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Home >> Nissan-Datsun >> 2004 >> Altima S, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1184 (Engine Control System - DTCS P0643 To P2A03 (VQ40DE)) >> DTC P2A00, P2A03: A/F Sensor 1 >> 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 GROUND CONNECTIONS
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION ".
    Fig 1: Checking Ground Connections
    G08170769Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1 AND HEATED OXYGEN SENSOR 2

    Loosen and retighten the air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2. Refer to "ENGINE CONTROL COMPONENT PARTS LOCATION ".

    GO TO 3.

  3. CHECK FOR EXHAUST GAS LEAK
    1. Start engine and run it at idle.
    2. Listen for an exhaust gas leak before the three way catalyst 2.

    Is exhaust gas detected? 

    YES: Repair or replace.

    NO: GO TO 4.

  4. CHECK FOR INTAKE AIR LEAK
    1. Start engine and run it at idle.
    2. Listen for an intake air leak after the mass air flow sensor.

    OK or NG 

    OK: GO TO 5.

    NG: Repair or replace.

  5. CLEAR THE SELF-LEARNING DATA.

    With CONSULT 

    1. Start engine and warm it up to normal operating temperature.
    2. Select "SELF-LEARNING CONT" in "WORK SUPPORT" mode with CONSULT.
    3. Clear the self-learning control coefficient by touching "CLEAR".
    4. Run engine for at least 10 minutes at idle speed.

    Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? 

    Is it difficult to start engine? 

    Without CONSULT 

    1. Start engine and warm it up to normal operating temperature.
    2. Turn ignition switch OFF.
    3. Disconnect mass air flow sensor harness connector.
    4. Restart engine and let it idle for at least 3 seconds.
    5. Stop engine and reconnect mass air flow sensor harness connector.
    6. Make sure DTC P0102 is displayed.
    7. Erase the DTC memory. Refer to "ON BOARD DIAGNOSIS FUNCTION ".
    8. Make sure DTC P0000 is displayed.
    9. Run engine for at least 10 minutes at idle speed.

    Is the 1st trip DTC P0171, P0172 or P0174, P0175 detected? 

    Is it difficult to start engine? 

    Fig 2: Identifying Mass Air Flow Sensor Harness Connector
    G08170770Courtesy of NISSAN NORTH AMERICA, INC.

    Yes or No 

    Yes: Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to P0171, P0174 FUEL INJECTION SYSTEM FUNCTION or P0172, P0175 FUEL INJECTION SYSTEM FUNCTION .

    No: GO TO 6.

  6. CHECK HARNESS CONNECTOR
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector.
      Fig 3: Identifying A/F Sensor 1 Harness Connector
      G08170771Courtesy of NISSAN NORTH AMERICA, INC.
    3. Check harness connector for water.

    Water should not exit  .

    OK or NG 

    OK: GO TO 7.

    NG: Repair or replace harness connector.

  7. CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
    1. Turn ignition switch ON.
    2. Check voltage between A/F sensor 1 terminal 4 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  9.

    NG: GO TO 8.

    Fig 4: Checking Voltage Between A/F Sensor 1 Harness Connector Terminal 4 And Ground Using Tester
    G08170772Courtesy of NISSAN NORTH AMERICA, INC.
  8. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E2, F32
    • IPDM E/R connector E119
    • 15 A fuse (No. 51)
    • Harness for open or short between A/F sensor 1 and fuse

    Repair or replace harness or connectors.

  9. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between A/F sensor 1 terminal and ECM terminal as follows.

      Refer to WIRING DIAGRAM .

        A/F sensor 1 terminal ECM terminal
      Bank1 1 16
      2 75
      Bank 2 1 35
      2 56

      Continuity should exist  .

    4. 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 16 1 35
      2 75 2 56

      Continuity should not exist  .

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

    OK or NG 

    OK: GO TO 10.

    NG: Repair open circuit or short to ground or short to power in harness or connectors.

  10. CHECK A/F SENSOR 1 HEATER

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  11.

    NG: GO TO  13.

  11. CHECK HEATED OXYGEN SENSOR 2

    Refer to "COMPONENT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 12.

    NO: Replace heated oxygen sensor 2. Refer to "ENGINE CONTROL COMPONENT PARTS LOCATION ".

  12. CHECK INTERMITTENT INCIDENT

    Perform "INTERMITTENT INCIDENT ".

    OK or NG 

    OK: GO TO 13.

    NG: Repair or replace.

  13. REPLACE A/F SENSOR 1

    Replace malfunctioning A/F sensor 1. Refer to "ENGINE CONTROL COMPONENT PARTS LOCATION ".

    CAUTION:
    • Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
    • Before installing new A/F sensor, clean exhaust system threads using Heated Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

    GO TO 14.

  14. CONFIRM A/F ADJUSTMENT DATA
    1. Turn ignition switch ON.
    2. Select "A/F ADJ-B1" and "A/F ADJ-B2" in "DATA MONITOR" mode with CONSULT.
    3. Make sure that "0" is displayed on CONSULT screen.

    OK or NG 

    OK: INSPECTION END 

    NG: GO TO 15.

  15. CREAR A/F ADJUSTMENT DATA

    With CONSULT 

    1. Start engine and warm it up to normal operating temperature.
    2. Select "SELF-LEARNING CONT" in "WORK SUPPORT" mode with CONSULT.
    3. Clear the self-learning control coefficient by touching "CLEAR".

    Without CONSULT 

    1. Start engine and warm it up to normal operating temperature.
    2. Turn ignition switch OFF.
    3. Disconnect mass air flow sensor harness connector.
    4. Restart engine and let it idle for at least 5 seconds.
    5. Stop engine and reconnect mass air flow sensor harness connector.
    6. Make sure DTC P0102 is displayed.
    7. Erase the DTC memory. Refer to "ON BOARD DIAGNOSIS FUNCTION ".
    8. Make sure DTC P0000 is displayed.

    GO TO 16.

    Fig 5: Identifying Mass Air Flow Sensor Harness Connector
    G08170773Courtesy of NISSAN NORTH AMERICA, INC.
  16. CONFIRM A/F ADJUSTMENT DATA
    1. Turn ignition switch OFF and then ON.
    2. Select "A/F ADJ-B1" and "A/F ADJ-B2" in "DATA MONITOR" mode with CONSULT.
    3. Make sure that "0" is displayed on CONSULT screen.

    OK or NG 

    OK: INSPECTION END 

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