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Home >> Nissan-Datsun >> 2008 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0137 To P0445 (Qr25DE) >> DTC P0137, P0157 Ho2S2 >> Diagnostic Procedure
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Diagnostic Procedure

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

      Refer to "GROUND INSPECTION ".

      Fig 1: Identifying Body Ground Connections
      G04925915Courtesy 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, 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.
      • <==: Vehicle front
    4. Stop engine and reconnect mass air flow sensor harness connector.
    5. Make sure DTC P0102 is displayed.
    6. Erase the DTC memory. Refer to "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION ".
    7. Make sure DTC P0000 is displayed.
    8. Run engine for at least 10 minutes at idle speed.

      Is the 1st trip DTC P0171, P0174 detected? 

      Is it difficult to start engine? 

      Fig 2: Identifying Mass Air Flow Sensor Harness Connector
      G04925826Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    Yes: Perform trouble diagnosis for DTC P0171, P0174. Refer to "DTC P0171 FUEL INJECTION SYSTEM FUNCTION ".

    No: GO TO 3.

  3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect heated oxygen sensor 2 harness connector.
      • Heated oxygen sensor 2 (Bank 1) harness connector (1)
      • Heated oxygen sensor 2 (Bank 1) (2)
      • Heated oxygen sensor 2 (Bank 2) (3)
      • Heated oxygen sensor 2 (Bank 2) harness connector (4)
    3. Disconnect ECM harness connector.
    4. Check harness continuity between ECM terminal 35 and HO2S2 terminal 1. Refer to WIRING DIAGRAM .

      Continuity should exist. 

    5. Also check harness for short to ground and short to power.
      Fig 3: Identifying Oxygen Sensor 2 Harness Connector
      G04925811Courtesy of NISSAN MOTOR CO., U.S.A.

    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 terminals and HO2S2 terminal as follows.

      Refer to WIRING DIAGRAM .

      TERMINALS CONTINUITY CHART

      DTC Terminal Bank
      ECM Sensor
      P0137 33 4 1
      P0157 34 4 2

      Continuity should exist. 

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

      Refer to WIRING DIAGRAM .

      TERMINALS CONTINUITY CHART

      DTC Terminal Bank
      ECM Sensor
      P0137 33 4 1
      P0157 34 4 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 "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    : INSPECTION END 

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