating with hot water as shown in the figure.
Fig 3: Resistance Specification Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 4: Checking Resistance
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
1. OK: GO TO 6.
2. NG: Replace fuel tank temperature sensor.
CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. INSPECTION END.