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Home >> Nissan-Datsun >> 2005 >> Altima Base >> Repair and Diagnosis >> Engine Performance >> Engine Control System - Qr25DE >> Fuel Pump Circuit >> Diagnostic Procedure

Diagnostic Procedure

  1. CHECK OVERALL FUNCTION 
    1. Turn ignition switch ON.
    2. Pinch fuel feed hose with two fingers.

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

      OK or NG

      • OK: INSPECTION END 
      • NG: GO TO 2.
      Fig 1: Pinching Fuel Feed Hose
      G02527052Courtesy of NISSAN MOTOR CO., U.S.A.
  2. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Turn ignition switch ON.
      Fig 2: Disconnecting ECM Harness Connector
      G02527053Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ECM terminal 114 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

      Fig 3: Checking Voltage Between ECM Terminal 114 And Ground
      G02527054Courtesy of NISSAN MOTOR CO., U.S.A.

      OK or NG

      • OK: GO TO  5.
      • NG: GO TO 3.
  3. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II 
    1. Turn ignition switch OFF.
    2. Disconnect IPDM E/R harness connector E124.
    3. Turn ignition switch ON.
    4. Check voltage between IPDM E/R terminal 40 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

      OK or NG

      • OK: GO TO 4.
      • NG: GO TO  13.
      Fig 4: Checking Voltage Between IPDM E/R Terminal 40 And Ground
      G02527055Courtesy of NISSAN MOTOR CO., U.S.A.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness or connectors E19, F33
    • Harness for open or short between IPDM E/R and ECM

    : Repair harness or connectors.

  5. CHECK CONDENSER POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Disconnect condenser harness connector.
    4. Turn ignition switch ON.
      Fig 5: Disconnecting Condenser Harness Connector
      G02527056Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Check voltage between condenser terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage should exist for 1 second after ignition switch is turned ON. 

      OK or NG

      • OK: GO TO  9.
      • NG: GO TO 6.
      Fig 6: Checking Voltage Between Condenser Terminal 1 And Ground
      G02527057Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK 15A FUSE 
    1. Turn ignition switch OFF.
    2. Disconnect 15A fuse.
    3. Check 15A fuse.

      OK or NG

      • OK: GO TO 7.
      • NG: Replace fuse.
  7. CHECK CONDENSER POWER SUPPLY CIRCUIT-II 
    1. Disconnect IPDM E/R harness connector E124.
    2. Check harness continuity between IPDM E/R terminal 39 and condenser terminal 1.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

      OK or NG

      • OK: GO TO  13.
      • NG: GO TO 8.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness or connectors E33, B3
    • Harness for open or short between IPDM E/R and condenser

      : Repair harness or connectors.

  9. CHECK CONDENSER GROUND CIRCUIT 
    1. Check harness continuity between condenser terminal 2 and ground.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    2. Also check harness for short to power.

      OK or NG

      • OK: GO TO 10.
      • NG: Repair or replace harness or connectors.
  10. CHECK CONDENSER 

    Refer to "COMPONENT INSPECTION ".

    OK or NG

    • OK: GO TO 11.
    • NG: Replace condenser.
  11. 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.
    3. Check harness continuity between "fuel level sensor unit and fuel pump" terminal 1 and harness connector B3 terminal 4, "fuel level sensor unit and fuel pump" terminal 3 and ground.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

      Fig 7: Identifying Fuel Sensor Unit And Fuel Pump Harness Connector
      G02527058Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Also check harness for short to ground and short to power.

      OK or NG

      • OK: GO TO 12.
      • NG: Repair or replace harness or connectors.
  12. CHECK FUEL PUMP 

    Refer to "COMPONENT INSPECTION ".

    OK or NG

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

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG

    • OK: Replace IPDM E/R.
    • NG: Repair or replace harness or connectors.