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Home >> Lexus >> 2020 >> LX 570 >> Repair and Diagnosis >> Steering >> Manual Steering >> Power Steering System (Diagnostics - Introduction) >> Power Steering System >> System Description [09/2015 - ] >> System Description [09/2015 - ]
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System Description [09/2015 - ]

  1. DESCRIPTION 
    1. In the Variable Flow Control (VFC) power steering system, the power steering ECU receives the steering angle signal, steering zero point memory, steering speed, vehicle speed signal, VGRS relative angle signal and engine speed signal through the CAN communication system. The power steering ECU also controls the variable flow control solenoid valve mounted on the vane pump assembly in accordance with whether the vehicle is driving straight or turning in order to supply an appropriate power steering fluid volume.

      Furthermore, without regard to whether or not the vehicle is being turned, if the power steering ECU cannot receive the steering angle signal, steering zero point memory, vehicle speed signal, VGRS relative angle signal or engine speed signal, the power steering warning light in the combination meter illuminates and the vehicle enters fail-safe mode. During fail-safe control, the resistance of the steering wheel increases drastically to inform the driver that the vehicle is in fail-safe mode.

  2. FUNCTION OF MAIN COMPONENTS 
    Item Function
    Power steering warning light Illuminates to inform the driver that a malfunction in the power steering system has occurred.
    Variable flow control solenoid valve Controls the power steering fluid volume according to the control signals from the power steering ECU.
    Power steering ECU Processes the signals sent from the skid control ECU, steering sensor, steering control ECU and ECM, and controls the variable flow control solenoid valve.
    Steering sensor Transmits the steering angle signal and steering zero point memory to the power steering ECU via CAN communication.
    Skid control ECU Transmits the vehicle speed signal to the power steering ECU via CAN communication.
    Steering control ECU Transmits the VGRS relative angle signal to the power steering ECU via CAN communication.
    ECM Transmits the engine speed signal to the power steering ECU via CAN communication.
    Drive mode select switch (integration control and panel assembly) Selects the driving mode.