PRE-COLLISION SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Item Function
    Millimeter Wave Radar Sensor Assembly Radiates millimeter wave radar forward, uses the reflected millimeter waves for detecting the presence of a vehicle ahead, the vehicle-to-vehicle distance, and the relative speed, and then transmits this information to the driving support ECU assembly.
    Forward Recognition Camera Captures images of the area in front of the vehicle and processes them to detect vehicles and sends information to the driving support ECU assembly.
    Camera Heater (Forward Recognition with Heater Hood Sub-assembly) Heats the sheet heater in accordance with the signals from the forward recognition camera.
    Driving Support ECU Assembly

    • Determines whether a collision is imminent based on the information received from the sensors. It then outputs a brake assist standby request signal and pre-collision brake request signal if required.

    • Operates the camera heater (forward recognition with heater hood sub-assembly) to remove condensation from the part of the windshield in front of the forward recognition camera.
    Brake Actuator Assembly Master Cylinder Pressure Sensor Detects the master cylinder pressure and transmits a signal to the skid control ECU.
    Pump Motor Receives an operation signal from the skid control ECU and generates hydraulic pressure for brake control.
    Skid Control ECU

    • Receives a brake assist standby request signal from the driving support ECU assembly and switches the brake assist to standby mode. When a master cylinder pressure signal is input, it activates the brake assist.

    • Receives a pre-collision brake request signal from the driving support ECU assembly, and then applies the brakes.

    • Transmits vehicle speed signals and stop light signal to the driving support ECU assembly.
    Speed Sensors Detect the wheel speed of each of the 4 wheels and transmits the signals to the skid control ECU.
    Airbag Sensor Assembly Detects the yaw rate and lateral/longitudinal deceleration of the vehicle and transmits the signal to the skid control ECU and the driving support ECU assembly.
    Steering Sensor Detects the angle and direction of steering and transmits a signal to the skid control ECU and driving support ECU assembly.
    ECM

    • Detects the shift position signal and accelerator pedal opening angle and sends that information to the driving support ECU assembly.

    • Performs engine output control based on information from the driving support ECU assembly.
    Stop Light Switch Assembly Detects if the brake pedal is depressed and transmits a signal to the skid control ECU.
    VSC OFF Switch Disables the pre-collision brake and pre-collision brake assist operation when VSC OFF mode.
    Combination Meter Assembly PCS Warning Light

    • Flashes or illuminates to warn the driver in accordance with signals from the driving support ECU assembly.

    • Flashes when the system is malfunctioning or temporarily disabled.

    • Illuminates when the pre-collision system is disabled.
    Multi-information Display

    • Displays a warning message to inform or warn the driver of the system condition in accordance with signals from the driving support ECU assembly.

    • Disables the pre-collision system operation when selected PCS OFF mode in setting display function.

    • Changing the pre-collision warning timing when selected Far/Middle/Near in setting display function.

    • Illuminates when pre-collision brake and pre-collision brake assist operation is disabled.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the driving support ECU assembly.
    Buzzer Sounds to warn the driver in accordance with signals from the driving support ECU assembly when the system is malfunctioning.
    Skid Control Buzzer Assembly Sounds to warn the driver in accordance with signals from the driving support ECU assembly.
    Main Body ECU (Multiplex Network Body ECU) Outputs the specification signal of the vehicle to driving support ECU.
    Network Gateway ECU Transmits the signal between the CAN communication bus.
    Steering Pad Switch Assembly Meter Control Switch Switch the display of multi-information display within combination meter assembly.

  2. FUNCTION


    1. The pre-collision system uses a millimeter wave radar sensor and forward recognition camera to detect vehicle in front of your vehicle.

    2. When the system determines that the possibility of a frontal collision with a vehicle is high, a warning operates to urge the driver to take evasive action and the potential brake pressure is increased to help the driver avoid the collision.

    3. If the system determines that the possibility of a frontal collision with a vehicle is extremely high, the brakes are automatically applied to help avoid the collision or help reduce the impact of the collision.


      1. Pre-collision warning

        When the system determines that the possibility of a frontal collision is high, a buzzer will sound and a warning message will be displayed on the multi-information display to urge the driver to take evasive action.

      2. Pre-collision brake assist

        When the system determines that the possibility of a frontal collision is high, the system applies greater braking force in relation to how strongly the brake pedal is depressed.

      3. Pre-collision braking

        If the system determines that the possibility of a frontal collision is extremely high, the brakes are automatically applied to help avoid the collision or reduce the collision speed.

  3. OPERATING CONDITION


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

    2. Each function is operational at the following speeds:


        Pre-collision warning:

      • Vehicle speed is between approximately 15 and 180 km/h (10 and 110 mph).

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


        Pre-collision brake assist:

      • Vehicle speed is between approximately 30 and 180 km/h (20 and 110 mph).

      • The relative speed between your vehicle and the vehicle ahead is approximately 30 km/h (20 mph) or more.


        Pre-collision braking:

      • Vehicle speed is between approximately 15 and 180 km/h (10 and 110 mph).

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

      The system may not operate in the following situations:


      • If a battery terminal has been disconnected and reconnected and then the vehicle has not been driven for a certain amount of time

      • If the shift lever is in R

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

      • If the PCS warning light is flashing or illuminated

    3. Cancelation of the pre-collision braking


      1. If either of the following occur while the pre-collision braking function is operating, it will be canceled:


        • The accelerator pedal is depressed strongly.

        • The steering wheel is turned sharply or abruptly.

      2. If the vehicle is stopped by the operation of the pre-collision braking function, the pre-collision braking function operation will be canceled after approximately 2 seconds. Depress the brake pedal as necessary.

    4. Conditions under which the system may operate even if there is no possibility of a collision


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


        • When passing a vehicle

        • When changing lanes while overtaking a preceding vehicle

        • When overtaking a preceding vehicle that is changing lanes

        • When overtaking a preceding vehicle that is making a left/right turn

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

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

        • When the approaching objects on the roadside, such as guardrails, utility poles, trees, or walls

        • 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 metal object (manhole cover, steel plate, etc.), steps, or a protrusion on the road surface or roadside

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

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        • When passing under an object (billboard, 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

        • When using an automatic car wash

        • When driving through or under objects that may contact the vehicle, such as thick grass, tree branches, or a banner

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

        • When driving through steam or smoke

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

        • When driving near an object that reflects radio waves, such as a large truck or guardrail

        • When driving near a TV tower, broadcasting station, electric power plant, or other location where strong radio waves or electrical noise may be present

  4. SYSTEM CONTROL


    1. Pre-collision Brake Assist


      1. When the driver depresses the brake pedal after the pre-collision system has determined that there is the possibility of a collision, brake fluid pressure is increased. If the possibility of a collision is still high, brake fluid pressure is further increased.

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    2. Pre-collision Braking


      1. When the pre-collision system determines that a collision is imminent, the system performs pre-collision braking control.

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  5. DIAGNOSIS


    1. Initial Check


      1. The driving support ECU assembly performs an initial check on the system for approximately 3 seconds after the engine switch has been turned on (IG).

    2. Monitor Function


      1. After completing the initial check, the pre-collision system becomes ready to operate. During this time, the driving support ECU assembly periodically monitors the system for any malfunctions.

    3. Diagnostic Trouble Code (DTC)


      1. If the driving support ECU assembly detects a malfunction in the pre-collision system, it stores a 5 digit Diagnostic Trouble Code (DTC) in memory.