LANE-KEEPING ASSIST SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Components Function
    Camera Sensor (Forward Recognition Camera)

    • Captures a view of the road ahead of the vehicle and detects lane markers on the driving lane, and calculates the radius to the center of the lane, lane width, distance from markers and heading angle deviation.

    • Controls the lane departure alert function, steering assist function and vehicle sway warning function.

    • Sends the indicator illumination request signal, multi-information display indication light request signal, and meter buzzer sound request signal to the combination meter assembly.

    • Sends the system condition signal to the headup display.

    • Receives vehicle information and turn signal light operation signals and sends a steering force signal to the power steering ECU.

    • Sends an operation signal to the camera heater.
    Camera Heater (Forward Recognition Hood with Heater Sub-assembly) The camera heater is heated according to signals from the camera sensor.
    Steering Vibration and Heater ECU Operates the steering wheel motor according to an eccentric motor operation request signal from the camera sensor.
    Steering Wheel Motor Operates according to a signal from the steering vibration and heater ECU to vibrate the steering wheel assembly.
    Driving Support ECU Assembly

    • Calculates the amount of steering assist in accordance with signals from switches and ECUs.

    • Controls the lane centering function.
    Millimeter Wave Radar Sensor Assembly Radiates millimeter radar waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance, and the relative speed, and then sends this information to the camera sensor.
    Combination Meter Assembly - Sends a turn signal command to the camera sensor.
    LKA Indicator Illuminates or turns off in accordance with signals from the camera sensor.
    Multi-information Display Displays a warning message and white lines to inform or warn the driver of the system condition in accordance with signals from the camera sensor.
    Master Warning Indicator Illuminates to warn the driver in accordance with signals from the camera sensor.
    Meter Buzzer Sounds to warn the driver in accordance with signals from the camera sensor.
    ECM Sends the shift position signal to the camera sensor.
    Skid Control ECU Assembly*1 Sends a vehicle speed signal to the camera sensor.
    Skid Control ECU*2
    Steering Pad Switch Assembly LKA Main Switch Detects the on/off status of the lane keeping assist system and sends a signal to the camera sensor.
    Yawrate Sensor Detects the yaw rate and sends a signal to the camera sensor.
    Steering Sensor

    • Sends the turning angle of the steering wheel to the camera sensor.

    • Sends a turn signal command to the combination meter assembly.
    Turn Signal Switch Sends a turn signal command to the steering sensor.
    Power Steering ECU

    • Controls the power steering motor and performs steering assist based on signals received from the camera sensor.

    • Detects steering operations performed by the driver and sends the operations to the camera sensor.

    • Cancels steering assist when an abnormal control request signal is received from the camera sensor.
    Headup Display (Meter Mirror Sub-assembly)*3 Displays the system condition in accordance with a signal from the camera sensor.
    Central Gateway ECU (Network Gateway ECU) Relays the signal between the CAN communication buses.
    DLC3 The Global TechStream (GTS) can be connected to read the Diagnostic Trouble Codes (DTCs) of malfunctions.

    *1: Models with electronically controlled brake system

    *2: Models with vacuum brake booster

    *3: Models with headup display

  2. OPERATION CONDITION


    1. Operating Conditions of Lane Departure Alert Function

      Operation Condition
      Operating

      The lane departure alert function is activated when all of the following conditions are met:


      • The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)

      • The vehicle speed is approximately 50 km/h (32 mph) or more.

      • Lane markers are detected.

      • No turn signal command is detected.

      • A system malfunction is not detected.
      Suspended

      The lane departure alert function is suspended when any one of the following conditions is met:


      • The vehicle speed is less than approximately 50 km/h (32 mph).

      • A turn signal command is detected.

      • No lane markers are detected.

      • Immediately after the lane departure alert is activated.

      • The vehicle crosses halfway or further over a lane marker.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.
      Canceled/Resume

      The lane departure alert function is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The lane keeping assist system is temporarily stopped.

      • The lane keeping assist system is malfunctioning.

      • The engine switch is turned off.

      The lane departure alert function resumes when the following conditions are met:


      • The conditions to start operation listed above are satisfied.

      • The lane keeping assist system condition returns to normal.

