PRE-CRASH SAFETY SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Item Function

    Pre-crash Safety City Sensor


    • Monocular Camera Sensor

    • Laser Sensor

    • Pre-crash Safety City Sensor ECU

    • Receives information from the monocular camera sensor and laser sensor regarding vehicles ahead, and performs pre-crash safety system control.

    • When performing pre-crash safety system control, it also sends request signals to the combination meter assembly to display applicable messages and sound the buzzer.

    • When pre-crash brake or pre-crash brake assist are operating, it sends signals to the skid control ECU requesting vehicle speed reduction.

    • 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

    Brake Actuator Assembly


    • Skid Control ECU

    • Pump Motor

    • Master Cylinder Pressure Sensor

    • Based on the pre-crash safety city sensor signal, sends control signals to the brake actuator to operate the brakes.

    • Sends vehicle speed signal, stop light switch signal and master cylinder pressure signal to the pre-crash safety city sensor.

    • Detects brake control signals and sends signals to the stop light switch assembly*3 or STP relay*4.

    • Receives an operation signal from the skid control ECU and generates hydraulic pressure for brake control.

    • Detects the master cylinder pressure and transmits a signal to the skid control ECU.

    Combination Meter Assembly


    • PCS Warning Light

    • PCS Activation Indicator

    • Multi-information Display

    • Buzzer

    • During warning operation, flashes the PCS activation indicator to warn the driver.

    • When the pre-crash safety system is OFF, the PCS warning light illuminates.

    • When the pre-crash safety system is not available due to certain reasons, the PCS warning light illuminates.*2

    • During system malfunction, flashes the PCS warning light and sounds the buzzer to warn the driver.

    • Based on pre-crash system cancel switch assembly operation, displays pre-crash safety system ON/OFF and warning timing.
    ECM

    • Sends the accelerator pedal opening angle signal and shift position signal*5 or reverse position signal*1*6 to the pre-crash safety city sensor.

    • Controls engine output based on the signal from the pre-crash safety city sensor.

    Airbag Sensor Assembly


    • Yaw Rate Sensor

    • Acceleration Sensor

    		 Detects the yaw rate (rotational movement) and front/back/left/right acceleration of the vehicle body, and sends the signal to the pre-crash safety city sensor.

    Spiral Cable with Sensor Sub-assembly


    • Steering Angle Sensor

    		 Detects the steering and direction, and sends the signal to the pre-crash safety city sensor.
    Pre-crash Safety City Buzzer*1 Sounds during warning operation to warn the driver.
    Pre-crash System Cancel Switch Assembly By operating the switch, the pre-crash safety system can be turned ON/OFF and the warning timing can be changed.
    VSC OFF Switch When the VSC OFF switch is operated to turn the brake system to VSC OFF mode, pre-crash brake and pre-crash brake assist operation is turned OFF (only the pre-crash warning function can operate).
    Speed Sensors Detect the wheel speeds, and send the signals to the skid control ECU.
    Stop Light Switch Assembly

    • Detects that the brake pedal has been depressed, and sends the signal to the skid control ECU.

    • Illuminates the stop light based on signals from the skid control ECU.*3

    No. 5 Relay Block*4


    • STP Relay

    		 Illuminates the stop light based on signals from the skid control ECU.
    Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression amount and sends the signal to the ECM.
    Thermistor Assembly*2 Detects ambient temperature and outputs it to the combination meter assembly.
    Pre-crash Safety City Heater*2 Heats the heater pattern area in accordance with the signals from the pre-crash safety city sensor.
    Park/Neutral Position Switch Assembly*5 Detects the shift position and sends the signal to the ECM.
    Back-up Light Switch Assembly*1*6 Detects the reverse position and sends the signal to the ECM.

    *1: Models without pre-crash safety city heater

    *2: Models with pre-crash safety city heater

    *3: Models with LED type stop light

    *4: Models without LED type stop light

    *5: Models with CVT

    *6: Models with manual transaxle

  2. FUNCTION


    1. The pre-crash safety system uses the monocular camera sensor and laser sensor inside the pre-crash safety city sensor to determine if there is a risk of this vehicle colliding with the preceding vehicle.

    2. When the probability of a collision is high, the pre-crash safety system sends a warning via the meter display and buzzer, and performs brake assist control. Additionally, when the probability of a collision is extremely high, the system performs brake control in order to help reduce the impact force if a collision occurs.

