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Home >> Infiniti >> 2013 >> M56 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U0101 To P0183 >> DTC P0138, P0158: Ho2S2 >> Diagnosis Procedure

Diagnosis Procedure

  1. INSPECTION START 

    Confirm the detected malfunction (A or B). Refer to "DTC LOGIC ".

    Which malfunction is detected? 

    A: GO TO 2

    B: GO TO  8.

  2. CHECK HEATED OXYGEN SENSOR 2 CONNECTOR 
    1. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.
    2. Check that water is not inside connectors.

      Is the inspection result normal? 

      YES: GO TO 3.

      NO: Repair or replace harness or connectors.

  3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check the continuity between HO2S2 harness connector and ECM harness connector.
      DTC HO2S2 ECM Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 1 F111 100 Existed
      P0158 2 F88 1
    3. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: Repair open circuit, short to ground or short to power in harness or connectors.

  4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check the continuity between HO2S2 harness connector and ECM harness connector.
      DTC HO2S2 ECM Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 4 F111 96 Existed
      P0158 2 F88 4 87
    2. Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.
      DTC HO2S2 ECM Ground Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 4 F111 96 Ground Not existed
      P0158 2 F88 4 87
    3. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 5.

      NO: Repair open circuit, short to ground or short to power in harness or connectors.

  5. CHECK HEATED OXYGEN SENSOR 2 

    Refer to "COMPONENT INSPECTION (HO2 SENSOR 2) ".

    Is the inspection result normal? 

    YES: GO TO  7.

    NO: GO TO 6.

  6. REPLACE HEATED OXYGEN SENSOR 2 

    Replace malfunctioning heated oxygen sensor 2. Refer to "EXPLODED VIEW ".

    CAUTION:
    • Discard any heated oxygen 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 oxygen 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).

    : INSPECTION END

  7. CHECK INTERMITTENT INCIDENT 

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

  8. CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE 
    1. Clear the mixture ratio self-learning value. Refer to "WORK PROCEDURE ".
    2. Run engine for at least 10 minutes at idle speed.

      Is the 1st trip DTC P0172 or P0175 detected? Is it difficult to start engine? 

      YES: Perform trouble diagnosis for DTC P0172, P0175. Refer to "DTC LOGIC ".

      NO: GO TO 9.

  9. CHECK HEATED OXYGEN SENSOR 2 GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.
    3. Disconnect ECM harness connector.
    4. Check the continuity between HO2S2 harness connector and ECM harness connector.
      DTC HO2S2 ECM Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 1 F111 100 Existed
      P0158 2 F88 1
    5. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO 10.

      NO: Repair open circuit, short to ground or short to power in harness or connectors.

  10. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check the continuity between HO2S2 harness connector and ECM harness connector.
      DTC HO2S2 ECM Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 4 F111 96 Existed
      P0158 2 F88 4 87
    2. Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.
      DTC HO2S2 ECM Ground Continuity
      Bank Connector Terminal Connector Terminal
      P0138 1 F87 4 F111 96 Ground Not existed
      P0158 2 F88 4 87
    3. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 11.

      NO: Repair open circuit, short to ground or short to power in harness or connectors.

  11. CHECK HEATED OXYGEN SENSOR 2 

    Refer to "COMPONENT INSPECTION (HO2 SENSOR 2) ".

    Is the inspection result normal? 

    YES: GO TO  13.

    NO: GO TO 12.

  12. REPLACE HEATED OXYGEN SENSOR 2 

    Replace malfunctioning heated oxygen sensor 2. Refer to "EXPLODED VIEW ".

    CAUTION:
    • Discard any heated oxygen 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 oxygen 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).

    : INSPECTION END

  13. CHECK INTERMITTENT INCIDENT 

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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