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Home >> Infiniti >> 2005 >> G35 x >> Repair and Diagnosis >> Engine Performance >> Engine Control System - Sedan >> DTC P1278, P1288: 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: Locating Body Ground Connections
      G02348940Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 2.
    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: Locating A/F Sensor 1 (Bank 1, 2) And Heated Oxygen Sensor 2 (Bank 1, 2) Harness Connector
    G02348941Courtesy of NISSAN MOTOR CO., U.S.A.

    Tightening torque: 50 N.m (5.1 kg-m, 37 ft-lb) 

    1. : GO TO 3.
  3. CHECK EXHAUST GAS LEAK 
    1. Start engine and run it at idle.
    2. Listen for an exhaust gas leak before three way catalyst 1.
      Fig 3: Locating Exhaust Gas Leakage Before Three Way Catalyst 1
      G02348942Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Repair or replace.
  4. CHECK FOR INTAKE AIR LEAK 

    Listen for an intake air leak after the mass air flow sensor.

    OK or NG 

    1. OK: GO TO 5.
    2. NG: Repair or replace.
  5. 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" or "START"
    4. Run engine for at least 10 minutes at idle speed.

      Is the 1st trip DTC P0171, P172, P0174 or P0175 detected? 

      Is it difficult to start engine? 

      Fig 4: Identifying Self-Learning Cont Display In Work Support Mode
      G02348943Courtesy 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 P0171, P0172, P0174 or P0175 detected? 

      Is it difficult to start engine? 

    OK or NG 

    1. Yes: Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to "DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION " or "DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION ".
    2. No: GO TO 6.
      Fig 5: Locating Mass Air Flow Sensor With Intake Air Temperature Sensor
      G02348944Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect A/F sensor 1 harness connector.
      Fig 6: Locating A/F Sensor 1 (Bank 1, 2) Harness Connector
      G02348945Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Turn ignition switch ON.
    4. Check voltage between A/F sensor 1 terminal 3 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO  8.
    2. NG: GO TO 7.
      Fig 7: Checking Voltage Between A/F Sensor 1 Terminal 3 And Ground With Tester
      G02348946Courtesy of NISSAN MOTOR CO., U.S.A.
  7. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M72, F102
    • Harness connectors E108, M15
    • IPDM E/R harness connector E7
    • 15A fuse
    • Harness for open or short between A/F sensor 1 and fuse
    1. : Repair or replace harness or connectors.
  8. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between the following terminals. Refer to Wiring Diagram.
      Fig 8: A/F Sensor 1 Terminal And ECM Terminal Relating Table 1 (For Checking Continuity Between Terminals)
      G02348947Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should exist. 

    4. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
      Fig 9: A/F Sensor 1 Terminal And ECM Terminal Relating Table 2 (For Checking Continuity Between Terminals And Ground)
      G02348948Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should not exist. 

    5. Also check harness for short to power.

    OK or NG 

    1. OK: GO TO 9.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
  9. CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER 

    Refer to "Component Inspection ".

    OK or NG 

    1. OK: GO TO 10.
    2. NG: Replace A/F sensor 1.
  10. CHECK MASS AIR FLOW SENSOR 

    Refer to "Component Inspection ".

    OK or NG 

    1. OK: GO TO 11.
    2. NG: Replace mass air flow sensor.
  11. CHECK PCV VALVE 

    Refer to "POSITIVE CRANKCASE VENTILATION ".

    OK or NG 

    1. OK: GO TO 12.
    2. NG: Repair or replace PCV valve.
  12. CHECK INTERMITTENT INCIDENT 

    Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG 

    1. OK: Replace A/F sensor 1.
    2. NG: Repair or replace.
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