LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2021 >> Altima S >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (Pr25DD) (DTC/Circuit Diagnosis) (1 Of 4) >> DTC/Circuit Diagnosis >> DTC P0136: O2 Sensor 2 Bank 1 >> DTC Diagnosis Procedure >> PR25DD engine
April 5, 2026: LEMON Manuals is launched! Read the announcement.

PR25DD engine

  1. INSPECTION START 

    Confirm the detected malfunction (A or B). DTC Description 

    Which malfunction is detected?

    A

    GO TO 2.

    B

    GO TO 7.

  2. CHECK HO2S2 CONNECTOR FOR WATER 
    1. Turn ignition switch OFF.
    2. Disconnect heated oxygen sensor 2 harness connector.
    3. Check connectors for water.

    Water should not exist.

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair or replace error-detected parts.

  3. CHECK HO2S2 GROUND CIRCUIT 
    1. Disconnect ECM harness connector.
    2. Check the continuity between HO2S2 harness connector and ECM harness connector.

      +

      -

      Continuity

      HO2S2

      ECM

      Connector

      Terminal

      Connector

      Terminal

      E78

      4

      F90

      76

      Existed

    3. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Repair or replace error-detected parts.

  4. CHECK HO2S2 INPUT SIGNAL CIRCUIT 
    1. Check the continuity between HO2S2 harness connector and ECM harness connector.

      +

      -

      Continuity

      HO2S2

      ECM

      Connector

      Terminal

      Connector

      Terminal

      E78

      3

      F90

      77

      Existed

    2. Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.

      +

      -

      Continuity

      HO2S2

      Connector

      Terminal

      E78

      3

      Ground

      Not existed

      +

      -

      Continuity

      ECM

      Connector

      Terminal

      F90

      77

      Ground

      Not existed

    3. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Repair or replace error-detected parts.

  5. CHECK HEATED OXYGEN SENSOR 2 

    Check the heated oxygen sensor 2. Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Inspection .

    NO

    GO TO 6.

  6. REPLACE HEATED OXYGEN SENSOR 2 

    Replace heated oxygen sensor 2. Refer to Exploded View (AWD MODELS WITH PR25DD ENGINE), Exploded View (FWD MODELS WITH PR25DD ENGINE).

    INSPECTION END

  7. CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE CLEAR 
    1. Clear the mixture ratio self-learning value clear. Refer to Work Procedure .
    2. Run engine for at least 10 minutes at idle speed.

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

    YES

    Perform trouble diagnosis for DTC P0172. DTC Description 

    NO

    GO TO 8.

  8. CHECK HO2S2 GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect heated oxygen sensor 2 harness connector.
    3. Disconnect ECM harness connector.
    4. Check the continuity between HO2S2 harness connector and ECM harness connector.

      +

      -

      Continuity

      HO2S2

      ECM

      Connector

      Terminal

      Connector

      Terminal

      E78

      4

      F90

      76

      Existed

    5. Also check harness for short to ground and to power.

    Is the inspection result normal?

    YES

    GO TO 9.

    NO

    Repair or replace error-detected parts.

  9. CHECK HO2S2 INPUT SIGNAL CIRCUIT 
    1. Check the continuity between HO2S2 harness connector and ECM harness connector.

      +

      -

      Continuity

      HO2S2

      ECM

      Connector

      Terminal

      Connector

      Terminal

      E78

      3

      F90

      77

      Existed

    2. Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.

      +

      -

      Continuity

      HO2S2

      Connector

      Terminal

      E78

      3

      Ground

      Not existed

      +

      -

      Continuity

      ECM

      Connector

      Terminal

      F90

      77

      Ground

      Not existed

    3. 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 HEATED OXYGEN SENSOR 2 

    Check the heated oxygen sensor 2. Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Inspection .

    NO

    GO TO 11.

  11. REPLACE HEATED OXYGEN SENSOR 2 

    Replace heated oxygen sensor 2. Refer to Exploded View (AWD MODELS WITH PR25DD ENGINE), Exploded View (FWD MODELS WITH PR25DD ENGINE).

    INSPECTION END