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Home >> Infiniti >> 2012 >> EX35 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P1217 Through P2A03 >> DTC P2A00, P2A03: A/F Sensor 1 >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK GROUND CONNECTION
    1. Turn ignition switch OFF.
    2. Check ground connection M95. Refer to Ground Inspection in "CIRCUIT INSPECTION ".

      Is the inspection result normal? 

      YES: GO TO 2.

      NO: Repair or replace ground connection.

  2. RETIGHTEN A/F SENSOR 1 AND HEATED OXYGEN SENSOR 2

    Loosen and retighten the A/F sensor 1 and heated oxygen sensor 2. Refer to "REMOVAL AND INSTALLATION ".

    : 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 malfunctioning part.

      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.

      Is intake air leak detected? 

      YES: Repair or replace malfunctioning part.

      NO: GO TO 5.

  5. CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
    1. Clear the mixture ratio self-learning value. Refer to "MIXTURE RATIO SELF-LEARNING VALUE CLEAR: SPECIAL REPAIR REQUIREMENT ".
    2. 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? 

      YES: Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to "DIAGNOSIS PROCEDURE " or "DIAGNOSIS PROCEDURE ".

      NO: GO TO 6.

  6. CHECK HARNESS CONNECTOR
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector.
    3. Check harness connector for water.

      Water should not exit. 

      Is the inspection result normal? 

      YES: GO TO 7.

      NO: Repair or replace harness connector.

  7. CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
    1. Turn ignition switch ON.
    2. Check the voltage between A/F sensor 1 harness connector and ground.
      DTC A/F sensor 1 Ground Voltage
      Bank Connector Terminal
      P2A00 1 F3 4 Ground Battery voltage
      P2A03 2 F20 4

      Is the inspection result normal? 

      YES: GO TO  9.

      NO: GO TO 8.

  8. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E3, F1
    • IPDM E/R harness connector E7
    • 15 A fuse (No. 46)
    • 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 FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
      DTC A/F sensor 1 ECM Continuity
      Bank Connector Terminal Connector Terminal
      P2A00 1 F3 1 F102 57 Existed
      2 61
      P2A03 2 F20 1 65
      2 66
    4. Check the continuity between A/F sensor 1 harness connector or ECM harness connector and ground.
      DTC A/F sensor 1 Ground Continuity
      Bank Connector Terminal
      P2A00 1 F3 1 Ground Not existed
      2
      P2A03 2 F20 1
      2
      DTC ECM Ground Continuity
      Connector Terminal
      P2A00 F102 57 Ground Not existed
      61
      P2A03 65
      66
    5. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 10.

      NO: 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 ".

    Is the inspection result normal? 

    YES: GO TO 11.

    NO: GO TO  13.

  11. CHECK HEATED OXYGEN SENSOR 2

    Refer to "COMPONENT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 12.

    NO: Replace malfunctioning heated oxygen sensor 2.

  12. CHECK INTERMITTENT INCIDENT

    Perform "INTERMITTENT INCIDENT ".

    Is the inspection result normal? 

    YES: GO TO 13.

    NO: Repair or replace malfunctioning part.

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

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

    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 Oxygen Sensor Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial service tool).

    Will CONSULT be used? 

    YES: GO TO 14.

    NO: GO TO  15.

  14. CONFIRM A/F ADJUSTMENT DATA

    With CONSULT 

    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 "0.000" is displayed on CONSULT screen.

      Is "0.000" displayed? 

      YES: INSPECTION END

      NO: GO TO 15.

  15. CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE

    Clear the mixture ratio self-learning value. Refer to "MIXTURE RATIO SELF-LEARNING VALUE CLEAR: SPECIAL REPAIR REQUIREMENT ".

    Will CONSULT be used? 

    YES: GO TO 16.

    NO: INSPECTION END

  16. CONFIRM A/F ADJUSTMENT DATA

    With CONSULT 

    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 "0.000" is displayed on CONSULT screen.

      : INSPECTION END

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