    3. During brake control by the pre-crash safety system, the skid control ECU illuminates the stop light in order to inform any following vehicles that this vehicle is braking.

      A0044VME02
      Text in Illustration
      *a This Vehicle *b Probability of collision extremely high
      *c Preceding Vehicle *d The illustrations shown are examples only.
      A0044Y3 Laser Sensor Detection Area A0044SQ Monocular Camera Sensor Image Recognition Area

  3. OPERATING CONDITION


    1. The pre-crash safety system is enabled and determines that the possibility of a frontal collision with a vehicle is high.

      Pre-crash Safety System Operating Conditions
      Pre-crash Warning

      • Vehicle speed is approximately 15 to 140 km/h (10 to 86 mph).

      • The relative speed between your vehicle and the vehicle ahead is greater than approximately 15 km/h (10 mph).
      Pre-crash Brake Assist

      • Vehicle speed is approximately 30 to 80 km/h (19 to 49 mph).

      • The relative speed between your vehicle and the vehicle ahead is greater than approximately 30 km/h (19 mph).

      • The brake pedal is being depressed.
      Pre-crash Brake

      • Vehicle speed is approximately 10 to 80 km/h (7 to 49 mph).

      • The relative speed between your vehicle and the vehicle ahead is greater than approximately 10 km/h (7 mph).

      Tech Tips

      In case of the following, the system will not operate:


      • Steering Sensor zero point calibration has not been completed

      • If VSC is disabled (only the pre-crash warning function will be operational)

      • If the PCS warning light is flashing or illuminated

      • If the shift position is in R

    2. If either of the following situations occur while the pre-crash brake function is operating, it will be canceled:


      • The accelerator pedal is depressed strongly

      • The steering wheel is turned sharply or abruptly

    3. If the vehicle is stopped by the operation of the pre-crash brake function, the operation of the pre-crash brake function will be canceled after the vehicle has been stopped for approximately 2 seconds.

    4. When the driver is depressing the brake pedal, the system judges that the driver is preparing to avoid a collision, so the system may delay the pre-crash brake activation timing.

    5. During the following, the driver operations takes precedence and the system may not operate:


      • The accelerator pedal is depressed strongly

      • The steering wheel is turned sharply or abruptly

    6. In some situations such as the following, the system may determine that there is a possibility of a frontal collision and operate:


      • When passing a vehicle in an oncoming lane that is stopped to make a left/right turn

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      • When passing an oncoming vehicle while making a left/right turn

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      • When driving on a road where relative location to vehicle ahead in an adjacent lane may change, such as on a winding road

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      • When rapidly closing on a preceding vehicle

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      • If the front of the vehicle is raised or lowered, such as when the road surface is uneven or undulating

      • When passing extremely close to a vehicle or structural object

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      • When there is a vehicle or object by the roadside at the entrance of a curve

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      • When driving on a narrow path surrounded by a structure, such as in a tunnel or on an iron bridge

      • When there is a reflective object (manhole cover, steel plate, etc.), steps, dip, or a protrusion on the road surface or roadside

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      • When passing through a place with a low structure above the road (low ceiling, traffic sign, etc.)

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      • When there is a structural object (overpass, traffic sign, billboard, street light, etc.) at the top of an uphill road

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      • When rapidly closing on an electric toll gate barrier, parking area barrier, or other barrier that opens and closes

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      • When using an automatic car wash

      • When approaching a low hanging object that may contact the vehicle, such as a banner, tree branches or thick grass

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      • When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead

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      • When driving through steam or smoke

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      • When there are patterns or paint on the road or a wall that may be mistaken for a vehicle

      • When the front part of the vehicle is raised or lowered

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      • When the pre-crash safety city sensor is misaligned due to a strong impact being applied to the pre-crash safety city sensor, etc.

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      • When the vehicle is being parked in a place where there is a low hanging object at the height of the pre-crash safety city sensor

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      • When the windshield glass is covered with raindrops, etc.

