Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
  Refer to "GROUND INSPECTION ".
  
  Fig 1: Locating Three Ground Screws On Body
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace ground connections.
CHECK FPCM POWER SUPPLY CIRCUIT
1. Disconnect fuel pump control module (FPCM) harness connector.
  
  Fig 2: Locating Fuel Pump Control Module (FPCM) Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch ON.
3. Check voltage between FPCM terminal 2 and ground with CONSULT-II or tester.
  1. Voltage: Battery voltage
OK or NG
1. OK: GO TO 4.
2. NG: GO TO 3.
Fig 3: Checking Voltage Between FPCM Terminal 2 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M141, B211
- Harness for open or short between FPCM and harness connector B211
  1. Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FPCM GROUND CIRCUIT-I FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between FPCM terminal 3 and 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: Repair open circuit or short to power in harness or connectors.
CHECK FPCM GROUND CIRCUIT-II FOR OPEN AND SHORT
1. Disconnect "fuel level sensor unit and fuel pump" harness connector.
2. Disconnect dropping resistor harness connector.
3. Check harness continuity between the following; "fuel level sensor unit and fuel pump" terminal 1 and dropping resistor terminal 2,
  FPCM terminal 4 and dropping resister terminal 2.
  
  Refer to WIRING DIAGRAM .
  1. Continuity should exist.
  Fig 4: Locating Fuel Level Sensor Unit And Fuel Pump Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check harness continuity between the following;
  FPCM terminal 4 and ground, "fuel level sensor and fuel pump" terminal 1 and ground.
  
  Refer to WIRING DIAGRAM .
  1. Continuity should not exist.
5. Also check harness for short to power.
OK or NG
1. OK: GO TO 7.
2. NG: GO TO 6.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors B63, B263
- Harness for open or short between "fuel level sensor unit and fuel pump" and dropping resistor
- Harness for open or short between FPCM and dropping resistor
- Harness for open or short between "fuel level sensor unit and fuel pump" and ground
- Harness for open or short between FPCM and ground
  1. Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FPCM INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 38 and FPCM terminal 4.
  Refer to WIRING DIAGRAM .
  1. Continuity should exist.
3. Check harness continuity between ECM terminal 38 and ground.
  Refer to WIRING DIAGRAM .
  1. Continuity should not exist.
4. Also check harness for short to power.
OK or NG
1. OK: GO TO 9.
2. NG: GO TO 8.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors F105, M135
- Harness connectors M141, B211
- Harness for open or short between ECM and FPCM
  1. Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FPCM OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 39 and FPCM terminal 1.
  Refer to WIRING DIAGRAM .
  1. Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 11.
2. NG: GO TO 10.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors F105, M135
- Harness connectors M141, B211
- Harness for open or short between ECM and FPCM
  1. Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FPCM
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK: GO TO 12.
2. NG: Replace FPCM.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END