LANE-KEEPING ASSIST SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Combination Meter Assembly LKA Main Indicator Light Illuminates or turns off to warn the driver in accordance with signals from the driving support ECU.
    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.
    Master Warning Light Illuminates to warn the driver in accordance with signals from the driving support ECU.
    Multi Buzzer Sounds to warn the driver in accordance with signals from the driving support ECU.
    Lane Recognition Camera Sensor Captures the road scene ahead of the vehicle and detects lane markers on the driving lane, and calculates the radius to the center of the lane, lane width, lateral deviation and heading angle deviation.
    Millimeter Wave Radar Sensor Radiates millimeter waves forward, uses the reflected millimeter waves for detecting the presence of a vehicle being driven ahead, the vehicle-to-vehicle distance, and the relative speed, and transmits these pieces of information to the driving support ECU. The millimeter wave radar sensor is the same as that used in the dynamic radar cruise control system. For details, see the Dynamic Radar Cruise Control System section.
    Driving Support ECU

    • Culcurates the amount of steering assist in accordance with signals from switches, ECUs and lane recognition camera sensor.

    • Transmits the indicator light illumination request signal, multi-information display indication request signal, and buzzer sound request signal to the combination meter assembly.
    Power Management Control ECU Relays a signal from each ECU.
    ECM Sends a signal from the cruise control switch and stop light switch assembly to the driving support ECU.
    Skid Control ECU

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

    • Sounds the skid control buzzer assembly in accordance with a request signal from the driving support ECU.
    Power Steering ECU Assembly Controls the power steering motor in accordance with signals from the driving support ECU.
    LKA Main Switch Detects on/off status of the system and transmits a signal to the driving support ECU.
    Cruise Control Switch Transmits the cruise control switch signal to the ECM.
    Headlight Dimmer Switch Assembly Transmits a turn signal command to the driving support ECU.
    Windshield Wiper Switch Assembly Transmits a windshield wiper switch signal to the driving support ECU.
    Stop Light Switch Assembly Detects the depressing of the brake pedal and transmits a signal to the ECM.
    Yaw Rate Sensor Detects yaw rate and transmits a signal to the driving support ECU.
    Speed Sensor Transmits a vehicle speed signal to the skid control ECU.
    Steering Column Assembly

    • Applies a steering assist force.

    • Detects the driver's steering input and transmits it to the power steering ECU assembly.
    Skid Control Buzzer Assembly Sounds on to warn the driver in accordance with signals from the skid control ECU.

  2. OPERATING CONDITION


    1. The lane-keeping assist system can be used by pressing the LKA main switch after the engine is started.

    2. The lane-keeping assist system operates as follows:

      Except Models for Britain
      LKA Main Switch Vehicle-to-vehicle Distance Control in Dynamic Radar Cruise Control System Lane-keeping Assist Function Lane Departure Warning Function
      Vehicle Speed: approx. 72 km/h (45 mph) to approx. 170 km/h (106 mph) Vehicle Speed: approx. 50 km/h (31 mph) to approx. 200 km/h (124 mph)
      Off Off Disabled Disabled
      On Off Disabled Enabled
      On (Set speed: 71 km/h [44 mph] or less) Disabled Enabled
      On (Set speed: 72 km/h [45 mph] or more) Enabled Enabled
      Models for Britain
      LKA Main Switch Vehicle-to-vehicle Distance Control in Dynamic Radar Cruise Control System Lane-keeping Assist Function Lane Departure Warning Function
      Vehicle Speed: approx. 72 km/h (45 mph) to approx. 170 km/h (106 mph) Vehicle Speed: approx. 48 km/h (30 mph) to approx. 200 km/h (124 mph)
      Off Off Disabled Disabled
      On Off Disabled Enabled
      On (Set speed: 71 km/h [44 mph] or less) Disabled Enabled
      On (Set speed:72 km/h [45 mph] or more) Enabled Enabled

      Tech Tips

      If the vehicle speed comes off from the above condition while the lane-keeping assist function is operating, the lane-keeping assist function is suspended and the lane departure warning function starts operating.

    3. Operating Conditions of Lane-keeping Assist Function

      Operation Condition
      Start

      The lane-keeping assist function is activated when all of the following conditions are met:


      • The LKA main switch is on.

      • The main switch of the cruise control switch is on.

      • The set speed of the vehicle-to-vehicle distance control in the dynamic radar cruise control system is between approx. 72 km/h (45 mph) and 170 km/h (106 mph).

