LANE-KEEPING ASSIST SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Components Function
    Combination Meter Assembly LKA Indicator Light Illuminates or turns off in accordance with signals from the forward recognition camera.
    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 forward recognition camera.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the forward recognition camera.
    Multi Buzzer Sounds to warn the driver in accordance with signals from the forward recognition camera.
    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 LKA system.

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

    • Receives vehicle information and turn signal light operation signals and sends a steering force signal to the power steering ECU assembly.
    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 transmits this information to the forward recognition camera.
    Driving Support ECU Assembly

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

    • Transmits the LKA main switch signal to the forward recognition camera.
    ECM Sends the accelerator pedal opening angle signal to the forward recognition camera.
    Headlight Dimmer Switch Assembly Transmits a turn signal command to the combination meter assembly.
    Brake Actuator Assembly Skid Control ECU Sends a vehicle speed signal from the speed sensor to the forward recognition camera and driving support ECU assembly.
    Steering Pad Switch Assembly LKA Main Switch Detects an on/off status of the system and transmits a signal to the forward recognition camera.
    Meter Control Switch Changes the customize settings of the lane center function, lane departure alert function, steering assist function and vehicle sway warning function.
    Airbag Sensor Assembly*1 Yawrate Sensor Detects yaw rate and transmits a signal to the forward recognition camera and driving support ECU assembly.
    Yawrate Sensor Assembly*2 Detects yaw rate and transmits a signal to the forward recognition camera and driving support ECU assembly.
    Steering Sensor Sends the turning angle of the steering wheel to the driving support ECU assembly.
    Power Steering ECU Assembly

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

    • Sends steering torque signals from the torque sensor to the power steering ECU assembly.

    • Detects steering operations performed by the driver and outputs the operations to the forward recognition camera and driving support ECU assembly.

    • Cancels steering assist when an abnormal torque request signal is received from the forward recognition camera.
    Steering Vibration ECU Controls the steering vibration according to signals from the forward recognition camera.
    Main Body ECU (Multiplex Network Body ECU) Sends country specification information signals to the forward recognition camera.
    Network Gateway ECU Gateway function of CAN communication.

    *1: Except Models with VDIM

    *2: Models with VDIM

  2. OPERATION CONDITION


    1. Operating Conditions of LKA System (Lane Departure Alert)

      Operation Condition
      Operating/Resume

      The LKA system (lane departure alert) 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 LKA system, the LKA indicator light illuminates.)

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

      • Lane markers are detected.

      • LKA system becomes activated when the turning signal is set to the opposite direction against the heading direction.

      • System malfunction is not detected.
      Suspended

      The LKA system (lane departure alert) 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.

      • A malfunction is detected in the LKA system.

      • The temperature of the forward recognition camera is abnormal.

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

      The LKA system (lane departure alert) is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The LKA system is malfunctioning.

      • Engine switch is turned off.

      The LKA system (lane departure alert) resumes when the following conditions are met:


      • The conditions to start operation listed above returns to are satisfied.

      • The LKA system condition returns to normal.

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

    2. Operating Conditions of LKA System (Steering Assist)

      Operation Condition
      Operating/Resume

      The LKA system (steering assist) 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 LKA system, the LKA indicator light illuminates.)

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

      • Lane markers are detected.

      • No turn signal command is detected.

      • System malfunction is not detected.

      • Steering assist available is selected via operation of the steering pad switch assembly.

      • 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.
      Suspended

      The LKA system (steering assist) is suspended when any one of the following conditions is met:


      • The vehicle speed is not approximately 50 km/h (32 mph) or more.

      • A turn signal command is detected.

      • No only one lane markers are detected.

      • Immediately after the lane departure control function is activated.

      • The airbag sensor (yawrate sensor) assembly is malfunctioning.

      • A malfunction is detected in the LKA system.

      • The deceleration sensor or steering 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.

      • Deceleration at or above a constant speed is detected.

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

      • Acceleration via operation of the accelerator pedal is detected.

      • The temperature of the forward recognition camera is abnormal.

      • No steering wheel operation detected.
      Canceled

      The LKA system (steering assist) is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The LKA system is malfunctioning.

      • The LKA system is temporarily stopped.

      • The engine switch is turned off.

      • Steering assist unavailable is selected via operation of the steering pad switch assembly.

      The LKA system (steering assist) resumes when the following conditions are met:


      • The conditions to start operation listed above returns to are satisfied.

      • The LKA system condition returns to normal.

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

      • Steering assist available is selected via operation of the steering pad switch assembly.

    3. Operating Conditions of LKA System (Lane Center)

      Operation Condition
      Operating/Resume

      The LKA system (lane center) is activated when all of the following conditions are met:


      • The steering assist is turned on using a meter control switch on the multi-information display.

      • The Lane center tracing is turned on using a meter control switch on the multi-information display.

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

      • Lane markers are detected.

      • Dynamic radar cruise control with full-speed range 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.

      • System malfunction is not detected.

