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Home >> Infiniti >> 2012 >> G37 Base, 2D Convertible >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 130 (Steering Control System (Sedan)) >> DTC/Circuit Diagnosis >> Engine Speed Signal Circuit >> Diagnosis Procedure
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Diagnosis Procedure

WARNING: This page is about a different variant/trim than selected.
  1. PERFORM ECM SELF-DIAGNOSIS

    With CONSULT 

    Perform ECM self-diagnosis.

    Is any error system detected? 

    YES: Check the error system.

    NO: GO TO 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
      M107 110 M108 10 Existed

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

      Is the inspection result normal? 

      YES: GO TO 3.

      NO: Repair or replace damaged parts.

  3. CHECK ENGINE SPEED SIGNAL (1)
    1. Turn the ignition switch OFF.
    2. Connect ECM harness connectors.
    3. Check the signal between ECM harness connector and ground with oscilloscope.
      ECM Value (Approx.)
      Connector Terminal Condition
      M107 110 - Ground Engine speed: At idle (Warm-up condition)
      G04876941Courtesy of NISSAN NORTH AMERICA, INC.
      Engine speed: Approx. 2, 000 rpm (Warm-up condition)
      G04876942Courtesy of NISSAN NORTH AMERICA, INC.

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

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: Replace ECM. Refer to "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM): DESCRIPTION " (VQ37VHR), "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM): DESCRIPTION " (VQ25HR for USA and Canada),

  4. CHECK ENGINE SPEED SIGNAL (2)
    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 Value (Approx.)
      Connector Terminal Condition
      M108 10 - Ground Engine speed: At idle (Warm-up condition)
      G04876941Courtesy of NISSAN NORTH AMERICA, INC.
      Engine speed: Approx. 2, 000 rpm (Warm-up condition)
      G04876942Courtesy of NISSAN NORTH AMERICA, INC.

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

      Is the inspection result normal? 

      YES: GO TO 5.

      NO: Replace power steering control unit. Refer to "EXPLODED VIEW ".

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