      • The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

    2. Operating Conditions of Steering Assist Function

      Operation Condition
      Operating

      The steering assist function is activated when all of the following conditions are met:


      • The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)

      • The vehicle speed is approximately 50 km/h (32 mph) or more.

      • Lane markers are detected.

      • No turn signal command is detected.

      • A system malfunction is not detected.

      • Steering assist is turned "On" via customized combination meter assembly settings.

      • Deceleration at or above a constant speed is not detected.

      • Steering operations to change the direction of vehicle travel are not performed.

      • Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate.

      • Acceleration via operation of the accelerator pedal is not detected.

      • The hands off steering wheel alert is not displayed.
      Suspended

      The steering assist function is suspended when any one of the following conditions is met:


      • The vehicle speed is less than approximately 50 km/h (32 mph).

      • A turn signal command is detected.

      • No lane markers are detected.

      • Immediately after the lane departure control function is activated.

      • The yawrate sensor is malfunctioning.

      • The vehicle crosses halfway or further over a lane marker.

      • Steering assist generated to change the direction of vehicle travel is detected.

      • If the steering angle speed reaches a certain amount.

      • Deceleration at or above a constant speed is detected.

      • Systems related to vehicle safety, such as the VSC and pre-collision system, operate.

      • Acceleration via operation of the accelerator pedal is detected.

      • No steering wheel operation detected.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.
      Canceled/Resume

      The steering assist function is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The lane keeping assist system is malfunctioning.

      • The lane keeping assist system is temporarily stopped.

      • The engine switch is turned off.

      • Steering assist is turned "Off" via customized combination meter assembly settings.

      The steering assist function resumes when the following conditions are met:


      • The conditions to start operation listed above are satisfied.

      • The lane keeping assist system condition returns to normal.

      • The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

      • Steering assist is turned "On" via customized combination meter assembly settings.

    3. Operating Conditions of Lane Centering Function

      Operation Condition
      Operating

      The lane centering function is activated when all of the following conditions are met:


      • The LKA main switch is on. (When the LKA main switch is pressed to turn on the lane keeping assist system, the LKA indicator illuminates.)

      • Steering assist is turned "On" via customized combination meter assembly settings.

      • Lane center is turned "On" via customized combination meter assembly settings.

      • Lane markers are detected.

      • Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) is operating.

      • The vehicle is driving in a lane with a width of operation condition of each function

      • Lane departure control function is not operating.

      • No turn signal command is detected.

      • A system malfunction is not detected.

      • Deceleration at or above a constant speed is not detected.

      • Steering operations to change the direction of vehicle travel are not performed.

      • Systems related to vehicle safety, such as the VSC and pre-collision system, do not operate.

      • Acceleration via operation of the accelerator pedal is not detected.

      • The hands off steering wheel alert is not displayed.
      Suspended

      The lane centering function is suspended when any one of the following conditions is met:


      • Dynamic radar cruise control system (vehicle-to-vehicle distance control mode) do not operate.

      • A turn signal command is detected.

      • One side of lane markers is not detected.

      • The yawrate sensor is malfunctioning.

      • The vehicle crosses halfway or further over a lane marker.

      • Steering operations to change the direction of vehicle travel are performed.

      • If the steering angle speed reaches a certain amount.

      • Deceleration at or above a constant speed is detected.

      • Systems related to vehicle safety, such as the VSC and pre-collision system, operate.

      • Acceleration via operation of the accelerator pedal is detected.

      • The steering sensor is malfunctioning.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.
      Canceled/Resume

      The lane centering function is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The cruise control main switch is off.

      • The lane keeping assist system is temporarily stopped.

      • The lane keeping assist system is malfunctioning.

      • The engine switch is turned off.

      • Steering assist is turned "Off" via customized combination meter assembly settings.

      • Lane center is turned "Off" via customized combination meter assembly settings.

      The lane centering function resumes when the following conditions are met:


      • The conditions to start operation listed above are satisfied.

      • The lane keeping assist system condition returns to normal.

      • The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

      • Steering assist is turned "On" via customized combination meter assembly settings.

      • Lane center is turned "On" via customized combination meter assembly settings.

    4. Operating Conditions of Vehicle Sway Warning Function

      Operation Condition
      Operating

      The vehicle sway warning function is activated when all of the following conditions are met:


      • Sway warning is turned "On" via customized combination meter assembly settings.

