PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SYSTEM


    1. The pre-crash system optimizes and activates occupant protection equipment (see below) to attempt to reduce damage due to a collision.

    2. The operation of this system can be disabled by pressing and holding the pre-crash system cancel switch assembly.

      Tech Tips

      When the pre-crash system is disabled, a warning message is displayed on the multi-information display for 6 seconds and the PCS warning indicator will be illuminated.

  2. OUTLINE OF PRE-CRASH SYSTEM

    Operating Condition Control Transmitting ECU Receiving ECU Part Operated
    Collision is unavoidable Pre-crash alarm Driving Support ECU Assembly

    • Combination meter sub-assembly (warning message)

    • Millimeter wave radar sensor assembly (warning message)

    • Combination meter sub-assembly (warning message)

    • Skid control buzzer assembly (warning buzzer)
    Possibility of a collision is high Pre-crash brake assist Driving Support ECU Assembly Brake booster with master cylinder (skid control ECU) Brake assist system
    Collision is unavoidable Pre-crash brake Driving Support ECU Assembly Brake booster with master cylinder (skid control ECU) Brake system

    1. When operating according to 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 a collision is unavoidable based on object position, speed and track information. If the Driving Support ECU Assembly determines that a collision is unavoidable, it transmits this information to the following areas using CAN communication:


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

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

    2. When operating as a result of sudden braking:

      The brake booster with master cylinder (skid control ECU) uses brake pressure information and other data to determine if the driver has suddenly applied the brakes.

  3. OUTLINE OF PRE-CRASH ALARM


    1. When the system determines that there is a high possibility 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 collision avoidance.

  4. OUTLINE OF PRE-CRASH BRAKE ASSIST CONTROL


    1. The pre-crash brake assist operates depending on what the 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. Operative condition


      1. Refer to the sensor description under "Outline of Pre-Crash System" (see above).

      2. When the driver depresses the brake pedal after the Driving Support ECU Assembly determines that a collision is high possibility:

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

      3. When the driver depresses the brake pedal before the Driving Support ECU Assembly determines that a collision is unavoidable:

        Brake fluid pressure is increased at the same time that the Driving Support ECU Assembly receives a pre-crash sensor signal (indicating that other vehicles or objects are in front of the vehicle).

  5. OUTLINE OF PRE-CRASH BRAKE CONTROL


    1. The pre-crash brake operation is performed depending on what the sensor detects. This system can be canceled by the pre-crash system cancel switch assembly.

      Tech Tips

      While the pre-crash brake operation is canceled, the PCS indicator light on the combination meter turns on.

    2. Operating condition


      1. Refer to the sensor description under "Outline of Pre-Crash 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.

  6. PRE-CRASH SYSTEM SENSITIVITY SWITCHING FUNCTION


    1. Each time the switch is pressed, the sensitivity display on the multi-information display changes between "Far", "Middle" and "Near", and the sensitivity of the pre-crash system is changed to the displayed level.

      Tech Tips


      • The sensitivity display on the multi-information display is displayed for 6 seconds.

      • "Middle" is the default setting.

      A005D5IE01
      Text in Illustration
      *a Far *b Middle
      *c Near - -

  7. PRE-CRASH SYSTEM CANCEL FUNCTION


    1. When the switch is pressed and held for 3 seconds, the pre-crash system is canceled.

      Tech Tips

      When the pre-crash system is canceled, a warning message will be displayed on the multi-information display and the PCS warning indicator will be illuminated.

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

    Tech Tips

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

    Pre-Crash Alarm Pre-Crash Brake Assist* Pre-Crash Brake*
    When power switch is on (IG) ○ ○ ○

    No problem in related components Click here

    		○ ○ ○
    Operates when the vehicle speed is 15 km/h (10 mph) or more and relative speed is 10 km/h (7 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 system operation has not been disabled using the pre-crash system cancel switch assembly ○ ○ ○
    When the brake pedal is depressed - ○ -

    • *: 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

    • ○: Main basis for operation

    • -: Not main basis for operation

  9. CASES OF UNNECESSARY PRE-CRASH SYSTEM OPERATION


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

      A005CC0E02
      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 Approaching an electrical toll collection gate (reacts 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 assembly (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. *n When passing through a tunnel.
      *o The front of the vehicle is inclined (due to towing a trailer or another vehicle, or carrying a heavy load). - -

      Tech Tips


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

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

      • Detection performance may deteriorate under 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 the traveling direction of the driver's own vehicle

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

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

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

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

        • An obstacle suddenly appears in front of the vehicle due to the steering wheel being turned sharply, etc.

          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.