LANE-KEEPING ASSIST SYSTEM DETAILS


  1. FUNCTION OF MAIN COMPONENTS

    Components Outline
    Lane Recognition Camera Sensor Assembly Captures an image of the road ahead of the vehicle, detects lane markers of the driving lane, and calculates the deviation from the center of the lane, yaw angle and radius of curves.
    LKA Main Switch Sends the on/off state to the driving support ECU assembly.
    Driving Support ECU Assembly

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

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

    • Sends a buzzer sound request signal to the skid control buzzer assembly.
    Skid Control ECU Assembly

    • Sends the vehicle speed signal from the speed sensor to the driving support ECU assembly.

    • Sounds the skid control buzzer assembly in accordance with a request signal from the driving support ECU assembly.
    Power Steering ECU Assembly

    • Controls the power steering motor in accordance with signals from the driving support ECU.

    • Transmits the driver's steering input signal to the driving support ECU assembly.
    Combination Meter Assembly LKA Indicator Light Illuminates to warn the driver in accordance with signals from the driving support ECU assembly.
    Multi-information Display Displays a message to inform or warn the driver of the system condition in accordance with signals from the driving support ECU assembly.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the driving support ECU assembly.
    Multi Buzzer Sounds to warn the driver in accordance with signals from the driving support ECU assembly.
    Combination Meter Mirror ECU* Shows the lane departure warning display in accordance with a signal from the combination meter assembly.
    Steering Column Assembly Power Steering Motor Applies a steering assist force.
    Torque Sensor Detects the driver's steering input and transmits it to the power steering ECU assembly.
    Skid Control Buzzer Assembly Sounds to warn the driver in accordance with signals from the skid control ECU assembly.
    Millimeter Wave Radar Sensor Assembly Detects the vehicle ahead and transmits the distance to the vehicle ahead to the lane recognition camera sensor assembly.
    Yawrate Sensor Detects yaw rate and acceleration and transmits a signal to the driving support ECU assembly.
    Speed Sensor Transmits the vehicle speed signal to the skid control ECU assembly.
    Cruise Control Main Switch Transmits the cruise control main switch signal to the ECM.
    Stop Light Switch Assembly Detects the depressing of the brake pedal and transmits a signal to the ECM.
    Headlight Dimmer Switch Assembly Transmits a turn signal command to the driving support ECU assembly.
    ECM Sends a signal from the cruise control main switch and stop light switch assembly to the driving support ECU assembly.

    • *: Models with headup display

  2. OPERATING CONDITION


    1. Lane-keeping Assist System Operating Conditions


      1. The lane-keeping assist system can be activated by pressing the LKA main switch. At this time, the LKA indicator light in the combination meter assembly illuminates.

      2. The operating conditions of the lane-keeping assist system lane departure warning function and lane-keeping assist function differ in accordance with the on/off status of the dynamic radar cruise control system and the vehicle speed.

        LKA Main Switch Dynamic Radar Cruise Control System Vehicle Speed Function
        ON OFF Approximately 48 km/h to 200 km/h (30 mph to 125 mph) Lane Departure Warning
        ON Approximately 48 km/h to 72 km/h (30 mph to 45 mph) Lane Departure Warning
        Approximately 72 km/h to 180 km/h (45 mph to 112 mph) Lane-keeping Assist
        Approximately 180 km/h to 200 km/h (112 mph to 125 mph) Lane Departure Warning

    2. Lane-keeping Assist System Cancel Conditions


      1. The lane departure warning function and the lane-keeping assist function suspension conditions are as follows. However, if it is confirmed that the conditions which caused operation to be suspended are canceled, the system will be reactivated.

        Lane Departure Warning Function
        The vehicle speed is not between approximately 48 km/h and 200 km/h (30 mph and 125 mph).
        The turn signal command is detected.
        The steering force input is above a certain level.
        No lane markers are detected.
        The yawrate sensor is malfunctioning.
        Immediately after the lane departure warning is activated. However, if a few seconds has elapsed and it is confirmed that the vehicle is running inside lane markers, the system will be reactivated.
        Lane-keeping Assist Function
        The vehicle speed is not between approximately 72 km/h (45 mph) or and 180 km/h (112mph).
        The turn signal command is detected.
        The steering force input is above a certain level.
        The windshield wiper switch position is high.
        No lane markers are detected.
        The yawrate sensor is malfunctioning.
        More than approximately half of the vehicle is judged to have crossed a lane marker.
        No steering force is detected for a certain period of time.

