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Home › Nissan-Datsun › 2008 › Sentra Base, Standard › Repair and Diagnosis › Engine Performance › Engine Control Systems › Engine Control System - DTCS P0506 To P2A00 (MR20DE) › DTC P2A00 A/F Sensor 1 › Diagnostic Procedure

Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten ground screws on the body.

      Refer to "GROUND INSPECTION ".

      • Body ground (1)

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

    Fig 1: Identifying Body Ground
    G04925191Courtesy of NISSAN MOTOR CO., U.S.A.
  2. RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1 

    Loosen and retighten the air fuel ratio (A/F) sensor 1 (2).

    • Air fuel ratio (A/F) sensor harness connector (1)

      Tightening torque: 50 N.m (5.1 kg-m, 37 ft-lb) 

    : GO TO 3.

    Fig 2: Identifying Air Fuel Ratio (A/F) Sensor Harness Connector
    G04925206Courtesy of NISSAN MOTOR CO., U.S.A.
  3. 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 4.

    NG: Repair or replace.

  4. CLEAR THE SELF-LEARNING DATA. 

    With CONSULT-III 

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

      Is the 1st trip DTC P0171 and P0172 detected? 

      Is it difficult to start engine? 

    Without CONSULT-III 

    1. Start engine and warm it up to normal operating temperature.
    2. Turn ignition switch OFF.
    3. Disconnect mass air flow sensor (1) 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 "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION ".
    8. Make sure DTC P0000 is displayed.
    9. Run engine for at least 10 minutes at idle speed.

      Is the 1st trip DTC P0171 and P0172 detected? 

      Is it difficult to start engine? 

      Fig 3: Identifying Mass Air Flow Sensor
      G04925227Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

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

    No: GO TO 5.

  5. CHECK HARNESS CONNECTOR 
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector (1).
      • Air fuel ratio (A/F) sensor (2)
    3. Check harness connector for water.

      Water should no exist. 

    OK or NG 

    OK: GO TO 6.

    NG: Repair or replace harness connector.

    Fig 4: Identifying A/F Sensor 1 Harness Connector And Air Fuel Ratio (A/F) Sensor
    G04925206Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK AIR FUEL RATIO (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-III or tester.

      Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  8.

    NG: GO TO 7.

    Fig 5: Checking Voltage Between A/F Sensor 1 Terminal 4 And Ground
    G04874929Courtesy of NISSAN MOTOR CO., U.S.A.
  7. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E3, F2
    • 10A fuse
    • Harness for open or short between A/F sensor 1 and fuse

    : Repair or replace harness or connectors.

  8. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
      ECM TERMINAL CHART

      A/F sensor 1 terminal ECM terminal
      1 49
      2 53

      Continuity should exist. 

    4. Check harness continuity between ECM terminals 49, 53 or A/F sensor 1 terminals 1, 2 and ground.

      Refer to WIRING DIAGRAM .

      Continuity should not exist. 

    5. Also check harness for short to power.

    OK or NG 

    OK: GO TO 9.

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

  9. CHECK A/F SENSOR 1 HEATER 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 10.

    NG: GO TO  11.

  10. CHECK INTERMITTENT INCIDENT 

    Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG 

    OK: GO TO 11.

    NG: Repair or replace.

  11. REPLACE AIR FUEL RATIO (A/F) SENSOR 1 

    Replace air fuel ratio (A/F) sensor 1.

    CAUTION:
    • Discard any air fuel ratio (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 air fuel ratio (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 12.

  12. CONFIRM A/F ADJUSTMENT DATA 
    1. Turn ignition switch ON.
    2. Select "A/F ADJ-B1" in "DATA MONITOR" mode with CONSULT-III.
    3. Make sure that "0.000" is displayed on CONSULT-III screen.

    OK or NG 

    OK: INSPECTION END 

    NG: GO TO 13.

  13. CLEAR THE SELF-LEARNING DATA 

    With CONSULT-III 

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

    Without CONSULT-III 

    1. Start engine and warm it up to normal operating temperature.
    2. Turn ignition switch OFF.
    3. Disconnect mass air flow sensor harness (1) 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 "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION ".
    8. Make sure DTC P0000 is displayed.

    : GO TO 14.

    Fig 6: Identifying Mass Air Flow Sensor Harness
    G04925227Courtesy of NISSAN MOTOR CO., U.S.A.
  14. CONFIRM A/F ADJUSTMENT DATA 
    1. Turn ignition switch OFF and then ON.
    2. Select "A/F ADJ-B1" in "DATA MONITOR" mode with CONSULT-III.
    3. Make sure that "0.000" is displayed on CONSULT-III screen.

    : INSPECTION END 

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