PRE-CRASH SAFETY SYSTEM SYSTEM DESCRIPTION


  1. PRE-CRASH SAFETY SYSTEM DESCRIPTION


    1. The pre-crash safety system determines the possibility of a collision according to information such as the position of the obstacle and its relative speed, and provides optimal control to avoid the collision and control to reduce the impact during the collision via warnings, brake assist and automatic braking.

  2. FUNCTION OF COMPONENTS

    Component Function
    Pre-crash Safety City Sensor

    • Acquires information about the preceding vehicle from a monocular camera and laser sensor to perform pre-crash safety system control.

    • PCS warning light (PCS OFF indicator) and pre-crash safety buzzer sounding signals to the combination meter assembly based on pre-crash control information.

    • Sounds the buzzer during warning operation.

    • Operates the pre-crash safety city heater to remove condensation from the part of the windshield in front of the pre-crash safety city sensor.*2
    Pre-crash System Cancel Switch Assembly Stops and starts the pre-crash safety system and changes the warning timing.
    Pre-crash Safety City Buzzer*1 Sounds according to signals from the pre-crash safety city sensor.
    Combination Meter Assembly

    • Displays the pre-crash safety system control status (ON/OFF) and warning timing.

    • During a system malfunction, warns the driver by illuminating the PCS warning light (PCS OFF indicator) and sounding the pre-crash safety buzzer.

    • Sounds to warn the driver in accordance with signals from the pre-crash safety city sensor when the system are operating or malfunctioning.
    ECM

    • Detects the shift position signal and accelerator opening angle and sends that information to the pre-crash safety city sensor.

    • Performs engine output control based on information from the pre-crash safety city sensor.
    Brake Actuator Assembly (Skid Control ECU)

    • Sends information such as the vehicle speed signal, stop light switch signal and brake control hydraulic pressure to the pre-crash safety city sensor.

    • Performs brake hydraulic pressure and emergency brake signal control based on information from the pre-crash safety city sensor.
    Spiral with Sensor Cable Sub-assembly (Steering Angle Sensor) Detects the steering angle and steering direction.
    Airbag ECU Assembly (Yaw Rate Sensor) Airbag ECU Assembly (Yaw Rate Sensor)
    Main Body ECU (Multiplex Network Body ECU) Sends destination information to the pre-crash safety city sensor.
    VSC OFF Switch Disables the pre-crash brake and pre-crash brake assist operation when the switch is turned on.

    • *1: w/o Pre-crash Safety City Heater

    • *2: w/ Pre-crash Safety City Heater

  3. OUTLINE OF PRE-CRASH DETECTION


    1. Collision detection


      1. The system determines in advance the possibility of a collision and whether the collision can be avoided based on road surface conditions and the position and speed of the preceding vehicle according to information about the preceding vehicle from the pre-crash safety city sensor.

        Tech Tips

        For details about the system, see "OUTLINE OF PRE-CRASH SAFETY SYSTEM CONTROL" and the function descriptions.

      2. Component

        Component Detection Content
        Pre-crash safety city sensor Obstacle in front (vehicle)

  4. OUTLINE OF PRE-CRASH SAFETY SYSTEM CONTROL

    Control Condition Start of Control Sender ECU Receiver ECU Operated Parts
    Pre-crash warning Collision is possible Pre-crash safety city sensor Combination meter assembly

    • Combination meter assembly (PCS warning light (PCS OFF indicator))

    • Pre-crash safety buzzer (warning sound)*1

    • Combination meter assembly (warning sound)*2
    Pre-crash brake assist Collision is highly possible Pre-crash safety city sensor

    • Combination meter assembly

    • Brake booster with master cylinder assembly (skid control ECU)

    • Combination meter assembly (PCS warning light (PCS OFF indicator))

    • Pre-crash safety buzzer (warning sound)*1

    • Combination meter assembly (warning sound)*2

    • Brake booster with master cylinder assembly (skid control ECU)
    Pre-crash brake Collision is unavoidable Pre-crash safety city sensor

    • Combination meter assembly

    • Brake booster with master cylinder assembly (skid control ECU)

    • Combination meter assembly (PCS warning light (PCS OFF indicator))

    • Pre-crash safety buzzer (warning sound)*1

    • Combination meter assembly (warning sound)*2

    • Brake booster with master cylinder assembly (skid control ECU)

    • *1: w/o Pre-crash Safety City Heater

    • *2: w/ Pre-crash Safety City Heater

  5. PRE-CRASH ALARM CONTROL


    1. When the system determines that there is a risk of colliding with an obstacle in front of the vehicle, a message on the (PCS warning light (PCS OFF indicator)) and a buzzer is used to warn the driver to avoid the collision.

  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 enters standby status and the hydraulic brake pressure is increased to improve braking effectiveness when the driver depresses the brake pedal.