    3. Lane-keeping Assist System Stop Conditions


      1. The lane departure warning function and the lane-keeping assist function stop, and restart conditions are as follows:

        Lane Departure Warning Function
        Stop Condition Restart Condition
        The LKA main switch is turned off The LKA main switch is turned on.
        The system is temporarily stopped

        The system will be reactivated if following conditions are met:


        • The LKA main switch is turned on again.

        • The LKA system condition is normal.
        The system is malfunctioning

        The system will be reactivated if following conditions are met:


        • The engine switch is turned on (IG) again.

        • The LKA main switch is turned on again.

        • The LKA system condition is normal.
        The engine switch is turned off The LKA main switch is turned on after the engine switch is turned on (IG) again.
        Lane-keeping Assist Warning Function
        Stop Condition Restart Condition
        The LKA main switch is turned off LKA main switch is turned on.
        The dynamic radar cruise control system is canceled* Dynamic radar cruise control is turned on again.
        The brake is operated* Dynamic radar cruise control is turned on again.
        The system is temporarily stopped If the LKA main switch is in on state, the system will be automatically reactivated after the temporary stop is canceled.
        The system is malfunctioning

        The system will be reactivated if following conditions are met:


        • The engine switch is turned on (IG) again.

        • The LKA main switch is turned on again.

        • The LKA system condition is normal.
        The engine switch is turned off The LKA main switch is turned on after the engine switch is turned on (IG) again.

        Tech Tips

        *: Automatically switches to the lane departure warning function.

  3. SYSTEM CONTROL


    1. The lane-keeping assist system has the following functions:

      Function Outline
      Lane Departure Warning When the system determines that the vehicle is about to deviate from its lane, the system urges the driver to correct the lane deviation by displaying a warning message, sounding the buzzer and applying a small amount of steering force.
      Lane-keeping Assist When cruise control is in operation, the system applies a small amount of steering force using EPS to assist driver's steering operation.

    2. Lane Departure Warning Function


      1. The driving support ECU assembly calculates the estimated position which the front wheel will reach after approximately 1 second based on the information collected by the lane recognition camera sensor assembly, vehicle speeds and front wheel positions. When the driving support ECU assembly determines that the front wheel is about to cross the lane marker, the driving support ECU assembly activates the lane departure warning function, displays a warning message on the multi-information display and headup display, sounds the skid control buzzer assembly, and applies a small amount of steering force by activating the power steering motor for approximately 1 second to urge the driver to correct the steering.

      2. The lane departure warning function does not operate if the vehicle approaches the lane marker (but does not cross it), as long as the vehicle remains parallel with the lane marker.

        A01FBQ3E01

    3. Lane-keeping Assist Function


      1. The driving support ECU assembly activates the power steering motor via the power steering ECU assembly based on the road information collected by the lane recognition camera sensor assembly and assists in the driver's steering operation to keep the vehicle near the center of the lane.

      2. The driving support ECU assembly constantly calculates and controls the steering assist force in accordance with the radius of the curve on the lane, heading angle deviation and lateral deviation from the center of the lane.

      3. If the driving support ECU assembly determines that the vehicle is deviating from the lane, the skid control ECU assembly sounds the skid control buzzer assembly. At this time, the driving support ECU assembly displays a warning message on the multi-information display to warn the driver of lane deviation.

      4. If the driver's steering input is not detected for a certain period, the driving support ECU assembly alerts the driver by sounding the buzzer in the combination meter assembly and by displaying a message on the multi-information display.

      5. The lane-keeping assist function is activated when the LKA main switch is turned on while the steering wheel icon is indicated on the multi-information display. If the icon is not displayed, the function will not be activated when the LKA main switch is turned on.

        A01FBTUE01

  4. FUNCTION


    1. Combination Meter Assembly


      1. The combination meter assembly provides a master warning light, LKA indicator light, multi buzzer, and multi-information display to provide warnings and messages regarding the lane-keeping assist system in accordance with functions. In addition, the skid control buzzer will sound when the warning is operated.

      2. The multi-information display displays the lane departure warning function, lane-keeping assist function, and warning message. During the operation of each function, the lane marker icons will be displayed in bold.

