PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SAFETY SYSTEM DESCRIPTION


    1. The pre-crash safety system detects vehicles and obstacles in front of the vehicle and performs the following: 1) optimally uses system controls to avoid crashes and 2) uses system controls to reduce impact during a crash.

  2. PRE-CRASH DETECTION OUTLINE


    1. Front crash detection


      1. The driving support ECU receives information about vehicles and obstacles in front of the vehicle from the millimeter wave radar sensor. Then, based on the vehicle speed, road conditions and obstacle location, the driving support ECU determines, in advance, the risk of a crash and if a crash is unavoidable.

    2. Sudden braking detection


      1. The skid control ECU activates the pre-crash seat belts when it detects sudden braking. Sudden braking is determined based on brake fluid pressure and other information from the master cylinder pressure sensor.

    3. Vehicle control impossible judgment


      1. The pre-crash seat belts are activated when it is determined that there is a high probability that the vehicle cannot be controlled. The judgment is based on vehicle stability information from the yaw rate sensor and steering angle sensor.

  3. PRE-CRASH SAFETY SYSTEM CONTROL DESCRIPTION

    Operation Condition Control Sender ECU Receiver ECU Part Operated
    Front crash detected Crash is possible Pre-crash alarm Driving support ECU

    • Skid control ECU

    • Combination meter

    • Skid control buzzer

    • Combination meter
    Crash is unavoidable Pre-crash seat belts Driving support ECU Seat belt control ECU Front seat outer belts

    1. Crash is possible

    2. Crash is unavoidable

    • Pre-crash brake assist

    • Pre-crash brake

    		 Driving support ECU Skid control ECU Brake assist system
    Sudden braking detected Pre-crash seat belts Skid control ECU Seat belt control ECU Front seat outer belts
    Vehicle control impossible judgment Pre-crash seat belts Skid control ECU Seat belt control ECU Front seat outer belts

  4. PRE-CRASH ALARM CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, the multi-information display and warning buzzer are used to warn the driver and help with crash avoidance.

  5. PRE-CRASH SEAT BELT CONTROL


    1. If the pre-crash sensor detects that a collision is unavoidable, the pre-crash safety system will retract the seat belt, thus enhancing the effectiveness of the seat belt pretensioner in a crash. The same will happen if the driver makes an emergency braking or loses control of the vehicle.

  6. PRE-CRASH BRAKE ASSIST CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, brake assist is set to standby mode. Then, when the driver depresses the brake pedal, the hydraulic brake pressure is increased to improve braking effectiveness.

  7. PRE-CRASH BRAKE CONTROL


    1. When the system determines that a crash with an obstacle is unavoidable, the system performs brake control to reduce the vehicle speed.

  8. PRE-CRASH BRAKE CANCEL SWITCH


    1. When the pre-crash brake cancel switch in the No. 1 instrument panel under cover is turned on, the pre-crash alarm and pre-crash brake do not operate.

      Tech Tips

      While the pre-crash brake cancel switch is on, the PCS indicator light in the combination meter illuminates.

  9. PRE-CRASH SAFETY SYSTEM OPERATING CONDITION

    Vehicle Condition Pre-crash Alarm Pre-crash Seat Belt (Linked with Understeer or Oversteer Tendency Operation and Sudden Brake Operation) Pre-crash Seat Belt (Linked with Radar) Pre-crash Brake Assist Pre-crash Brake Control
    When ignition switch is off or ACC X X X X X
    When warning message is displayed on multi-information display *1 *1 *1 *1 *1
    When seat belt(s) are fastened ○ ○ ○ ○ ○
    When vehicle speed is 30 km/h (18 mph) or more, regardless of relative speed X ○ X X X
    When vehicle speed is 15 km/h (9 mph) or more and relative speed is 15 km/h (9 mph) X X X X ○
    When vehicle speed is 5 km/h (3 mph) or more and relative speed is 30 km/h (18 mph) X X ○ X X
    When vehicle collides with object outside detection range of millimeter wave radar sensor (side collision, rear-end collision, etc.) X *2 X X X
    When millimeter wave radar sensor cannot detect possible collision object X *2 X X X
    When vehicle speed is 30 km/h (18 mph) or more, and relative speed of other vehicle is 30 km/h (18 mph) or more X X X ○ X

    ○: Operation

    X: No operation

    *1: Inoperative functions are different depending on malfunction areas

    *2: Pre-crash seat belts may operate when brakes are suddenly applied

  10. PRECAUTION FOR MILLIMETER WAVE RADAR SENSOR


    1. When the millimeter wave radar sensor detects an object in front of the vehicle under the conditions described below, the driving support ECU may determine that a collision is unavoidable and activate the pre-crash safety system. However, this is not abnormal.

      A004N52E05

      Tech Tips


      • The pre-crash safety system is not activated by safety cones and other plastic objects which cannot be detected by the millimeter wave radar sensor.

      • The pre-crash safety system may or may not be activated by the following objects which cannot always be detected by the millimeter wave radar sensor: people, bicycles, motorcycles, trees, animals, snow fences, etc.

      Object Type Example
      Object that cannot be detected Safety cones, plastic items
      Object that cannot always be detected People, bicycles, motorcycles, trees, animals, snow fences