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Home >> Infiniti >> 2019 >> Q70L 5.6 Luxe, AWD >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Steering Control System (DTC/Circuit Diagnosis) >> DTC/Circuit Diagnosis >> Vehicle Speed Signal Circuit >> Diagnosis Procedure
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Diagnosis Procedure

  1. PERFORM COMBINATION METER SELF-DIAGNOSIS 

    SYMBOL With CONSULT

    Perform self-diagnosis for "METER/M&A".

    Is any error system detected?

    YES

    Check the DTC. Refer to DTC Index .

    NO

    GO TO 2.

  2. CHECK VEHICLE SPEED SIGNAL CIRCUIT 
    1. Turn the ignition switch OFF.
    2. Disconnect power steering control unit harness connector.
    3. Disconnect combination meter harness connector.
    4. Check the continuity between combination meter harness connector and power steering control unit harness connector.

      Power steering control unit

      Combination meter

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      M108

      8

      M53

      3

      Existed

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair or replace damaged parts.

  3. CHECK VEHICLE SPEED SIGNAL (COMBINATION METER) 
    1. Connect combination meter harness connector.
    2. Check the combination meter input/output standard values. Refer to Reference Value .

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Replace combination meter. Refer to Removal and Installation .

  4. CHECK VEHICLE SPEED SIGNAL (POWER STEERING CONTROL UNIT) 
    1. Connect power steering control unit harness connector.
    2. Check the signal between power steering control unit harness connector and ground with oscilloscope.

      Power steering control unit

      --

      Condition

      Value (Approx.)

      Connector

      Terminal

      M108

      8

      Ground

      Vehicle speed: 40 km/h (25 MPH)

      CAUTION: Check the air pressure of tire under standard condition.
      GNSJSNIA0015GB-015Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Replace power steering control unit. Refer to Removal and Installation .

  5. CHECK TERMINALS AND HARNESS CONNECTORS 
    • Check the power steering control unit pin terminals for damage or loose connection with harness connector.
    • Check the combination meter pin terminals for damage or loose connection with harness connector.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Repair or replace damaged parts.