LANE TRACING ASSIST SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Components Function
    Camera Sensor (Object 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.

    • Sends an operation signal to the camera heater.

    • Relays signals between the driving support ECU and the steering vibration and heater ECU.
    Camera Heater (Forward Recognition Hood with Heater Sub-assembly) The camera heater is heated according to signals from the camera sensor.
    Steering Wheel Assembly Steering Vibration and Heater ECU

    • Operates the steering wheel motor according to an eccentric motor operation request signal from the driving support ECU.

    • Uses the steering heater line to detect the electrostatic capacitance generated when the driver touched the steering wheel and sends a signal to the driving support ECU.
    Steering Wheel Motor Operates according to a signal from the steering vibration and heater ECU to vibrate the steering wheel assembly.
    Steering Heater Wire Detects the electrostatic capacitance generated when the driver touches the steering wheel.
    Combination Meter Assembly - Sends a turn signal command to the driving support ECU.
    LTA Indicator Illuminates or turns off in accordance with signals from the driving support ECU.
    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 driving support ECU.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the driving support ECU.
    Meter Buzzer Sounds to warn the driver in accordance with signals from the driving support ECU.
    Steering Pad Switch Assembly LTA Main Switch Detects the on/off status of the LTA system and sends a signal to the driving support ECU.
    Turn Signal Switch Sends a turn signal command to the steering sensor.
    Headup Display (Meter Mirror Sub-assembly) Displays the system condition in accordance with a signal from the driving support ECU.
    Power Steering ECU Assembly

    • Controls the power steering motor and performs steering assist based on signals received from the driving support ECU.

    • Detects steering operations performed by the driver and sends the operations to the driving support ECU.

    • Cancels steering assist when an abnormal control request signal is received from the camera sensor.
    Driving Support ECU Assembly

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

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

    • Controls the LTA system.

    • 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.
    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 driving support ECU.
    Yawrate Sensor Detects the yaw rate and sends a signal to the driving support ECU.
    Steering Sensor

    • Sends the turning angle of the steering wheel to the driving support ECU.

    • Sends a turn signal command to the combination meter assembly.
    Skid Control ECU Assembly Sends a vehicle speed signal to the driving support ECU assembly.
    Hybrid Vehicle Control ECU Assembly

    • Sends the shift position signal to the driving support ECU.

    • Sends the accelerator pedal opening angle signal to the driving support ECU.
    Blind Spot Monitor Sensor LH/RH

    • Projects radar waves from the blind spot monitor sensor to the blind spot monitor detection range to detect the presence of other vehicles, vehicle-to-vehicle distance and relative vehicle speed.

    • Sends the detection information to the driving support ECU.
    Front Side Radar Sensor LH/RH

    • Projects radar waves from the front side radar sensor to the nearby lane in front detection range to detect the presence of other vehicles, vehicle-to-vehicle distance and relative vehicle speed.

    • Sends the detection information to the driving support ECU.
    FR Steering Control ECU*1 Sends the information about front wheel turning angle control to the driving support ECU.
    RR Steering Control ECU*2 Sends the information about rear wheel turning angle control to the driving support ECU.
    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 VGRS system

    *2: Models with DRS system

  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 LTA main switch is on. (When the LTA main switch is pressed to turn on the LTA system, the LTA indicator illuminates.)

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

      • Lane markers or lane boundary 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 or lane boundary 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.

      • A malfunction is detected in the LTA system.

      • The temperature of the camera sensor is abnormal.
      Canceled/Resume

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


      • The LTA main switch is off.

      • The LTA system is temporarily stopped.

      • The LTA system is malfunctioning.

      • The power 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 LTA system condition returns to normal.

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

      Tech Tips

      *: If it is determined that departing the current lane could cause the vehicle to collide with a vehicle traveling in a neighboring lane, the lane departure alert system operates even while the turn signal lights are flashing.

