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 behavior.

    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)


      1. The VSC (Cooperative Control with EPS) performs 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. Downhill Assist Control*2


      1. The downhill assist control is used when driving downhill on a sharp slope on which the engine brake alone will not adequately decelerate the vehicle. The driver can operate the downhill assist control switch while the shift range is in L or R, in order to automatically control the brake hydraulic pressure to the four wheels.

  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 assembly.
    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.
    VSC OFF Switch Enables the driver to select the Normal mode, TRC off mode, or VSC off mode.
    Downhill Assist Control Switch*2 Allows the driver to turn downhill assist control on and off.
    Stop Light Switch Assembly Detects the brake pedal depressing signal.
    Main Body ECU (Multiplex Network Body ECU) Transmits the parking brake switch signal to the skid control ECU.
    Parking Brake Switch Assembly Detects the parking brake pedal status.
    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.
    Airbag Sensor Assembly Yaw Rate and Acceleration Sensor

    • Detects the vehicle's longitudinal and lateral acceleration.

    • Detects the vehicle's yaw rate.

    • The airbag sensor assembly sends the detection signals from the yawrate sensor and acceleration sensor to the skid control ECU via CAN communication.
    Steering Angle Sensor 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

    • 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.
    Multi-information Display

    • Displays an information message when TRC OFF mode is selected.

    • Displays a warning message when the skid control ECU detects a malfunction in the ABS or EBD.
    Downhill Assist Control Indicator Light*2

    • Illuminates to inform the driver when downhill assist control operation is possible.

    • When the downhill assist control switch is on but not all operating conditions are met, the downhill assist control indicator light blinks to inform the driver.
    Brake Master Cylinder Reservoir Sub-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.
    Stop Light Control Relay (STOP LP Relay)*1 Illuminates or flashes the stop lights in accordance with the signals from the stop light switch assembly and skid control ECU.
    Power Steering ECU Assembly Controls the steering assist torque based on the signals received from the skid control ECU.
    Meter buzzer Intermittently sounds to inform the driver if the temperature of the brake actuator assembly has increased excessively due to continuous operation of the downhill assist control (for AWD).

    *1: w/ Downhill Assist Control or Dynamic Radar Cruise Control

    *2: for AWD