PRE-CRASH SAFETY SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Item Function
    Millimeter Wave Radar Sensor Assembly Radiates millimeter radar waves forward, uses the reflected millimeter waves for detecting the presence of a vehicle ahead, the vehicle-to-vehicle distance, and the relative speed, and then transmits this information to the driving support ECU assembly.
    Driving Support ECU Assembly Determines whether a collision is unavoidable based on the information received from the millimeter wave radar sensor assembly. It then outputs a brake assist standby request signal and pre-crash brake request signal if required.
    Brake Actuator Assembly Master Cylinder Pressure Sensor Detects the master cylinder pressure and transmits a signal to the skid control ECU (brake actuator assembly).
    Pump Motor Receives an operation signal from the skid control ECU and generates hydraulic pressure for brake control.
    Skid Control ECU

    • Receives a brake assist standby request signal from the driving support ECU assembly and switches the brake assist to standby mode. When a stop light switch signal is input, it activates the brake assist.

    • Receives a pre-crash brake request signal from the driving support ECU assembly, and then applies the brakes.

    • Transmits vehicle speed signals to the driving support ECU assembly.
    Speed Sensors Detect the wheel speed of each of the 4 wheels and transmits the signals to the skid control ECU (brake actuator assembly).
    Yawrate Sensor Detects the yaw rate and lateral/longitudinal deceleration of the vehicle and transmits the signal to the driving support ECU assembly.
    Steering Sensor Detects the angle and direction of steering and transmits a signal to the driving support ECU assembly.
    Pre-crash System Cancel Switch Assembly Disables the pre-crash safety system operation when the switch is turned on. The PCS warning light illuminates to show that the pre-crash safety system operation is disabled.
    Skid Control Buzzer Assembly Sounds to warn the driver in accordance with signals from the millimeter wave radar sensor assembly.
    Stop Light Switch Assembly Detects if the brake pedal is depressed and transmits a signal to the driving support ECU assembly.
    Combination Switch Assembly VSC OFF Switch Disables the pre-crash brake and pre-crash brake assist operation when the switch is turned on. The PCS warning light illuminates to show that the pre-crash brake and pre-crash brake assist operation is disabled.
    Combination Meter Assembly PCS Warning Light

    • Flashes or illuminates to warn the driver in accordance with signals from the driving support ECU assembly.

    • Flashes when the system is malfunctioning or temporarily disabled.

    • Illuminates when the pre-crash safety system is not available due to certain reasons or when pre-crash brake and pre-crash brake assist operation are disabled using the VSC OFF switch.
    Multi-information Display Displays a warning message to inform or warn the driver of the system condition in accordance with signals from the driving support ECU assembly.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the driving support ECU assembly.
    Multi Buzzer Sounds to warn the driver in accordance with signals from the driving support ECU assembly when the system is malfunctioning.
    Absorber Control ECU* Receives an adaptive variable suspension (AVS) operation request signal from the driving support ECU assembly and operates the absorber control actuators.
    Absorber Control Actuator* Changes the damping force of the shock absorber assembly.

    *: Models with adaptive variable suspension system

  2. SYSTEM CONTROL


    1. High Possibility of Collision or Unavoidable Collision

      (1) The driving support ECU assembly determines that the possibility of a collision is high based on the signals received from the millimeter wave radar sensor assembly, steering sensor, speed sensor and yawrate sensor.
      (2) The driving support ECU assembly transmits a PCS warning display request signal to the combination meter assembly and a skid control buzzer assembly request signal to the millimeter wave radar sensor assembly.
      (3) The driving support ECU assembly outputs a pre-crash brake assist request signal to the skid control ECU (brake actuator assembly). Upon receiving this signal, the skid control ECU (brake actuator assembly) switches the brake assist to the standby condition. At this time, the skid control ECU (brake actuator assembly) activates pre-crash brake assist when the brake pedal is depressed by the driver.
      (4) The driving support ECU assembly outputs an adaptive variable suspension (AVS) system request signal to the absorber control ECU. Upon receiving this signal, the absorber control ECU controls the absorber control actuators.*
      (5) The driving support ECU assembly determines that an unavoidable collision condition exists based on the signals received from the millimeter wave radar sensor assembly, speed sensor, steering sensor and yawrate sensor.
      (6) The driving support ECU assembly outputs a pre-crash brake request signal to the skid control ECU (brake actuator assembly).
      (7) The skid control ECU (brake actuator assembly) decreases the vehicle speed by activating the brake actuator to perform a pre-crash brake operation and activates the stop light control relay to turn on the stop lights.
      (8) If no collision occurs, the brake assist will return to its normal state.

      *: Models with adaptive variable suspension system

      A001HFSE03

    2. Operating Conditions

      Operating Conditions

      • The pre-crash safety system operates when the driving support ECU assembly determines the high possibility of a collision, or an unavoidable collision with an obstacle in front of the vehicle.

      • Pre-crash safety system operation has not been disabled using the pre-crash system cancel switch assembly.

    3. The following pre-crash safety system controls are performed under the following conditions.

      Control Condition
      Pre-crash Brake

      • Vehicle speed is approximately 15 km/h (10 mph) or above.

      • Relative speed of oncoming vehicle or obstacle is approximately 15 km/h (10 mph) or above.

      • Pre-crash safety system operation has not been disabled using pre-crash system cancel switch assembly.

      • VSC OFF switch is not pressed.
      Pre-crash Brake Assist

      • Vehicle speed is approximately 30 km/h (19 mph) or above.

      • Relative speed of oncoming vehicle or obstacle is approximately 30 km/h (19 mph) or above.

      • Brake pedal is depressed.

      • Pre-crash safety system operation has not been disabled using pre-crash system cancel switch assembly.

      • VSC OFF switch is not pressed.
      AVS Control*

      • Vehicle speed is approximately 5 km/h (19 mph) or above.

      • Relative speed of oncoming vehicle or obstacle is approximately 30 km/h (19 mph) or above.

      *: Models with adaptive variable suspension system

  3. DIAGNOSIS


    1. Initial Check


      1. The driving support ECU assembly performs an initial check on the system for approximately 3 seconds after the engine switch has been turned on (IG).

    2. Monitor Function


      1. After completing the initial check, the pre-crash safety system becomes ready to operate. During this time, the driving support ECU assembly periodically monitors the system for any malfunctions.

    3. Diagnostic Trouble Code (DTC)


      1. If the driving support ECU assembly detects a malfunction in the pre-crash safety system, it stores a 5 digit Diagnostic Trouble Code (DTC) in memory.