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Home >> Infiniti >> 2009 >> G37 x, 4D Sedan >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Power Steering Control System -- Sedan >> With 4WAS >> Component Diagnosis >> DTC C1633: 4WAS Front Control Unit >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK 4WAS FRONT CONTROL UNIT (1)

    With CONSULT-III 

    1. Start the engine.
      CAUTION: Stop the vehicle.
    2. Check "THERM TEMP" on "DATA MONITOR" of 4WAS front control unit.
    3. Steer the steering wheel 360° leftward slowly and then steer 360° rightward. Return the steering wheel to the straight-ahead position. Repeat the same service for 3 minutes.
    4. Check "THERM TEMP" on "DATA MONITOR" of 4WAS front control unit.

      Is DATA MONITOR value difference between before and after the service 3° or less? 

      YES: Replace 4WAS front control unit. Refer to "EXPLODED VIEW ".

      NO: GO TO 2.

  2. CHECK 4WAS FRONT CONTROL UNIT (2)

    With CONSULT-III 

    1. Start the engine.
      CAUTION: Stop the vehicle.
    2. Check "THERM TEMP" item on "DATA MONITOR" of 4WAS front control unit.
    3. Steer the steering wheel 360° leftward slowly and then steer 360° rightward. Return the steering wheel to the straight-ahead position. Repeat the same service for 3 minutes.
    4. Check "THERM TEMP" item on "DATA MONITOR" of 4WAS front control unit.
      MONITOR ITEM DESCRIPTION

      Monitor item Condition Display value
      THERM TEMP Engine running (idling) -40 - 100°C

      Is the inspection result normal? 

      YES: GO TO 3.

      NO: Replace 4WAS front control unit. Refer to "EXPLODED VIEW ".

  3. CHECK INFORMATION
    • Check that any item below is applicable when malfunction occurs.
      • Entering and exiting the garage (Frequent steering)
      • When steering the steering wheel for a long time

        Is the item applicable? 

        YES: 4WAS system protection function mode (overheat protection) (4WAS system temporary stop)

        NO: Replace 4WAS front control unit. Refer to "EXPLODED VIEW ".