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Home >> Infiniti >> 2014 >> Q60 Base, 2D Convertible, Standard Trans >> Repair and Diagnosis >> Steering >> Manual Steering >> Steering Control System (Convertible) >> DTC/Circuit Diagnosis >> Engine Speed Signal Circuit >> Diagnosis Procedure
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Diagnosis Procedure

  1. PERFORM ECM SELF-DIAGNOSIS 

    With CONSULT 

    1. Turn the ignition switch ON.
      CAUTION: Never start the engine
    2. Perform "ENGINE" self-diagnosis. Refer to "CONSULT FUNCTION ".

      Is any DTC detected? 

      YES: Check the DTC.

      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
    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 3.

      NO: Repair or replace error-detected parts.

  3. CHECK ENGINE SPEED SIGNAL (1) 
    1. Connect ECM harness connectors.
    2. Turn the ignition switch ON.
    3. Check the signal between ECM harness connector and ground with oscilloscope.
      ECM - Condition Voltage (Approx.)
      Connector Terminal
      M107 110 Ground Engine is running
      • Warm-up condition
      • Idle speed
      G05729712
      Engine is running
      • Warm-up condition
      • Engine speed: Approx. 2, 000 rpm
      G05729713

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: Replace ECM. Refer to "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT (ECM): DESCRIPTION ".

  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 - Condition Voltage (Approx.)
      Connector Terminal
      M108 10 Ground Engine is running
      • Warm-up condition
      • Idle speed
      G05729712
      Engine is running
      • Warm-up condition
      • Engine speed: Approx. 2, 000 rpm
      G05729713

      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 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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