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

      • Systems related to vehicle safety, such as the ABS, VSC and PCS system, do not operate.

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

      • Hands off steering wheel alert is not displayed.
      Suspended

      The LKA system (lane center) is suspended when any one of the following conditions is met:


      • Dynamic radar cruise control with full-speed range do not operate.

      • A turn signal command is detected.

      • One side of lane markers is not detected.

      • The airbag sensor (yawrate sensor) assembly is malfunctioning.

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

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

      • Deceleration at or above a constant speed is detected.

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

      • Acceleration via operation of the accelerator pedal is detected.

      • No steering wheel operation detected.

      • The deceleration sensor or steering sensor is malfunctioning.

      • Detection of the lane width other than regulated.

      • Detection of the curve radius regulated.
      Canceled

      The LKA system (lane center) is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The cruise control switch is off.

      • The LKA system is temporarily stopped.

      • The LKA system is malfunctioning.

      • Engine switch is turned off.

      • The steering assist is turned off using a meter control switch on the multi-information display.

      • The Lane center tracing is turned off using a meter control switch on the multi-information display.

      The LKA system (lane center) resumes when the following conditions are met:


      • The conditions to start operation listed above returns to are satisfied.

      • The LKA system condition returns to normal.

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

      • The steering assist is turned on using a meter control switch on the multi-information display.

    4. Operating Conditions of LKA System (Vehicle Sway Warning)

      Operation Condition
      Operating/Resume

      The LKA system (vehicle sway warning) is activated when all of the following conditions are met:


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

      • Lane markers are detected.

      • System malfunction is not detected.

      • The vehicle sway warning is turned on using a meter control switch on the multi-information display.
      Suspended

      The LKA system (vehicle sway warning) is suspended when any one of the following conditions is met:


      • The vehicle speed is not approximately 50 km/h (32 mph) or more.

      • A turn signal command is detected.

      • No lane markers are detected.

      • Immediately after the lane departure alert is activated.
      Canceled

      The LKA system (vehicle sway warning) is stopped when any one of the following conditions is met:


      • The LKA system is malfunctioning.

      • The LKA main switch is off.

      • The vehicle sway warning is turned off using a meter control switch on the multi-information display.

      The LKA system (vehicle sway warning) resumes when the following conditions are met:


      • The conditions to start operation listed above returns to are satisfied.

      • The LKA system condition returns to normal.

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

      • Steering assist available is selected via operation of the steering pad switch assembly.

  3. SYSTEM CONTROL


    1. LKA System Warning Operation


      1. Function Over View (Lane Departure Alert)


        • If the system judges that the vehicle may deviate from the lane it is in, the 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.

          B004Z1UE04
          *1 Buzzer or Steering Vibration
          *2 Warning

      2. Function Over View (Steering Assist)


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

          B004YWCE04
          *1 Steering Assist
          *2 Control output level
          *3 Example of vehicle behavior and control output

      3. Function Over View (Lane Center)


        • This function is linked with radar cruise control and provides there quired assistance by operating the steering wheel to keep the vehicle in its current lane.*

          *: When radar cruise control is not operating, the lane-keeping assist 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.

          B004ZAUE02
          *1 Steering Assist
          *2 Control output level
          *3 Example of vehicle behavior and control output

      4. Function Over View (Vehicle Sway Warning)


        • The 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.

          B004Z3WE03
          *1 Warning
          *2 Buzzer and Warning Display

  4. FUNCTION


    1. Using the Meter Control Switches of the steering pad switch assembly, the LKA system settings functions and the vehicle sway warning functions can be customized.

      B004Z86C04
      *a LKA Main Switch *b Meter Control Switches

    2. Customize LKA system Settings Functions

      Item (Select using the up/down button of the meter control switch) Description Setting (Change using the center button of the meter control switch)
      Lane Center Tracing Select to enable/ disable the lane center function

      • ON

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

      • ON

      • OFF
      Warning Sensitivity Timing of lane departure alert

      • Normal

      • High
      Warning Method Lane departure alert method

      • Alert

      • Steering Vibration

    3. Customize Vehicle Sway Warning Functions

      Item (Select using the up/down button of the meter control switch) Description Setting (Change using the center button of the meter control switch)
      Vehicle Sway Warning Vehicle sway warning function

      • ON

      • OFF
      Vehicle Sway Detection Sensitivity Vehicle sway detection sensitivity

      • High

      • Normal

      • Low

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

      B004ZBGE08

  5. DIAGNOSIS


    1. If a malfunction is detected in the LKA system the forward recognition camera cancels the LKA system, Illuminates the LKA indicator light in yellow and illuminates the master warning light, sounds the multi buzzer in the combination meter assembly, and displays a message on the multi-information display to inform the driver of the malfunction.

    2. At the same time, the malfunction is stored in memory as a Diagnostic Trouble Code (DTC). When a Global TechStream (GTS) is connected to the DLC3, the DTC can be read. For details, refer to the Repair Manual.