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Home >> Nissan-Datsun >> 2004 >> Altima S, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1183 (Engine Control System - DTCS U0101 To P0183 (VQ40DE)) >> DTC P0172, P0175: Fuel Injection System Function >> Diagnosis Procedure

Diagnosis Procedure

WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
  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
    G08170520Courtesy of NISSAN NORTH AMERICA, INC.

    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: Identifying A/F Sensor 1 Harness Connector
      G08170521Courtesy of NISSAN NORTH AMERICA, INC.
    3. Disconnect ECM harness connector.
    4. Check harness continuity between A/F sensor 1 terminal and ECM terminal as follows. Refer to WIRING DIAGRAM .
      Bank 1 A/F sensor 1 terminal ECM terminal
      1 35
      2 56
      Bank 2 1 16
      2 75

      Continuity should exist  .

    5. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM .
      Bank 1 Bank 2
      A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal
      1 35 1 16
      2 56 2 75

      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 CHECK ".
    2. Install fuel pressure gauge and check fuel pressure. Refer to "FUEL PRESSURE CHECK ".

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

    OK or NG 

    OK (With CONSULT)>>GO TO  6.

    OK (Without CONSULT)>>GO TO  7.

    NG: GO TO 5.

  5. DETECT MALFUNCTIONING PART

    Check the following.

    Repair or replace.

  6. CHECK MASS AIR FLOW SENSOR

    With CONSULT 

    1. Install all removed parts.
    2. Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT.

    2.0 - 6.0 g/s: at idling 

    7.0 - 20.0 g/s: at 2, 500 RPM 

    OK or NG 

    OK: GO TO  8.

    NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "COMPONENT DESCRIPTION ".

  7. CHECK MASS AIR FLOW SENSOR

    With GST 

    1. Install all removed parts.
    2. Check mass air flow sensor signal in Service $01 with GST.

    2.0 - 6.0 g/s: at idling 

    7.0 - 20.0 g/s: at 2, 500 RPM 

    OK or NG 

    OK (P0172)>>GO TO  9.

    OK (P0175)>>GO TO  11.

    NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "COMPONENT DESCRIPTION ".

  8. CHECK FUNCTION OF FUEL INJECTOR

    With CONSULT 

    1. Start engine.
    2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
    3. Make sure that each circuit produces a momentary engine speed drop.

    OK or NG 

    OK: GO TO  12.

    NG: Perform trouble diagnosis for FUEL INJECTOR, refer to "COMPONENT DESCRIPTION ".

  9. CHECK FUNCTION OF FUEL INJECTOR-I

    Without CONSULT 

    1. Stop engine.
    2. Disconnect harness connector F44 (3), F201 (1)
      Fig 3: Identifying Vacuum Tank And Harness Connectors
      G08170522Courtesy of NISSAN NORTH AMERICA, INC.
    3. Turn ignition switch ON.
    4. Check voltage between harness connector F44 terminal 3 and ground with CONSULT or tester.

      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 .

      Cylinder Harness connector F44 terminal ECM terminal
      1 2 23
      3 1 22
      5 4 21

      Continuity should exist  .

      Fig 4: Checking Voltage Between Harness Connector F44 Terminal 3 And Ground Using Tester
      G08170523Courtesy of NISSAN NORTH AMERICA, INC.
    8. Also check harness for short to ground and short to power.

    OK or NG 

    OK: GO TO 10.

    NG: Perform trouble diagnosis for FUEL INJECTOR, refer to "COMPONENT DESCRIPTION ".

  10. CHECK FUNCTION OF FUEL INJECTOR-II

    Provide battery voltage between harness connector F201 as follows and then interrupt it. Listen to each fuel injector operating sound.

    Cylinder Harness connector F201 terminal
    (+) (-)
    1 3 2
    3 3 1
    5 3 4

    Operating sound should exist  .

    Fig 5: Applying Battery Voltage Between Harness Connector F101 Terminals
    G08170524Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO  12.

    NG: Perform trouble diagnosis for FUEL INJECTOR, refer to "COMPONENT DESCRIPTION ".

  11. CHECK FUNCTION OF FUEL INJECTOR
    1. Start engine.
    2. Listen to fuel injectors No. 2, No. 4, No. 6 operating sound.

    Clicking noise should exist  .

    Fig 6: Checking Fuel Injector Operating Sound
    G08170525Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 12.

    NG: Perform trouble diagnosis for FUEL INJECTOR, refer to "COMPONENT DESCRIPTION ".

  12. CHECK FUEL INJECTOR
    1. Remove fuel injector assembly. Refer to "REMOVAL AND INSTALLATION ".

      Keep fuel hose and all fuel injectors connected to fuel tube.

    2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
    3. Disconnect all fuel injector harness connectors.
    4. Disconnect all ignition coil harness connectors.
    5. Prepare pans or saucers under each fuel injector.
    6. Crank engine for about 3 seconds.

    Make that sure fuel does not drip from fuel injector.

    OK or NG 

    OK (Does not drip.)>>GO TO 13.

    NG (Drips.)>>Replace the fuel injectors from which fuel is dripping. Refer to "REMOVAL AND INSTALLATION ". Always replace O-ring with new one.

  13. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    >> INSPECTION END 

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