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Home >> Infiniti >> 2008 >> G37 Base >> Repair and Diagnosis >> Steering >> Manual Steering >> Steering Control System (With 4WAS) >> Component Diagnosis >> DTC C1684, C1685: 4WAS Main Control Unit Communication >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK COMMUNICATION LINE (1)
    1. Turn the ignition switch OFF.
    2. Disconnect ABS actuator and electric unit (control unit) harness connector.
    3. Disconnect yaw rate/side G sensor harness connector.
    4. Disconnect 4WAS front control unit harness connector.
    5. Disconnect 4WAS main control unit harness connector.
    6. Check the continuity between ABS actuator and electric unit (control unit) harness connector and yaw rate/side G sensor harness connector.
    CONTINUITY REFERENCE CHART

    ABS actuator and electric unit (control unit) Yaw rate/side G sensor. Continuity
    Connector Terminal Connector Terminal
    E41 25 M143 2 Existed
    45 3

    Is the inspection result normal? 

    YES: GO TO  2.

    NO: Repair or replace the harnesses and connectors. Refer to "PRECAUTIONS FOR HARNESS REPAIR ".

  2. CHECK COMMUNICATION LINE (2)

    Check the continuity between ABS actuator and electric unit (control unit) harness connector and the ground.

    CONTINUITY REFERENCE CHART

    ABS actuator and electric unit (control unit) Continuity
    Connector Terminal
    E41 25 - Ground Not existed
    45 - Ground

    Is the inspection result normal? 

    YES: GO TO  3.

    NO: Repair or replace the harnesses and connectors. Refer to "PRECAUTIONS FOR HARNESS REPAIR ".

  3. CHECK COMMUNICATION LINE (3)

    Check the continuity between ABS actuator and electric unit (control unit) harness connector.

    CONTINUITY REFERENCE CHART

    ABS actuator and electric unit (control unit) Continuity
    Connector Terminal
    E41 25 - 45 Not existed

    Is the inspection result normal? 

    YES: GO TO  4.

    NO: Repair or replace the harnesses and connectors. Refer to "PRECAUTIONS FOR HARNESS REPAIR ".

  4. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)

    Check the continuity between ABS actuator and electric unit (control unit) connector. Refer to "COMPONENT INSPECTION [ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)] ".

    Is the inspection result normal? 

    YES: GO TO  5.

    NO: Replace ABS actuator and electric unit (control unit). Refer to "EXPLODED VIEW ".

  5. CHECK YAW RATE/SIDE G SENSOR

    Check the continuity between yaw rate/side G sensor connector. Refer to "COMPONENT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO  6.

    NO: Replace yaw rate/side G sensor. Refer to "EXPLODED VIEW ".

  6. CHECK CAN DIAGNOSIS SUPPORT MONITOR (4WAS FRONT CONTROL UNIT)

    With CONSULT-III 

    1. Connect ABS actuator and electric unit (control unit) harness connector.
    2. Connect yaw rate/side G sensor harness connector.
    3. Connect 4WAS front control unit harness connector.
    4. Connect 4WAS main control unit harness connector.
    5. Start the engine.
      CAUTION: Stop the vehicle.
    6. Perform CAN diagnosis support monitor of 4WAS front control unit.
    7. Replace 4WAS main control unit error history. Refer to "CONSULT-III FUNCTION [4WAS(FRONT)] ".

    What is the indicated item? 

    All items are "OK": GO TO  7.

    "TRANSMIT DIAG" is other than "OK": GO TO  7.

    "4WAS(MAIN)" is other than "OK": GO TO  8.

  7. CHECK 4WAS FRONT CONTROL UNIT CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect 4WAS front control unit harness connector.
    3. Disconnect ABS actuator and electric unit (control unit) harness connector.
    4. Check the continuity between 4WAS front control unit harness connector and ABS actuator and electric unit (control unit) harness connector.
      CONTINUITY REFERENCE CHART

      4WAS front control unit ABS actuator and electric unit (control unit) Continuity
      Connector Terminal Connector Terminal
      M42 14 E41 25 Existed
      25 45
    5. Check that 4WAS front control unit connector No. 14 terminal and No. 25 are connected properly and not deformed.

    Is the inspection result normal? 

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

    NO: Repair or replace the harnesses and connectors. Refer to "PRECAUTIONS FOR HARNESS REPAIR ".

  8. CHECK 4WAS MAIN CONTROL UNIT CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect 4WAS main control unit harness connector.
    3. Disconnect ABS actuator and electric unit (control unit) harness connector.
    4. Check the continuity between 4WAS main control unit harness connector and ABS actuator and electric unit (control unit) harness connector.
      CONTINUITY REFERENCE CHART

      4WAS main control unit ABS actuator and electric unit (control unit) Continuity
      Connector Terminal Connector Terminal
      B54 31 E41 45 Existed
      32 25
    5. Check that 4WAS main control unit connector No. 31 terminal and No. 32 are connected properly and not deformed.

    Is the inspection result normal? 

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

    NO: Repair or replace the harnesses and connectors. Refer to "PRECAUTIONS FOR HARNESS REPAIR ".

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