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Home >> Infiniti >> 2012 >> M37 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0137 Through P0456 >> P0137, P0157: Ho2S2 >> 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. 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 P0171 or P0174 detected? Is it difficult to start engine? 

      YES: Perform trouble diagnosis for DTC P0171 or P0174. Refer to "DTC LOGIC ".

      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.
    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
      P0137 1 F54 1 F102 84 Existed
      P0157 2 F53 1
    5. 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
      P0137 1 F54 4 F102 76 Existed
      P0157 2 F53 4 80
    2. Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.
      DTC HO2S2 Ground Continuity
      Bank Connector Terminal
      P0137 1 F54 4 Ground Not existed
      P0157 2 F53 4
      DTC ECM Ground Continuity
      Bank Connector Terminal
      P0137 1 F102 76 Ground Not existed
      P0157 2 80
    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 ".

    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.

    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 heated 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

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