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Home >> Nissan-Datsun >> 2004 >> Sentra Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - QG18DE >> 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 fingers.

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

    OK or NG 

    1. OK : INSPECTION END 
    2. NG : GO TO 2.
    Fig 1: Pinching Fuel Feed Hose
    G00773416Courtesy of NISSAN MOTOR CO., U.S.A.
  2. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch OFF.
    2. Disconnect fuel pump relay.
    3. Turn ignition switch ON.
      Fig 2: Disconnecting Fuel Pump Relay
      G00773417Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between fuel pump relay terminals 1, 5 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 
      Fig 3: Checking Voltage Between Fuel Pump Relay Terminals 1, 5 And Ground
      G00773418Courtesy 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.

    • 10A fuse
    • 15A fuse
    • Fuse block (J/B) connector B4
    • Harness for open or short between fuse and fuel pump relay
      1. : Repair harness or connectors.
  4. CHECK POWER GROUND CIRCUIT AND GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect "fuel level sensor unit and fuel pump" harness connector.
    3. Check harness continuity between "fuel level sensor unit and fuel pump" terminal 3 and body ground, "fuel level sensor unit and fuel pump" terminal 1 and fuel pump relay terminal 3. Refer to WIRING DIAGRAM .
      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.
      Fig 4: Disconnecting Fuel Level Sensor Unit And Fuel Pump Harness Connector
      G00773419Courtesy of NISSAN MOTOR CO., U.S.A.

    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 and "fuel level sensor unit and fuel pump" and body ground
    • Harness for open or short between and "fuel level sensor unit and fuel pump" and fuel pump relay
      1. : Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK FUEL PUMP RELAY OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 113 and fuel pump relay connector terminal 2.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK : GO TO  8.
    2. NG : GO TO 7.
  7. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors B3, M16
    • Harness connector M58, F26
    • 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.
  8. CHECK FUEL PUMP RELAY 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 9.
    2. NG : Replace fuel pump relay.
  9. CHECK FUEL PUMP 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK : GO TO 10.
    2. NG : Replace "fuel level sensor unit and fuel pump".
  10. CHECK INTERMITTENT INCIDENT 

    Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. INSPECTION END 

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