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Home >> Nissan-Datsun >> 2014 >> Versa Note S, Automatic CVT Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes & Symptom Tests) >> DTC/Circuit Diagnosis >> DTC P0171: Fuel Injection System Function >> Diagnosis Procedure
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Diagnosis 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
    G04900287Courtesy of NISSAN NORTH AMERICA, INC.

    Is exhaust gas leak detected? 

    YES: Repair or replace.

    NO: GO TO 2.

  2. CHECK FOR INTAKE AIR LEAK AND PCV HOSE 
    1. Listen for an intake air leak after the mass air flow sensor.
    2. Check PCV hose connection.

      Intake air leak detected? 

      YES: Repair or replace.

      NO: GO TO 3.

  3. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect corresponding A/F sensor 1 harness connector.
    3. Disconnect ECM harness connector.
    4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
      A/F sensor 1 ECM Continuity
      Connector Terminal Connector Terminal
      F12 1 F11 49 Existed
      2 53
    5. Check the continuity between A/F sensor 1 harness connector or ECM harness connector and ground.
      A/F sensor 1 Ground Continuity
      Connector Terminal
      F12 1 Ground Not existed
      2
      ECM Ground Continuity
      Connector Terminal
      F11 49 Ground Not existed
      53
    6. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: 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 "WORK PROCEDURE ".
    2. Install fuel pressure gauge and check fuel pressure. Refer to "WORK PROCEDURE ".

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

      Is the inspection result normal? 

      YES: GO TO  6.

      NO: GO TO 5.

  5. CHECK FUEL HOSES AND FUEL TUBES 

    Check fuel hoses and fuel tubes for clogging.

    Is the inspection result normal? 

    YES: Replace "fuel filter and fuel pump assembly". Refer to "EXPLODED VIEW ".

    NO: Repair or replace

  6. CHECK MASS AIR FLOW SENSOR 

    With CONSULT 

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

      0.8 - 4.0 g/s: at idling 

      2.0 - 10.0 g/s: at 2, 500 rpm 

    With GST 

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

      0.8 - 4.0 g/s: at idling 

      2.0 - 10.0 g/s: at 2, 500 rpm 

      Is the measurement value within the specification? 

      YES: GO TO 7.

      NO: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to "DTC LOGIC ".

  7. 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.

    Without CONSULT 

    1. Let engine idle.
    2. Listen to each fuel injector operating sound.

      Clicking noise should be heard. 

      Is the inspection result normal? 

      YES: GO TO 8.

      NO: Perform trouble diagnosis for FUEL INJECTOR. Refer to "COMPONENT FUNCTION CHECK ".

      Fig 2: Checking Fuel Injector Operating Sound
      G04875112Courtesy of NISSAN NORTH AMERICA, INC.
  8. CHECK FUEL INJECTOR 
    1. Turn ignition switch OFF.
    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. Remove fuel tube assembly. Refer to "REMOVAL AND INSTALLATION ".

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

    5. Disconnect all ignition coil harness connectors.
    6. Prepare pans or saucers under each fuel injector.
    7. Crank engine for about 3 seconds.

      Fuel should be sprayed evenly for each fuel injector. 

      Is the inspection result normal? 

      YES: GO TO 9.

      NO: Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones. Refer to "REMOVAL AND INSTALLATION ".

      Fig 3: Checking Fuel Injector Spray
      G04886853Courtesy of NISSAN NORTH AMERICA, INC.
  9. CHECK INTERMITTENT INCIDENT 

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END