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Home >> Infiniti >> 2017 >> QX80 Base, AWD >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Circuit Diagnosis >> Engine Speed Signal Circuit >> Diagnosis Procedure >> Diagnostic Test

Diagnostic Test

  1. PERFORM ECM SELF-DIAGNOSIS

    G-20With CONSULT 

    Perform "ENGINE"self-diagnosis.

    Is any DTC detected?

    YES 

    Check the DTC. Refer to DTC INDEX .

    NO 

    GO TO STEP 2. 

  2. CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT

    1. Turn the ignition switch OFF.
    2. Disconnect ECM harness connectors.
    3. Disconnect power steering control unit harness connector.
    4. Check the continuity between ECM harness connector and power steering control unit harness connector.
      ECM Power steering control unit Continuity
      Connector Terminal Connector Terminal
      E20 126 M108 10 Existed
    5. Check the continuity between power steering control unit harness connector and ground.
      Power steering control unit - Continuity
      Connector Terminal
      M108 10 Ground Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 3. 

    NO 

    Repair or replace error-detected parts.

  3. CHECK ENGINE SPEED SIGNAL (ECM)

    1. Connect ECM harness connectors.
    2. Check the signal between ECM harness connector and ground with oscilloscope.
      ECM - Condition Voltage (Approx.)
      Connector Terminal
      E20 126 Ground Engine is running
      • Warm-up condition
      • Idle speed
      GNSJPBIA3352ZZ-352Courtesy of NISSAN NORTH AMERICA, INC.
      Engine is running
      • Warm-up condition
      • Engine speed: Approx. 2, 000 rpm
      GNSJPBIA3354ZZ-354Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES 

    GO TO STEP 4. 

    NO 

    Replace ECM. Refer to DESCRIPTION .

  4. CHECK ENGINE SPEED SIGNAL (POWER STEERING CONTROL UNIT)

    1. Turn the ignition switch OFF.
    2. Connect power steering control unit harness connector.
    3. Check the signal between power steering control unit harness connector and ground with oscilloscope.
    Power steering control unit - Condition Voltage (Approx.)
    Connector Terminal
    M108 10 Ground Engine is running
    • Warm-up condition
    • Idle speed
    GNSJPBIA3352ZZ-352Courtesy of NISSAN NORTH AMERICA, INC.
    Engine is running
    • Warm-up condition
    • Engine speed: Approx. 2, 000 rpm
    GNSJPBIA3354ZZ-354Courtesy of NISSAN NORTH AMERICA, INC.

    Is the inspection result normal?

    YES 

    GO TO STEP 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 ECM pin terminals for damage or loose connection with harness connector.

    Is the inspection result normal?

    YES 

    INSPECTION END

    NO 

    Repair or replace error-detected parts.

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