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    7. In some situations such as the following, a vehicle may not be detected by the pre-crash safety city sensor, preventing the system from operating properly:


      • If an oncoming vehicle is approaching your vehicle

      • When approaching the side or front of a vehicle

      • If a preceding vehicle has a small rear end, such as an unloaded truck

      • If a preceding vehicle has a low rear end, such as a low bed trailer

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      • If a vehicle ahead is carrying a load which protrudes past its rear bumper

      • If a vehicle ahead has extremely high ground clearance

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      • If a vehicle ahead is irregularly shaped, such as a tractor or side car

      • If the sun or other light is shining directly on a vehicle ahead

      • If a vehicle cuts in front of your vehicle or emerges from beside a vehicle

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      • If a vehicle ahead makes an abrupt maneuver (such as sudden swerving, acceleration or deceleration)

      • When suddenly cutting behind a preceding vehicle

      • When a vehicle ahead is not directly in front of your vehicle

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      • When driving in inclement weather such as heavy rain, fog, snow or a sand storm

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      • When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead

      • When driving through steam or smoke that may obscure vehicles ahead

      • When driving in a place where the surrounding brightness changes suddenly, such as at the entrance or exit of a tunnel

      • When a very bright light, such as the sun or the headlights of oncoming traffic, shines directly into the pre-crash safety city sensor

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      • When the surrounding area is dim, such as at dawn or dusk, or while at night or in a tunnel

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      • While driving on a curve and for a certain amount of time after driving on a curve

      • If your vehicle is skidding

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      • When the front part of the vehicle is raised or lowered

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      • If the wheels are misaligned

      • If a wiper blade is blocking the pre-crash safety city sensor

      • The vehicle is wobbling

      • The vehicle is being driven at extremely high speeds

      • When driving on roads with sharp bends or uneven surfaces

      • When a preceding vehicle is a poor reflector of laser

      • When the pre-crash safety city sensor is misaligned due to a strong impact being applied to the pre-crash safety city sensor, etc.

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    8. In some situations such as the following, sufficient braking force may not be obtained, preventing the system from performing properly:


      • If the braking functions cannot operate to their full extent, such as when the brake parts are extremely cold, extremely hot, or wet

      • If the vehicle is not properly maintained (brakes or tires are excessively worn, improper tire inflation pressure, etc.)

      • When the vehicle is being driven on a gravel road or other slippery surface

    9. If the PCS warning light flashes or illuminates, the pre-crash safety system may be temporarily unavailable or there may be a malfunction in the system.


      1. In the following situations, the warning light will turn off and the system will become operational when normal operating conditions return:


        • When the area around the pre-crash safety city sensor is hot, such as in the sun

        • When the windshield glass is fogged up, or covered with condensation or ice

        • When the pre-crash safety city sensor or the area around the sensor is cold, such as in an extremely cold environment

        • If the area in front of the pre-crash safety city sensor is obstructed, such as when the hood is open

      2. If the PCS warning light continues to flash, the system may be malfunctioning.

    10. If VSC is disabled, the pre-crash brake assist and pre-crash brake functions are also disabled. However, the pre-crash warning function will still operate.

  4. SYSTEM CONTROL


    1. The pre-crash safety city sensor sends and receives signals to and from various ECUs, sensors and switches to perform pre-crash safety system control.

      Pre-crash Safety System Control List
      Control Function
      Pre-crash Brake

      • When the system determines that there is a high possibility of a collision, the PCS activation indicator in the combination meter assembly flashes and the buzzer sounds to warn the driver.

      • When the system determines that there is an extremely high probability of a collision, the brake is applied to reduce vehicle speed even if the driver has not depressed the brake pedal.
      Pre-crash Brake Assist When the system determines that there is a high probability of a collision, brake hydraulic pressure assistance is performed, improving brake effectiveness when the brake pedal is depressed. Also, if the brake pedal is depressed before the system determines there is a high possibility of a collision, once the determination is made, brake hydraulic pressure assistance is immediately performed.

    2. Pre-crash Brake


      1. When the pre-crash safety city sensor detects an object such as a vehicle or road structure in front of the vehicle and determines that the probability of a collision is high, the PCS activation indicator in the combination meter assembly flashes and the buzzer sounds to warn the driver.

      2. When the system determines that there is an extremely high probability of a collision, pre-crash brake control activates.

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    3. Pre-crash Brake Assist


      1. While the pre-crash safety city sensor has determined that there is a high probability of a collision, brake hydraulic pressure assistance is performed when the driver depresses the brake pedal. Also, the amount of brake hydraulic pressure assistance increases further when the system determines that there is an extremely high probability of a collision.

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      2. When the driver begins to depress the brake pedal before the system determines that there is a high probability of a collision, once the determination is then made, brake hydraulic pressure assistance is immediately performed. This hydraulic pressure assistance is also applied in response to the amount the brake pedal was depressed before the start of assistance.