        Lane Departure Warning Function (LKA Main Switch On and Radar Cruise Control System Off)
        Condition Multi-information Display LKA Indicator Light Multi Buzzer Skid Control Buzzer Assembly

        • Approximately 48 km/h to 200 km/h (30 mph to 125 mph)

        • Lane Markers Detected

        		 A01FCE6 Illuminates - -

        • Approximately 48 km/h to 200 km/h (30 mph to 125 mph)

        • One Side of Lane Markers Detected

        		 A01FC7S
        Warning Operating A01FC49E01 Illuminates - Sounds Countinuously

        • Approximately 48 km/h (30 mph) or Higher

        • Lane Markers Not Detected

        		 A01FBSC Illuminates - -
        Below Approximately 48 km/h (30 mph)
        Lane-keeping Assist Function (LKA Main Switch On and Radar Cruise Control System On)
        Condition Multi-information Display LKA Indicator Light Multi Buzzer Skid Control Buzzer Assembly

        • Approximately 72 km/h to 180 km/h (45 mph to 112 mph)

        • Lane Markers Detected

        		 A01FBYF Illuminates - -

        • Approximately 72 km/h to 180 km/h (45 mph to 112 mph)

        • Lane Markers Detected

        • Lane Deviation Warning Operating

        		 A01FC5RE01 Illuminates - Sounds Countinuously

        • Approximately 72 km/h to 180 km/h (45 mph to 112 mph)

        • Lane Markers Detected

        • No Steering Force Input is Detected for Certain Period of Time

        		 A01FBM3 Illuminates Sounds Twice -

        • Below Approximately 72 km/h (45 mph) or 180 km/h (112 mph) or Higher

        • Lane Markers Detected

        		 A01FBOH Illuminates - -

        • Below Approximately 72 km/h (45 mph) or 180 km/h (112 mph) or Higher

        • One Side of Lane Marker Detected

        		 A01FBWD Illuminates - -
        Lane Marker Not Detected A01FBXL Illuminates - -
        Warning Massage
        Condition Multi-information Display LKA Indicator Light Master Warning Light Multi Buzzer

        • Temperature of Lane Recognition Camera Sensor is Abnormal.

        • EPS System is Malfunctioning or Abnormal.

        		 A01FC24 Illuminates Illuminates -
        System Malfunction A01FBUW - Illuminates Sounds
        Lane Recognition Camera Sensor Angle Adjustment A01FBKX Illuminates - -

    2. Headup Display


      1. The headup display displays the lane departure warning function. During the operation of the lane departure warning function, the lane marker icons will be displayed in bold.

        Lane Departure Warning Function
        Condition Headup Display
        Warning Operating A01FBWC

  5. CONSTRUCTION


    1. Lane Recognition Camera Sensor Assembly


      1. The lane recognition camera sensor assembly is mounted at the top center portion of the top part of the windshield.

        A01FC38

        Tech Tips

        When one of the following operations is conducted, the lane recognition camera sensor angle must be adjusted:


        • The lane recognition camera sensor is removed and reinstalled or replaced.

        • Parts relating to the suspension are adjusted or replaced.

        For details, refer to the Repair Manual.

      2. The lane recognition camera sensor assembly captures an image of the road up to approximately 30 m (98 ft.) ahead of the vehicle. In addition, the detectable lane width is approximately 3 m to 4 m (9 ft. to 13 ft.).

        A01FCDNE01
        Text in Illustration
        *1 Lane Recognition Camera Sensor Assembly - -
        *a Lane Marker *b Image Processing Range
        *c Approximately 3 m to 4 m (9 ft. to 13 ft.) *d Approximately 30 m (98 ft.)

      3. By processing the road image data, the lane recognition camera sensor detects lane markers and calculates the radius to the center of the lane, heading angle deviation, lateral deviation from the center of the lane, and the lane width.

        A01FBZKE01
        Text in Illustration
        *a Image Captured by Lane Recognition Camera Sensor Assembly *b Left Lane Marker
        *c Center of Lane *d Right Lane Marker
        *e Radius to Center of Lane *f Heading Angle Deviation
        *g Lateral Deviation *h Lane Width

  6. DIAGNOSIS


    1. If a malfunction is detected in the lane-keeping assist system, the driving support ECU assembly stops the system, turns off the LKA indicator light, illuminates the master warning light, sounds the multi buzzer, and outputs a warning message on the multi-information display to inform the driver of the malfunction. At the same time, the malfunction is stored in memory as a Diagnostic Trouble Code (DTC).