      • The vehicle speed is approximately 50 km/h (32 mph) or more.

      • Lane markers are detected.

      • A system malfunction is not detected.

      • No turn signal command is detected.
      Suspended

      The vehicle sway warning function is suspended when any one of the following conditions is met:


      • The vehicle speed is less than approximately 50 km/h (32 mph).

      • One side of lane markers is not detected.

      • A turn signal command is detected.

      • Immediately after the lane departure alert is activated.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.
      Canceled/Resume

      The vehicle sway warning function is stopped when any one of the following conditions is met:


      • The lane keeping assist system is malfunctioning.

      • The engine switch is turned off.

      • Sway warning is turned "Off" via customized combination meter assembly settings.

      The vehicle sway warning function resumes when the following conditions are met:


      • The conditions to start operation listed above are satisfied.

      • The lane keeping assist system condition returns to normal.

      • The engine switch is turned off and on (IG) again to ensure normal operation, after the lane keeping assist system has been stopped by a system malfunction.

      • Sway warning is turned "On" via customized combination meter assembly settings.

  3. SYSTEM CONTROL


    1. Lane Keeping Assist System Warning Operation


      1. Function Overview (Lane Departure Alert Function)


        • If the lane keeping assist system judges that the vehicle may deviate from the lane it is in, the lane keeping assist system illuminates the indicator in the combination meter display and vibrates the steering wheel or sounds a buzzer so that the driver can take action to avoid lane departure.

          B0056EXE03
          *1 Buzzer
          *2 Display
          *3 Steering Vibration
          *4 This illustration is only for explanatory purposes.

      2. Function Overview (Steering Assist Function)


        • If the lane keeping assist system judges that the vehicle may deviate from the lane it is in, the lane keeping assist system performs steering assist to help the driver correct the path of the vehicle. If the driver does not take appropriate action, the lane keeping assist system sounds a meter buzzer or vibrates the steering wheel.

          B00564UE03

      3. Function Overview (Lane Centering Function)


        • The lane centering function is linked with the dynamic radar cruise control system (vehicle-to-vehicle distance control mode) and provides the required assistance by operating the steering wheel to keep the vehicle in its current lane.*

          Tech Tips

          *: When the dynamic radar cruise control system (vehicle-to-vehicle distance control mode) is not operating, the lane centering function does not operate. If the system detects that the steering wheel has not been operated for a fixed amount of time or the steering wheel is not being firmly gripped, a warning is displayed on the multi-information display and the function is temporarily canceled.

          B0056QXE05
          *1 Steering Assist
          *2 Control output level
          *3 This illustration is only for explanatory purposes.

      4. Function Overview (Vehicle Sway Warning Function)


        • The lane keeping assist system detects drift of the vehicle within its lane, which is often the result of a driver who is tired, distracted or not looking ahead, based on the position of the vehicle within its lane and the steering inputs of the driver, to alert the driver before a lane departure or collision occurs.

          B0056G0E08
          *1 Warning
          *2 Buzzer
          *3 Display
          *4 This illustration is only for explanatory purposes.

        • The vehicle sway warning function provides a warning to alert the driver when any of the following conditions occur:

          B0056T6E09

  4. FUNCTION


    1. The lane keeping assist system can be turned on/off by pressing the LKA main switch on the steering pad switch assembly while the engine is started. (The on/off status of the system is retained even if the engine switch is turned off.)

      B00567WC02
      *a LKA Main Switch - -

    2. Lane Keeping Assist System Settings Functions Customization

      Item Description Setting
      Lane Center Select to enable/disable the lane centering function

      • On

      • Off
      Steering Assist Select to enable/disable steering wheel assistance

      • On

      • Off
      Alert Warning Method

      • Buzzer

      • Steering Vibration
      Sensitivity Timing of the lane departure alert

      • High

      • Standard
      Sway Warning Select to enable/disable the vehicle sway warning function

      • On

      • Off
      Sway Sensitivity Timing of the vehicle sway warning function

      • High

      • Standard

      • Low

  5. DIAGNOSIS


    1. In order to make system inspections easier to perform, a diagnosis function is used inconsideration of serviceability. The DTCs of malfunctioning parts can be read by connecting the Global TechStream (GTS). Refer to the Repair Manual for details.