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Home >> Nissan-Datsun >> 2005 >> Murano SL, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P1274, P1284: A/F Sensor 1 >> Diagnostic Procedure
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Diagnostic Procedure

  1. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF. 
    2. Loosen and retighten two ground screws on the body. Refer to GROUND INSPECTION .
      Fig 1: Checking Ground Connections
      G02466636Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO  2.
    • NG: Repair or replace ground connections.
  2. RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1 

    Loosen and retighten the air fuel ratio (A/F) sensor 1.

    Fig 2: Retightening Air Fuel Ratio (A/F) Sensor 1
    G02466637Courtesy of NISSAN MOTOR CO., U.S.A.
    • Tightening torque: 40 - 60 N-m (4.1 - 6.1 kg-m, 30 - 44 ft-lb) 
    • GO TO  3.
  3. CLEAR THE SELF-LEARNING DATA. 

    WITH CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Select "SELF-LEARNING CONT" in "WORK SUPPORT" mode with CONSULT-II.
    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 P0172 or P0175 detected? 

      Is it difficult to start engine? 

      Fig 3: CONSULT-II Work Support Screen
      G02466638Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Turn ignition switch OFF.
    3. Disconnect mass air flow sensor harness connector.
    4. Restart engine and let it idle for at least 5 seconds.
    5. Stop engine and reconnect mass air flow sensor harness connector.
    6. Make sure DTC P0102 is displayed.
    7. Erase the DTC memory. Refer to HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION .
    8. Make sure DTC P0000 is displayed.
    9. 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 or No 

    Fig 4: Disconnecting Mass Air Flow Sensor Harness Connector
    G02466639Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK HARNESS CONNECTOR 
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector.
      Fig 5: Disconnecting A/F Sensor 1 Harness Connector
      G02466640Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check harness connector for water.

      Water should not exit. 

    OK or NG 

    • OK: GO TO  5.
    • NG: Repair or replace harness connector.
  5. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT 
    1. Turn ignition switch ON.
    2. Check voltage between A/F sensor 1 terminal 3 and ground with CONSULT-II or tester.
      • Voltage: Battery voltage 

    OK or NG 

    • OK: GO TO  11.
    • NG: GO TO  6.
    Fig 6: Checking Voltage Between A/F Sensor 1 Terminal & Ground
    G02466641Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK CONDENSER CIRCUIT-I 
    1. Turn ignition switch OFF.
    2. Disconnect fuse block (J/B) harness connector M1.
    3. Check resistance between fuse block (J/B) terminal 9A and ground. Refer to WIRING DIAGRAM .
      • Resistance: Above 1 MΩ at 25°C (77°F) 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    • OK: GO TO  7.
    • NG: GO TO  8.
  7. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M82, F102
    • Fuse block (J/B) connector M1
    • 15A fuse
    • Harness for open or short between A/F sensor 1 and fuse
      • Repair harness or connectors.
  8. CHECK CONDENSER CIRCUIT-II 
    1. Disconnect condenser harness connectors.
    2. Check harness continuity between fuse block (J/B) terminal 9A and condenser terminal 1, condenser terminal 2 and ground.

      Refer to WIRING DIAGRAM .

      • Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    • OK: GO TO  9.
    • NG: Repair harness or connectors.
  9. CHECK CONDENSER 

    Refer to CONDENSER .

    OK or NG 

    • OK: GO TO  10.
    • NG: Replace condenser.
  10. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    • INSPECTION END 
  11. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
      Fig 7: A/F Sensor 1 Terminal & ECM Terminal Continuity Chart
      G02466642Courtesy of NISSAN MOTOR CO., U.S.A.
      • Continuity should exist. 
    4. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM .
      BANK 1 AND BANK 2 REFERENCE

      Bank 1 Bank 2
      A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal
      1 16 1 76
      2 75 2 77
      5 35 5 57
      6 56 6 58
      • Continuity should not exist. 
    5. Also check harness for short to power.

    OK or NG 

    • OK: GO TO  12.
    • NG: Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK A/F SENSOR 1 HEATER 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    • OK: GO TO  13.
    • NG: Replace A/F sensor 1.
  13. CHECK INTERMITTENT INCIDENT 

    Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    OK or NG 

    • OK: Go to  14.
    • NG: Repair or replace.
  14. REPLACE AIR FUEL RATIO (A/F) SENSOR 1 

    Replace air fuel ratio (A/F) sensor 1.

    CAUTION:
    • Discard any air fuel ratio (A/F) 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 air fuel ratio (A/F) sensor, clean exhaust system threads using Heated Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant. 
    • INSPECTION END
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