VEHICLE STABILITY CONTROL SYSTEM SYSTEM DESCRIPTION


  1. FUNCTION DESCRIPTION


    1. Anti-lock Brake System (ABS)


      1. The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking on a slippery surface.

    2. Electronic Brake Force Distribution (EBD)


      1. The EBD utilizes ABS, achieving proper brake force distribution between the front and rear wheels in accordance with the driving conditions. In addition, during braking while cornering, the EBD also controls the brake forces of the right and left wheels, helping maintain vehicle stability.

    3. Brake Assist (BA)


      1. The primary purpose of brake assist is to provide an auxiliary brake force to assist a driver who cannot generate a large brake force during emergency braking, thus helping ensure the vehicle's braking performance.

      2. If the brake booster malfunctions and the skid control ECU judges that the brake pedal force applied by the driver is not sufficient to ensure adequate braking force, brake assist is used to enhance the braking force.

    4. Traction Control (TRC)


      1. The TRC helps restrain the slippage of the drive wheels if the driver depresses the accelerator pedal excessively when starting off or while accelerating on a slippery surface.

    5. Vehicle Stability Control (VSC)


      1. The VSC helps restrain sideways slippage of the vehicle during a strong front wheel skid or strong rear wheel skid, which may occur while cornering.

    6. VSC (Cooperative Control with EPS) / VSC+


      1. Effects cooperative control with the power steering ECU assembly in order to provide steering assist in accordance with the operating conditions of the vehicle.

    7. Hill-start Assist Control


      1. When starting uphill, this control maintains the brake hydraulic pressure on all 4 wheels, in order to momentarily prevent the vehicle from descending backward.

    8. Emergency Brake Signal


      1. In the case of emergency braking, the emergency brake signal flashes the stop lights to alert the drivers in following vehicle.

    9. Brake Hold System


      1. The brake hold operation occurs when the brake pedal is depressed and the vehicle is fully stopped. Under brake hold, the wheel cylinder oil pressure of the 4 wheels is maintained, and the vehicle's fully stopped condition is sustained. When the acceleration pedal is depressed, the wheel cylinder oil pressure is automatically released. Also, depending on the vehicle conditions, the electric parking brake operates.

  2. FUNCTION OF COMPONENTS

    Component Function
    Brake Actuator Assembly Skid Control ECU

    • Judges the vehicle driving condition based on the signals from each sensor, and sends the brake control signals to the brake actuator.

    • Based on signals from various sensors, outputs the emergency brake signal control signals.
    Master Cylinder Pressure Sensor Assembled in the brake actuator assembly, detects the master cylinder pressure.
    Pump Motor Drives the pumps inside the brake actuator assembly.
    Solenoid Valves Change the fluid path based on the signals from the skid control ECU during the operation of the brake control system functions in order to control the fluid pressure applied to each wheel cylinder.
    Skid Control ECU ABS Motor Relay Supplies power to the pump motor.
    ABS Solenoid Relay Supplies power to the solenoid valves.
    Speed Sensor Detects the wheel speed of each of the 4 wheels.
    Integration Control and Panel Assembly VSC OFF Switch Enables the driver to select the Normal mode, TRC off mode, or VSC off mode.
    Air Conditioning Control Assembly Hazard Warning Signal Switch Transmits a hazard warning light on/off request signal to the skid control ECU.
    Stop Light Switch Assembly Detects when the brake pedal is depressed.
    Parking Brake ECU Assembly

    • Sends the electric parking brake condition to the skid control ECU.

    • Controls the parking brake actuator assembly based on the signals received from the skid control ECU.
    ECM

    • Sends the throttle position signal, accelerator pedal position signal, engine speed signal etc., to the skid control ECU.

    • Controls the engine output based on the signals received from the skid control ECU.
    Acceleration Sensor (Yaw Rate Sensor)

    • Detects the vehicle's longitudinal and lateral acceleration.

    • Detects the vehicle's yaw rate.
    Steering Angle Sensor (Spiral Cable with Sensor Sub-assembly) Detects the steering direction and angle of the steering wheel.
    Combination Meter Assembly ABS Warning Light Illuminates to alert the driver when the skid control ECU detects a malfunction in the ABS.
    Brake Warning Light (Red Indicator)

    • Illuminates to alert the driver when the skid control ECU detects a malfunction in the EBD.

    • Illuminates to alert the driver when the brake fluid level is low.
    VSC OFF Indicator Light Illuminates to inform the driver when VSC OFF mode is selected.
    Slip Indicator Light

    • Blinks to inform the driver when the TRC and VSC are operational.

    • Illuminates to alert the driver when the skid control ECU detects a malfunction in the TRC or VSC.
    TRC OFF Indicator Light Illuminates to inform the driver when TRC OFF mode is selected.
    Multi-information Display Displays a warning message when the skid control ECU detects a malfunction in the ABS or EBD.
    Brake Hold Standby Indicator Light Comes on when the system is in the brake hold control permission state.
    Brake Hold Operated Indicator Light

    • Comes on when the brake hold is operating.

    • Blinks when a malfunction has occurred during brake hold control selection.
    Brake Master Cylinder Reservoir Assembly Brake Fluid Level Warning Switch Detects the brake fluid level.
    Brake Pedal Support Assembly Brake Pedal Load Sensing Switch Detects the brake pedal load.
    No. 2 Integration Relay

    • Illuminates or flashes the stop lights in accordance with the signals from the stop light switch assembly and skid control ECU.

    • Illuminates the stop lights while brake hold control is operating.
    Power Steering ECU Assembly Controls the steering assist torque based on the signals received from the skid control ECU.
    Roll Rate and Vertical Acceleration Sensor (Yaw Rate Sensor) Detects the vehicle's vertical acceleration.
    Brake hold switch (Satellite switch set) Permits the brake hold operation.