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Home >> Nissan-Datsun >> 2005 >> Altima SE-R, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control System - VQ35DE >> DTC P0172, P0175: Fuel Injection System Function >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK EXHAUST GAS LEAK 
    1. Start engine and run it at idle.
    2. Listen for an exhaust gas leak before three way catalyst (manifold).
      Fig 1: Checking Exhaust Gas Leak
      G02525758Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO 2.
    • NG: Repair or replace.
  2. CHECK FOR INTAKE AIR LEAK 

    Listen for an intake air leak after the mass air flow sensor.

    OK or NG 

    • OK: GO TO 3.
    • NG: Repair or replace.
  3. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect corresponding A/F sensor 1 harness connector.
      Fig 2: Disconnecting Corresponding A/F Sensor 1 Harness Connector
      G02525759Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Disconnect ECM harness connector.
    4. Check harness continuity between the following terminals.

      Refer to WIRING DIAGRAM .

      Fig 3: Sensor Terminals Reference
      G02525760Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should exist. 

    5. Check harness continuity between the following terminals and ground.

      Refer to WIRING DIAGRAM .

      Fig 4: Sensor Terminals Reference
      G02525761Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should not exist. 

    6. Also check harness for short to power.

    OK or NG 

    • OK: GO TO 4.
    • NG: Repair open circuit or short to ground or short to power in harness or connectors.
  4. CHECK FUEL PRESSURE 
    1. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
    2. Install fuel pressure gauge and check fuel pressure. Refer to "FUEL PRESSURE CHECK ".

      At idling: Approx. 350 kPa (3.57 kg/cm 2  , 51 psi) 

    OK or NG 

    • OK (With CONSULT-II): GO TO  4.
    • OK (Without CONSULT-II): GO TO  5.
    • NG: GO TO 5.
  5. DETECT MALFUNCTIONING PART 

    Check the following.

    OK or NG 

    • OK (P0172): GO TO  7.
    • OK (P0175): GO TO  9.
    • NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DTC P0101 MAF SENSOR .
  6. CHECK FUNCTION OF INJECTOR 

    With CONSULT-II 

    1. Start engine.
    2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-II.
    3. Make sure that each circuit produces a momentary engine speed drop.
      Fig 5: Identifying Consult-II Active Test
      G02525762Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO  10.
    • NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
  7. CHECK FUNCTION OF INJECTOR-I 

    Without CONSULT-II 

    1. Stop engine.
    2. Disconnect harness connector F44, F101
    3. Turn ignition switch ON.
      Fig 6: Disconnecting Harness Connector
      G02525763Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between harness connector F44 terminal 6 (with triple meters) or 5 (without triple meters) and ground with CONSULT-II or tester.
      Fig 7: Checking Voltage Between Harness Connector F44 Terminal 6 Or 5 And Ground
      G02525764Courtesy of NISSAN MOTOR CO., U.S.A.

      Voltage: Battery voltage 

    5. Turn ignition switch OFF.
    6. Disconnect ECM harness connector.
    7. Check harness continuity between harness connector F44 and ECM as follows.

      Refer to WIRING DIAGRAM .

      With triple meters 

      CYLINDER AND CONNECTOR TERMINALS

      Cylinder Harness connector F44 terminal ECM terminal
      1 1 23
      3 3 22
      5 7 21

      Without triple meters 

      CYLINDER AND CONNECTOR TERMINALS

      Cylinder Harness connector F44 terminal ECM terminal
      1 6 23
      3 2 22
      5 1 21

      Continuity should exist. 

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

    OK or NG 

    • OK: GO TO 10.
    • NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
  8. CHECK FUNCTION OF INJECTOR-II 

    Provide battery voltage between harness connector F101 as follows and then interrupt it. Listen to each injector operating sound.

    Fig 8: Checking Function Of Injector-II
    G02525765Courtesy of NISSAN MOTOR CO., U.S.A.

    With triple meters 

    Fig 9: Cylinder And Connector Terminal Reference With Triple Meters
    G02525766Courtesy of NISSAN MOTOR CO., U.S.A.

    Without triple meters 

    Fig 10: Cylinder And Connector Terminal Reference Without Triple Meters
    G02525767Courtesy of NISSAN MOTOR CO., U.S.A.

    Operating sound should exist. 

    OK or NG 

    • OK: GO TO  10.
    • NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
  9. CHECK FUNCTION OF INJECTOR 
    1. Start engine.
    2. Listen to injectors No. 2, No. 4, No. 6 operating sound.

      Clicking noise should exist. 

    OK or NG 

    • OK: GO TO 12.
    • NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
      Fig 11: Checking Function Of Injector
      G02525768Courtesy of NISSAN MOTOR CO., U.S.A.
  10. CHECK INJECTOR 
    1. Remove injector assembly. Refer to " FUEL INJECTOR AND FUEL TUBE ".
    2. Keep fuel hose and all injectors connected to injector gallery.
    3. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
    4. Disconnect all injector harness connectors.
    5. Disconnect all ignition coil harness connectors.
    6. Prepare pans or saucers under each injectors.
    7. Crank engine for about 3 seconds.
    8. Make sure fuel does not drip from injector.

    OK or NG 

    • OK (Does not drip.): GO TO 13.
    • NG (Drips.):Replace the injectors from which fuel is dripping. Always replace O-ring with new one.
  11. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    • : INSPECTION END
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