  7. PRE-CRASH BRAKE CONTROL


    1. When the system determines that a collision with an obstacle in front of the vehicle is unavoidable, the brakes are operated to reduce the collision speed and reduce the impact during the collision.

      Note

      When the system detects that the driver is attempting to cancel operation of the system by performing operations such as the following, pre-crash brake control is canceled.


      • Accelerator pedal is forcefully depressed

      • Steering wheel is operated quickly to avoid a collision

    2. Turning the VSC OFF switch on disables pre-crash brake assist control and pre-crash brake control.

      Tech Tips

      After pressing the switch, the PCS OFF warning light in the combination meter assembly will illuminate.

  8. PRE-CRASH SAFETY SYSTEM (PCS) OPERATION CONDITIONS


    1. The pre-crash alarm control, pre-crash brake assist control and pre-crash brake control can operate if all of the following conditions are met:


      • Pre-crash safety system is on

      • VSC system is not disabled

      • PCS warning light in combination meter assembly does not blink

    2. If the following conditions are met, the pre-crash alarm control will operate:


      • Vehicle speed is between approximately 15 km/h (10 mph) and 140 km/h (87 mph)

      • Relative speed is approximately 15 km/h (10 mph) or more

    3. If the following conditions are met, the pre-crash brake assist control will operate:


      • Vehicle speed is between approximately 30 km/h (19 mph) and 80 km/h (50 mph)

      • Relative speed is approximately 30 km/h (10 mph) or more

    4. If the following conditions are met, the pre-crash brake control will operate:


      • Vehicle speed is between approximately 10 km/h (6 mph) and 80 km/h (50 mph)

      • Relative speed is approximately 10 km/h (6 mph) or more

  9. PRECAUTION FOR PRE-CRASH SAFETY CITY SENSOR


    1. When the following vehicle conditions are detected, the pre-crash safety city sensor determines that a collision is unavoidable and pre-crash control is performed, but this is not a malfunction.

      A004AMHE01
      Text in Illustration
      *A for RHD *B for LHD
      *a There are objects on the side of the road at the beginning of a curve (a guardrail, street light, billboard, etc.). *b Passing an oncoming vehicle on a curve.
      *c When passing an oncoming vehicle while making a left turn (for LHD) or right turn (for RHD). *d Passing through an area which contains an obstacle that covers the vehicle (such as a hanging curtain).
      *e There are metal objects, bumps and protrusions on the road (a metal plate covering road construction, a mesh drain cover, a manhole, etc.). *f Suddenly approaching a preceding vehicle.
      *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 Axis misalignment of pre-crash safety city 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 Snow, water, etc., is kicked up by the preceding vehicle. *n Passing through an area which contains heavy fog or smoke.
      *o The vehicle is stopped with the front extremely close to an obstacle (wall, vehicle, etc.). *p Passing extremely close to the side of an obstacle (stopped vehicle, guardrail, etc.).

      Tech Tips


      • The detection performance of the monocular camera sensor may deteriorate under the following conditions.


        • The headlights are not illuminated when the surrounding area is dark, such as inside a tunnel or at night.

        • A strong light from directly ahead of the vehicle strikes the lens (light from the headlights of an oncoming vehicle, the sun, etc.).

        • The temperature of the sensor is extremely high, such as after the vehicle is parked in hot weather.

      • The following environments and vehicle conditions may cause the detection performance to deteriorate.


        • On a steep curve or undulating 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.

        • The vehicle is skidding sideways.

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

        • The front windshield is dirty.

        • An obstacle is between the vehicle and a light source.

        • The preceding vehicle is one which does not easily reflect laser waves (the vehicle is low, small, dirty, etc.).

        • When the sensor is misaligned due to a strong impact being applied to the sensor, etc.

  10. PRE-CRASH SAFETY SYSTEM AUTOMATIC CANCELLATION


    1. When a system malfunction is detected and the sensor cannot detect vehicles, system operation cancels automatically.

      Tech Tips

      When the system malfunctions or is temporarily disabled, the PCS warning light (PCS OFF indicator) blinks.

  11. OUTLINE OF PRE-CRASH SAFETY CITY HEATER (w/ Pre-crash City Heater)


    1. The pre-crash safety city heater can operate if all of the following conditions are met:


      • No pre-crash safety system DTCs are stored

      • Engine running

    2. If either of the following conditions are met, the pre-crash safety city heater will operate:


      • Ambient temperature (detected by air conditioning system) is 5 °C (41 °F) or lower

      • Vehicle is being driven when ambient temperature is 5 to 20 °C (41 to 68 °F) and area of windshield in front of pre-crash safety city sensor begins to fog (blockage of pre-crash safety city sensor detected)

    3. If the following condition is met, the pre-crash safety city heater will stop operating:


      • 30 minutes have elapsed since pre-crash safety city heater operation began