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Home >> Infiniti >> 2007 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0137 To P0448 >> DTC P0181 FTT Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK COMBINATION METER FUNCTION 

    Refer to "COMBINATION METERS ".

    OK or NG 

    OK: GO TO 2.

    NG: Go to "FUEL LEVEL SENSOR UNIT INSPECTION ".

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

      Refer to "GROUND INSPECTION ".

      Fig 1: Checking Ground Connections
      G04900129Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 3.

    NG: Repair or replace ground connections.

  3. CHECK FUEL TANK TEMPERATURE SENSOR POWER SUPPLY CIRCUIT 
    1. Disconnect "fuel level sensor unit and fuel pump" harness connector.
    2. Turn ignition switch ON.
      Fig 2: Checking Fuel Pump Power Supply And Ground
      G04900370Courtesy of NISSAN NORTH AMERICA, INC.
    3. Check voltage between "fuel level sensor unit and fuel pump" terminal 4 and ground with CONSULT-II or tester.

      Voltage: Approximately 5V 

    OK or NG 

    OK: GO TO  5.

    NG: GO TO 4.

    Fig 3: Checking Voltage Between Fuel Level Sensor Unit And Fuel Pump Terminal 4 And Ground
    G04875130Courtesy of NISSAN NORTH AMERICA, INC.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors C1, E41
    • Harness for open or short between ECM and "fuel level sensor unit and fuel pump"

    Repair harness or connector.

  5. CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect combination meter harness connector.
    3. Check harness continuity between "fuel level sensor unit and fuel pump" terminal 3 and combination meter terminal 16. Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  7.

    NG: GO TO 6.

  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors C1, E41
    • Harness connectors E152, M31
    • Harness for open or short between "fuel level sensor unit and fuel pump" and combination meter

    Repair open circuit or short to ground or short to power in harness or connector.

  7. CHECK FUEL TANK TEMPERATURE SENSOR 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 8.

    NG: Replace "fuel level sensor unit and fuel pump".

  8. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    INSPECTION END 

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