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Home >> Infiniti >> 2015 >> QX50 Base, AWD >> Repair and Diagnosis (Single Page) >> Steering >> Steering Control Systems >> Steering Control System (EPS) >> DTC/Circuit Diagnosis >> Vehicle Speed Signal Circuit >> Diagnosis Procedure >> Diagnostic Test
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Diagnostic Test

  1. PERFORM UNIFIED METER AND A/C AMP. SELF-DIAGNOSIS

    With CONSULT 

    1. Turn the ignition switch ON.
    2. Perform "METER/M&A" self-diagnosis. Refer to CONSULT FUNCTION (METER/M&A) .

    Is any DTC detected?

    YES 

    Check the DTC.

    NO 

    GO TO STEP 2. 

  2. CHECK HARNESS BETWEEN UNIFIED METER AND A/C AMP. AND POWER STEERING CONTROL UNIT

    1. Turn the ignition switch OFF.
    2. Disconnect unified meter and A/C amp. harness connector.
    3. Disconnect power steering control unit harness connector.
    4. Check continuity between unified meter and A/C amp. harness connector and power steering control unit harness connector.
      Unified meter and A/C amp. Power steering control unit Continuity
      Connector Terminal Connector Terminal
      M66 8 M108 8 Existed
    5. Check continuity between power steering control unit harness connector and ground.
      Power steering control unit - Continuity
      Connector Terminal
      M108 8 Ground Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 3. 

    NO 

    Repair or replace damaged parts.

  3. CHECK VEHICLE SPEED SIGNAL (1)

    1. Connect unified meter and A/C amp. harness connector.
    2. Check unified meter and A/C amp. input/output standard values. Refer to REFERENCE VALUE .

    Is the inspection result normal?

    YES 

    GO TO STEP 4. 

    NO 

    Replace unified meter and A/C amp. Refer to EXPLODED VIEW .

  4. CHECK VEHICLE SPEED SIGNAL (2)

    1. Turn the ignition switch OFF.
    2. Connect power steering control unit harness connector.
    3. Check signal between power steering control unit harness connector and ground with oscilloscope.
      Power steering control unit - Condition Voltage (Approx.)
      Connector Terminal
      M108 8 Ground Vehicle speed: 40 km/h (25 MPH)
      CAUTION:

      Check air pressure of tire under standard condition.
      NOTE:

      The maximum voltage varies depending on the specification (destination unit).

      GNSJSNIA0015GB-015Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES 

    GO TO STEP 5. 

    NO 

    Replace power steering control unit. Refer to EXPLODED VIEW .

  5. CHECK TERMINALS AND HARNESS CONNECTORS

    • Check power steering control unit pin terminals for damage or loose connection with harness connector.
    • Check unified meter and A/C amp. pin terminals for damage or loose connection with harness connector.

    Is the inspection result normal?

    YES 

    INSPECTION END

    NO 

    Repair or replace damaged parts.

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