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Home › Infiniti › 2010 › M45 Base › Repair and Diagnosis › Engine Performance › System › Engine Control System - DTCS U0101 To P0159 › DTC P0137, P0157 Ho2S2 › Diagnosis Procedure

Diagnosis Procedure

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

      Refer to "GROUND INSPECTION ".

    Fig 1: Identifying Body Ground (M70 And M16)
    G06303084Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace ground connections.

  2. 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.

      Is the 1st trip DTC P0171 or P0174 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, and restart and run engine for at least 5 seconds at idle speed.
    4. Stop engine and reconnect mass air flow sensor harness connector.
    5. Check that DTC P0102 is displayed.
    6. Erase DTC.
    7. Check that DTC P0000 is displayed.
    8. Run engine for at least 10 minutes at idle speed.

      Is the 1st trip DTC P0171 or P0174 detected? 

      Is it difficult to start engine? 

    Fig 2: Identifying Mass Air Flow (MAF) Sensor
    G05210488Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    Yes: Perform trouble diagnosis for DTC P0171 or P0174.

    Refer to "DIAGNOSIS PROCEDURE ".

    No: GO TO 3.

  3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.
      Fig 3: Identifying Heated Oxygen Sensor 2 (HO2S2) Harness Connector
      G06303086Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Disconnect ECM harness connector.
    4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4.

      Refer to SYSTEM WIRING DIAGRAMS article.

      Continuity should exist  .

    5. Also check harness for short to ground and 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 HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Check harness continuity between ECM terminal and HO2S2 terminal as per the following.

      Refer to SYSTEM WIRING DIAGRAMS article.

      DTC REFERENCE CHART

      DTC Terminals Bank
      ECM Sensor
      P0137 55 1 1
      P0157 74 1 2

      Continuity should exist  .

    2. Check harness continuity between the following terminals and ground.

      Refer to SYSTEM WIRING DIAGRAMS article.

      DTC REFERENCE CHART

      DTC Terminals Bank
      ECM Sensor
      P0137 55 1 1
      P0157 74 1 2

      Continuity should not exist  .

    3. Also check harness for short to power.

    OK or NG 

    OK: GO TO 5.

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

  5. CHECK HEATED OXYGEN SENSOR 2

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 6.

    NG: Replace malfunctioning heated oxygen sensor 2.

  6. CHECK INTERMITTENT INCIDENT

    Refer to "DIAGNOSIS PROCEDURE ".

    INSPECTION END 

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