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Home >> Infiniti >> 2009 >> G37 Base, 4D Sedan >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Power Steering Control System -- Sedan >> With 4WAS >> Component Diagnosis >> DTC C1631, C1632: 4WAS Front Control Unit >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK 4WAS FRONT CONTROL UNIT POWER SUPPLY
    1. Turn the ignition switch OFF.
    2. Disconnect 4WAS front control unit harness connector.
    3. Check the voltage between 4WAS front control unit harness connector terminal and ground.
      CONNECTOR TERMINAL VOLTAGE CHART

      4WAS front control unit Voltage (Approx.)
      Connector Terminal
      M41 11 - Ground Battery voltage
      M42 15 - Ground 0 V
    4. Turn the ignition switch ON.
      CAUTION: Never start the engine.
    5. Check the voltage between 4WAS front control unit harness connector terminal and ground.
      CONNECTOR TERMINAL VOLTAGE CHART

      4WAS front control unit Voltage (Approx.)
      Connector Terminal
      M41 11 - Ground Battery voltage
      M42 15 - Ground

      Is the inspection result normal? 

      YES: GO TO 2.

      NO: Check the following items. Repair or replace the malfunctioning parts.

      • 40A fusible link (#I) open
        • Short among 40A fusible link (#I) connector, 4WAS front control unit harness connector No. 11 terminal and the ground
      • Open between the battery and 4WAS front control unit harness connector No. 11 terminal
      • 10A fuse (#3) open
        • Short among 10A fuse (#3) connector, 4WAS front control unit harness connector No. 15 terminal and the ground
        • Short among 10A fuse (#3) connector, unified meter and A/C amp harness connector No. 53 terminal and the ground
      • Open between the ignition switch and 4WAS front control unit harness connector No. 15 terminal
      • Battery or ignition switch
  2. CHECK 4WAS FRONT CONTROL UNIT GROUND

    Check the continuity between 4WAS front control unit harness connector terminal and the ground.

    CONNECTOR TERMINAL CONTINUITY CHART

    4WAS front control unit Continuity
    Connector Terminal
    M41 12 - Ground Existed
    M42 18 - Ground
    34 - Ground

    Is the inspection result normal? 

    YES: GO TO 3.

    NO: Repair or replace the harnesses and connectors.

  3. CHECK TERMINAL

    Check 4WAS front control unit harness connector pin terminal and connection for disconnection.

    Is the inspection result normal? 

    YES: GO TO 4.

    NO: Repair or replace the specific malfunctioning part.

  4. CHECK INFORMATION
    • Check that any item below is applicable when the malfunctions occur.
      • The engine stall occurs while driving or stopping the vehicle.
      • When detecting the charging system error

        Is the item applicable? 

        YES: Check the error system.

        • Perform ECM symptom diagnosis. Refer to "SYMPTOM TABLE ".
        • Perform the symptom diagnosis for the charging system. Refer to "SYMPTOM TABLE ".

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