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  5. CONSTRUCTION


    1. Pre-crash Safety City Sensor


      1. The pre-crash safety city sensor is installed on the inside of the windshield glass, at the top center. It uses its built-in monocular camera sensor to acquire a video of the area in front of the vehicle, uses its built-in laser sensor to detect other vehicles in front of this vehicle, and uses both detection results to determine whether there is a preceding vehicle and how far away it is, enhancing high recognition performance and reliability.

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        Text in Illustration
        *1

        Pre-crash City Sensor


        • Pre-crash City Sensor ECU

        		 - -
        *a Monocular Camera Sensor *b Laser Sensor Receiver
        *c Laser Sensor Emitter *d Laser Sensor Detection Area
        *e Monocular Camera Sensor Image Processing Area - -

    2. Pre-crash Safety City Heater


      1. The pre-crash safety city heater, which is installed between the pre-crash safety city sensor and windshield glass, is heated in the heater pattern area according to signals from the pre-crash safety city sensor in order to prevent the windshield glass on the front of the pre-crash safety city sensor from fogging, and also to remove fog buildup.

      2. 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

      3. If either or 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)

      4. 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

  6. OPERATION


    1. Pre-crash Safety System Display


      1. The pre-crash safety system uses the PCS warning light, PCS activation indicator and buzzer inside the combination meter assembly to display warnings and operating status information.

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        Text in Illustration
        *1 Combination Meter Assembly - -
        *a Multi-information Display *b PCS Warning Light
        *c PCS Activation Indicator - -

    2. Pre-crash Safety System Operating Status Display


      1. When the pre-crash safety city sensor, which controls the pre-crash safety system, judges that the possibility of a collision is high, it sends a display request signal to the combination meter, causing the PCS activation indicator to blink and the buzzer to sound.

        Multi-information Display PCS Warning Light PCS Activation Indicator Buzzer
        - - Flashes Sounds Intermittently

    3. Indicator Display when Pre-crash Safety System is OFF


      1. Operating the pre-crash system cancel switch assembly allows the pre-crash safety system to be turned ON and OFF. When the system is turned OFF, the PCS warning light illuminates.

        Pre-crash Safety System Multi-information Display PCS Warning Light PCS Activation Indicator Buzzer
        ON - - - -
        OFF PCS OFF* Illuminates - -

        Tech Tips

        *: Displayed for approximately 6 seconds

      2. When VSC operation has been stopped by VSC OFF switch operation, the PCS warning light and VSC OFF indicator light illuminate.

        Multi-information Display PCS Warning Light PCS Activation Indicator VSC OFF Indicator Light
        - Illuminates - Illuminates

    4. Pre-crash Safety System Warning Display


      1. When the pre-crash safety city sensor detects a system malfunction, it sends a warning display request signal to the combination meter assembly, which flashes or illuminates the PCS warning light. If the malfunction is judged to be a system failure, the buzzer sounds.

        Displayed Status Possible Conditions PCS Warning Light Buzzer
        System Failure System Failure Flashes Sounds once
        System Voltage Abnormal Auxiliary battery voltage has decreased, etc. Flashes or Illuminates -
        Pre-crash Safety City Sensor Temperature Abnormal Operating temperature range of pre-crash safety city sensor exceeded Flashes or Illuminates -
        Pre-crash Safety City Sensor Dirty Windshield glass is dirty, frosted or fogged up Flashes or Illuminates -

    5. Pre-crash System Cancel Switch Assembly


      1. A pre-crash system cancel switch assembly is provided to turn the pre-crash safety system ON/OFF and switch between different warning timings.

      2. When the pre-crash safety system is ON, briefly pressing the pre-crash system cancel switch assembly displays the warning timing. While the warning timing is being displayed, each additional press of the pre-crash system cancel switch assembly changes the warning timing displayed on the multi-information display in the order far-middle-near. This enables the pre-crash safety system to be switched between 3 levels of sensitivity.

      3. When the pre-crash safety system is ON, pressing and holding the pre-crash system cancel switch assembly for approximately 3 seconds allows the pre-crash safety system to be cancelled. At this time, in the combination meter assembly the PCS warning light illuminates and "PCS OFF" is displayed on the multi-information display. Also, while the pre-crash safety system is cancelled, briefly pressing the pre-crash system cancel switch assembly can be turned ON again.

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