PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SAFETY SYSTEM


    1. The pre-crash safety system automatically activates the occupant protection equipment (see below) to attempt to reduce damage due to a collision to the passengers and vehicle.

    2. This operation can be disabled by the pre-crash system cancel switch assembly.

      Tech Tips

      While the pre-crash safety system is disabled, the PCS warning indicator light on the combination meter is turned on.

  2. OUTLINE OF PRE-CRASH SAFETY SYSTEM

    Operating Condition Control Transmitting ECU Receiving ECU Part Operated
    Operates according to millimeter wave radar sensor detection Pre-crash seat belt Driving Support ECU Assembly Seat belt control ECU Front seat outer belts
    Operates according to millimeter wave radar sensor detection Pre-crash brake assist Driving Support ECU Assembly Brake booster with master cylinder assembly (skid control ECU) Brake system
    Operates when sudden braking or skidding occurs Pre-crash seat belt Brake booster with master cylinder assembly (skid control ECU) Seat belt control ECU Front seat outer belts
    Operates according to millimeter wave radar sensor detection Pre-crash brake Driving Support ECU Assembly Brake booster with master cylinder assembly (skid control ECU) Brake system

    1. When operating according to millimeter wave radar sensor detection:

      The millimeter wave radar sensor detects vehicles and other objects on the road in front of the user's vehicle. The driving support ECU assembly determines if the possibility of a collision is high of if a collision is unavoidable based on object position, speed and track information. If the driving support ECU assembly determines that the possibility of collision is high of that a collision is unavoidable, it transmits this information to the following areas using CAN communication:


      • Seat belt control ECU (initiates control of pre-crash seat belts)

      • Brake booster with master cylinder assembly (skid control ECU) (activates pre-crash brake assist system)

      • Brake booster with master cylinder assembly (skid control ECU) (activates pre-crash brake)

    2. When operating as a result of sudden braking or skidding:

      The brake booster with master cylinder assembly (skid control ECU) uses brake pressure information and other data to determine if the driver has suddenly applied the brakes or lost control of the vehicle. If so, the brake booster with master cylinder assembly (skid control ECU) sends a signal to the seat belt control ECU through CAN communication and the pre-crash seat belts operate.

  3. OUTLINE OF PRE-CRASH SEAT BELT CONTROL


    1. The pre-crash seat belts operate depending on what the millimeter wave radar sensor detects, or whether sudden braking or skidding has occurred. The pre-crash seat belts motor retracts the seat belt to enhance pretensioner effectiveness.

    2. Operating condition


      1. Refer to the millimeter wave radar sensor and sudden braking or skidding descriptions under "Outline of Pre-crash Safety System" (see above).

  4. OUTLINE OF PRE-CRASH BRAKE ASSIST CONTROL


    1. The pre-crash brake assist operates depending on what the millimeter wave radar sensor detects. The system then enters standby mode before a collision. When the driver depresses the brake pedal, brake fluid pressure is increased to improve fluid pressure response and improve the rate of deceleration.

    2. Operating condition


      1. Refer to the millimeter wave radar sensor description under "Outline of Pre-crash Safety System" (see above).

      2. When the driver depresses the brake pedal after the driving support ECU assembly determines that there is a collision is high possibility of collision:

        Brake fluid pressure is increased at the same time the driver depresses the brake pedal.

  5. OUTLINE OF PRE-CRASH BRAKE CONTROL


    1. The pre-crash brake operation is performed depending on what the millimeter wave radar sensor detects.

    2. Operating condition


      1. Refer to the millimeter wave radar sensor description under "Outline of Pre-crash Safety System" (see above).

      2. When the driving support ECU assembly determines that a collision is unavoidable, the system performs brake control (pre-crash brake operation) to reduce the vehicle speed.

        When a preceding vehicle is detected, the system advances brake control (pre-crash brake operation) activation timing in order to increase speed reduction performance.

  6. OPERATIVE CONDITION AND INOPERATIVE CONDITION OF EACH CONTROL (REVIEW)

    Tech Tips

    Each function will operate when all items marked (○) are satisfied.

    Pre-crash Seat Belt*1 Pre-crash Seat Belt*2 Pre-crash Brake Assist*2 Pre-crash Brake*2*3
    When power switch is on (IG) ○ ○ ○ ○

    No malfunctions in related components Click here

    		○ ○ ○ ○
    When front seat belt(s) is/are fastened ○ ○ - -
    Operates when the vehicle speed is 30 km/h (19 mph) or more, regardless of relative speed ○ - - -
    Operates when the vehicle speed is 5 km/h (4 mph) or more and relative speed is 30 km/h (19 mph) or more - ○ - -
    Operates when the vehicle speed is 15 km/h (10 mph) or more and relative speed is 15 km/h (10 mph) or more - - - ○
    Operates when the vehicle speed is 30 km/h (19 mph) or more and relative speed is 30 km/h (19 mph) or more - - ○ -
    When pre-crash safety system has not been disabled using the pre-crash system cancel switch assembly ○ ○ ○ ○
    When the brake pedal is depressed - - ○ -

    • *1: Operates when sudden braking or skidding is detected.

    • *2: Does not operate in the following situations.


      • When the vehicle collides with an object outside the detection range of the millimeter wave radar sensor (side collision, rear collision, etc.)

      • When the millimeter wave radar sensor cannot detect a possible collision object

    • *3: Except Taiwan

    • ○: Main basis for operation

    • -: Not main basis for operation

  7. CASES OF UNNECESSARY PRE-CRASH SAFETY SYSTEM OPERATION


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

      A0006Y4E01
      Text in Illustration
      *a There are objects on the side of the road at the beginning of a curve (a guardrail, street lamp, billboard, etc.). *b Passing an oncoming vehicle on a curve.
      *c There is an oncoming vehicle when making a left turn. *d Crossing a narrow metal bridge.
      *e There are metal objects on the road. *f Approaching a leading vehicle suddenly.
      *g Electrical toll collection gate (React to bar.) *h Crossing an overpass, traffic sign, signboard
      *i The vehicle height drastically changes (nose-up, nose-down). *j Misalignment of millimeter wave radar sensor. (reinstallation, collision, etc)
      *k There is a billboard or sign at the top of an incline. *l There are metal objects at the bottom of a decline (a metal plate covering road construction, a mesh drain cover, a manhole, etc.)
      *m Roughness in road surface. - -

      Tech Tips


      • The pre-crash safety system will not activate when approaching safety cones or other plastic objects as they cannot be detected by the millimeter wave radar sensor.

      • The pre-crash safety system may or may not activate when the millimeter wave radar sensor detects the following objects: people, bicycles, motorcycles, trees, animals and snow fences, etc.

      • Detection performance may deteriorate in the following conditions.


        • On a tight curve or bumpy road

        • Something or someone suddenly emerges in the direction of travel of the driver's vehicle at a place such as an intersection

        • Another vehicle suddenly cuts in traveling direction of driver's own vehicle

        • In severe weather such as heavy rain, fog , snow or a sand storm

        • Vehicle is skidding sideways while electronically controlled brake system is not operating

        • Vehicle height changes significantly (front of vehicle inclined either upward or downward)

        • Millimeter wave radar sensor is misaligned (due to reinstallation or collision)

          Object Type Example
          Objects that cannot be detected Plastic items (safety cones)
          Objects that cannot be detected in a stable manner People, bicycles, motorcycles, trees, animals, snow fences, etc.