    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 LTA main switch is on. (When the LTA main switch is pressed to turn on the LTA system, the LTA indicator illuminates.)

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

      • Lane markers or lane boundary 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 or lane boundary are detected.

      • Immediately after the lane departure control function is activated.

      • The yawrate sensor is malfunctioning.

      • If the steering angle speed reaches a certain amount.

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

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

      • 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.

      • A malfunction is detected in the LTA system.

      • The temperature of the camera sensor is abnormal.
      Canceled/Resume

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


      • The LTA main switch is off.

      • The LTA system is malfunctioning.

      • The LTA system is temporarily stopped.

      • The power 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 LTA system condition returns to normal.

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

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

      Tech Tips

      *: If it is determined that departing the current lane could cause the vehicle to collide with a vehicle traveling in a neighboring lane, the lane departure alert system operates even while the turn signal lights are flashing.

    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 LTA main switch is on. (When the LTA main switch is pressed to turn on the LTA system, the LTA indicator illuminates.)

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

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

      • When the system recognizes lane markers or the path of the preceding vehicle.

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

      • Steering assist 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.

      • When calculation for a signal required for the function to operate has completed.
      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 or the path of the preceding vehicle 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.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.

      • No steering wheel operation detected.

      • A malfunction is detected in the LTA system.

      • The temperature of the camera sensor is abnormal.
      Canceled/Resume

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


      • The LTA main switch is off.

      • The cruise control main switch is off.

      • The LTA system is temporarily stopped.

      • The LTA system is malfunctioning.

      • The power 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 LTA system condition returns to normal.

      • The power switch is turned off and on (IG) again to ensure normal operation, after the LTA 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.

      • When the steering assist function or lane centering function is running (or immediately after).

      • Detection of the lane width other than regulated.

      • Detection of the curve radius other than regulated.

      • A malfunction is detected in the LTA system.

      • The temperature of the camera sensor is abnormal.
      Canceled/Resume

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


      • The LTA system is malfunctioning.

      • The power 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 LTA system condition returns to normal.

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

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

  3. SYSTEM CONTROL


    1. LTA System Warning Operation


      1. Function Overview (Lane Departure Alert Function)


        • If the function judges that the vehicle may deviate from the lane or lane boundary it is in, the function 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.

          B003GS8E02

        • If the function judges that departing the current lane could cause a collision with a vehicle traveling in a neighboring lane even when the turn signal lights are on, it provides a warning.

          B003GJTE01
          *1 Warning

      2. Function Overview (Steering Assist Function)


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

          B003H2QE02

        • If the function judges that departed the current lane could cause a collision with a vehicle traveling in a neighboring lane even when the turn signal lights are on, it provides a warning and performs steering assistance.

          B003HC8E02
          *1 Steering Assist Function not Operated
          *2 Steering Assist
          *3 Steering Assist Function Operated

      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 function 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.

          B003H4AE05
          *1 Steering Assist
          *2 Control output level
          *3 This illustration is only for explanatory purposes.

        • The path of the preceding vehicle is used to help the driver to follow the preceding vehicle, when traffic, etc. makes it difficult or impossible to see lane markers.

          B003GHSE02
          *1 Preceding Vehicle
          *2 Own Vehicle
          *3 Driving Path of Preceding Vehicle

      4. Function Overview (Vehicle Sway Warning Function)


        • The function 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.

          B003H44E08
          *1 Warning
          *2 Buzzer
          *3 Display
          *4 This illustration is only for explanatory purposes.

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

          B003HF3E01

  4. FUNCTION


    1. The LTA system can be turned on/off by pressing the LTA main switch on the steering pad switch assembly while the hybrid system is started. (The on/off status of the system is retained even if the power switch is turned off.)

      B003H55C01
      *a LTA 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 in consideration of serviceability. The DTCs of malfunctioning parts can be read by connecting the Global TechStream (GTS). Refer to the Repair Manual for details.