Diagnostic Procedure

CHECK FUEL LEVEL SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch off.
2. Disconnect fuel level sensor unit and fuel pump harness connector.
3. Turn ignition switch on.
4. Check voltage between fuel level sensor unit and fuel pump terminal 2 and ground with CONSULT-II or a tester.
  
  Fig 1: Checking Fuel Level Sensor Power Supply Circuit
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  OK OR NG
  1. OK: GO TO 3 .
  2. NG: GO TO 2.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M6, B3
- Harness for open or short between combination meter and fuel level sensor unit and fuel pump
1. : Repair or replace harness or connectors.
CHECK FUEL LEVEL SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch off.
2. Check harness continuity between fuel level sensor unit and fuel pump terminal 5 and body ground. Refer to wiring diagram.
  Continuity should exist.
1. Also check harness for short to power.
OK OR NG
1. OK: GO TO 4.
2. NG: repair open circuit or short to power in harness or connectors.
CHECK FUEL LEVEL SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 69 and fuel level sensor unit and fuel pump terminal 2, ECM terminal 78 and fuel level sensor unit and fuel pump terminal 5. Refer to wiring diagram.
  Continuity should exist.
1. Also check harness for short to ground and short to power.
OK OR NG
1. OK: GO TO 6 .
2. NG: GO TO 5.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M229, F66
- Harness connectors M6, B3
- Harness for open or short between ECM and fuel level sensor unit and fuel pump
1. : Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FUEL LEVEL SENSOR
Refer to FUEL LEVEL SENSOR UNIT CHECK .

OK OR NG
1. OK: GO TO 7.
2. NG: Replace fuel level sensor unit and fuel pump.
CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. : INSPECTION END