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Home >> Infiniti >> 2008 >> G37 Base >> Repair and Diagnosis >> Steering >> Manual Steering >> Steering Control System (With 4WAS) >> Component Diagnosis >> DTC C1909: 4WAS Main Control Unit >> Diagnosis Procedure
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Diagnosis Procedure

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

      4WAS main control unit Voltage (Approx.)
      Connector Terminal
      B54 27 - Ground 0 V
    4. Turn the ignition switch ON.
      CAUTION: Never start the engine.
    5. Check the voltage between 4WAS main control unit harness connector terminal and the ground.
    VOLTAGE REFERENCE CHART

    4WAS main control unit Voltage (Approx.)
    Connector Terminal
    B54 27 - Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO  2.

    NG: Check the following items. Repair or replace the malfunctioning parts.

    • 10A fuse (#45) open
    • Short among 10A fuse (#45) connector, 4WAS main control unit harness connector No. 27 terminal and the ground
    • Open between the ignition switch and 4WAS main control unit harness connector No. 27 terminal
    • Ignition switch
  2. CHECK 4WAS MAIN CONTROL UNIT GROUND

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

    CONTINUITY REFERENCE CHART

    4WAS main control unit Continuity
    Connector Terminal
    B54 34 - Ground Existed

    Is the inspection result normal? 

    YES: GO TO  3.

    NG: Repair or replace the harnesses and connectors.

  3. PERFORM SELF-DIAGNOSIS (4WAS MAIN CONTROL UNIT)

    With CONSULT-III 

    1. Connect 4WAS main control unit harness connector.
    2. Perform 4WAS main control unit self-diagnosis.

    Is DTC "C1909" detected? 

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

    NO: GO TO  4.

  4. CHECK INFORMATION

    With CONSULT-III 

    Check the "DATA MONITOR" value of each DTC detected with the self-diagnosis function. Refer to "REFERENCE VALUE ".

    Is each data the standard value? 

    YES: Check each harness connector pin terminal for disconnection.

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