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Home >> Infiniti >> 2004 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> Fuel Pump >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK OVERALL FUNCTION 
    1. Turn ignition switch ON.
    2. Pinch fuel feed hose with two fingers.
      Fig 1: Pinching Fuel Feed Hose
      G00787515Courtesy of NISSAN MOTOR CO., U.S.A.

    Fuel pressure pulsation should be felt on the fuel feed hose for 1 second after ignition switch is turned ON. 

    OK or NG 

    1. OK: INSPECTION END
    2. NG: GO TO 2
  2. CHECK FUEL PUMP RELAY POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect fuel pump relay.
      Fig 2: Locating Fuel Pump Relay
      G00787516Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Turn ignition switch ON.
    4. Check voltage between fuel pump relay terminals 1, 5 and ground with CONSULT-II or tester.
      Fig 3: Checking Voltage Between Fuel Pump Relay Terminals And Ground
      G00787517Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO  4 .
    2. NG: GO TO 3.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector B5
    • 10A fuse
    • 15A fuse
    • Harness for open or short between fuse and fuel pump relay
    1. Repair harness or connectors
  4. CHECK CONDENSER CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect condenser harness connector.
    3. Check harness continuity between fuel pump relay terminal 3 and condenser terminal 1, condenser terminal 2 and body ground.

      Refer to Wiring Diagram.

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  6 .
    2. NG: GO TO 5.
  5. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness for open or short between fuel pump relay and condenser
    • Harness for open or short between condenser and body ground
    1. Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK CONDENSER 
    1. Turn ignition switch OFF.
    2. Disconnect condenser harness connector.
    3. Check resistance between condenser terminals 1 and 2.
      Fig 4: Checking Resistance Between Condenser Terminals
      G00787518Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 7.
    2. NG: Replace condenser.
  7. CHECK FUEL PUMP POWER SUPPLY AND GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect fuel level sensor unit and fuel pump harness connector.
      Fig 5: Disconnecting Fuel Level Sensor Unit And Fuel Pump Harness Connector
      G00787519Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check harness continuity between fuel pump terminal 3 and body ground, fuel pump terminal 1 and fuel pump relay terminal 3. Refer to Wiring Diagram.

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  9 .
    2. NG: GO TO 8.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness for open or short between fuel pump relay and fuel pump
    • Harness for open or short between fuel pump and body ground
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  9. CHECK FUEL PUMP RELAY OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 23 and fuel pump relay terminal 2. Refer to Wiring Diagram.

      Continuity should exist. 

    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  11 .
    2. NG: GO TO 10.
  10. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors B3, M6
    • Harness connectors M81, F49
    • Harness for open or short between ECM and fuel pump relay
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  11. CHECK FUEL PUMP RELAY 

    With CONSULT-II 

    1. Reconnect fuel pump relay, fuel level sensor unit and fuel pump harness connector and ECM harness connector.
    2. Turn ignition switch ON.
    3. Turn fuel pump relay ON and OFF in ACTIVE TEST mode with CONSULT-II and check operating sound.
      Fig 6: Displaying CONSULT-II ACTIVE TEST Screen
      G00787520Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Without CONSULT-II

      Check continuity between terminals 3 and 5 under the following conditions.

      Fig 7: Checking Continuity Between Terminals
      G00787521Courtesy of NISSAN MOTOR CO., U.S.A.

      OK or NG 

    1. OK: GO TO 12.
    2. NG: Replace fuel pump relay.
  12. CHECK FUEL PUMP 
    1. Disconnect fuel level sensor unit and fuel pump harness connector.
    2. Check resistance between fuel level sensor unit and fuel pump terminals 1 and 3.
      Fig 8: Checking Resistance Between Fuel Level Sensor Unit And Fuel Pump Terminals
      G00787522Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 13.
    2. NG: Replace fuel pump.
  13. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  .

    1. : INSPECTION END
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