      • The vehicle speed is between approx. 72 km/h (45 mph) and 170 km/h (106 mph).

      • Lane markers are detected.

      • No turn signal command is detected.

      • No stop light switch signal is detected.

      • The steering force input is not above a certain level.

      • At this time, the icon of the steering wheel and lane markers are indicated on the multi-information display while the lane-keeping assist function operates. If this item is not indicated on the multi-information display, this function is not activated when LKA main switch is pressed.
      Stand-by

      The lane-keeping assist function is suspended when any one of the following conditions is met:


      • The vehicle speed is not between approx. 72 km/h (45 mph) and 170 km/h (106 mph).

      • The turn signal command is detected.

      • The steering force input is above a certain level.

      • The windshield wiper switch position is high or low.

      • No lane markers are detected.

      • The vehicle is judged to have crossed a lane marker.

      • No steering force is detected for certain period of time.

      This function resumes when the conditions above are removed.
      Stop

      The lane-keeping assist function is stopped when any one of the following conditions is met:


      • The LKA main switch is off.

      • The dynamic radar cruise control system is canceled.

      • The temperature of the lane recognition camera sensor is abnormal.

      • The EPS system is malfunctioning or abnormal.

      • The lane-keeping assist system is malfunctioning.

      This function resumes when the following conditions are met:


      • The conditions of the start operation above are satisfied.

      • The lane-keeping assist system and the EPS system conditions are normal.

      • The LKA main switch is turned on again.

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

      • *: Models with entry and start system

    4. Operating Conditions of Lane Departure Warning Function

      Operation Condition
      Start

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


      • The LKA main switch is on.

      • The vehicle speed is between approx. 50 km/h (31 mph) and 200 km/h (124 mph).*1

      • The vehicle speed is between approx. 48 km/h (30 mph) and 200 km/h (124 mph).*2

      • Lane markers are detected.

      • No turn signal command is detected.

      • No stop light switch signal is detected.

      • The steering force input is not above a certain level.
      Stand-by

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


      • The vehicle speed is not between approx. 50 km/h (31 mph) and 200 km/h (124 mph).*1

      • The vehicle speed is not between approx. 48 km/h (30 mph) and 200 km/h (124 mph).*2

      • A turn signal command is detected.

      • The steering force input is above a certain level.

      • The windshield wiper switch position is high or low.

      • No lane markers are detected.

      • The stop light switch signal is detected.

      When the stand-by operation is activated, the lane departure warning function is suspended for at least 1 second. This function resumes when the conditions above are removed.
      Stop

      The lane departure warning 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.

      This function resumes when the following conditions are met:


      • The conditions of the start operation above are satisfied.

      • The lane-keeping assist system condition is normal.

      • The ignition switch (engine switch*3) is turned off and ON again to ensure normal operation, after the lane-keeping assist system has been stopped by a system malfunction.

      • *1: Except models for Britain

      • *2: Models for Britain

      • *3: Models with entry and start system

  3. FUNCTION


    1. Lane-keeping Assist Function


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

      2. The steering assist force is constantly calculated and controlled by the driving support ECU in accordance with the radius to the center of the lane, heading angle deviation and lateral deviation from the center of the lane.

      3. If the driving support ECU determines that the vehicle is deviating from the lane, the skid control ECU sounds the skid control buzzer assembly. At this time, the driving support ECU 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 alerts the driver by sounding the multi 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 is not activated even when the LKA main switch is turned on.

        A004MIIE02

    2. Lane Departure Warning Function


      1. The driving support ECU 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, vehicle speeds and front wheel positions. When the driving support ECU determines that the front wheel is about to cross the lane marker, the driving support ECU activates the lane departure warning function, displays a warning sign on the multi-information display, sounds the skid control buzzer assembly, and applies a small steering force by activating the power steering column 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.

        A004LNAE02

  4. CONSTRUCTION


    1. Lane Recognition Camera Sensor


      1. The lane recognition camera sensor is mounted near the overhead console and is used for the lane-keeping assist system.

      2. The lane recognition camera sensor captures the road image up to approximately 30 m (98 ft.) ahead of the vehicle.

      3. 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.

        A004MAH

        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 tire or suspension are replaced or adjusted.

        • Strong force is applied onto the lane recognition camera sensor.

        For details, refer to the AVENSIS Repair Manual.

      4. 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.

        A004LY7E01
        *1 Lane Recognition Camera Sensor
        *2 Lane recognition camera sensor captures an image of approximately 3 m to 4 m of line width (9 ft. to 13 ft. of line width)
        *3 Approx. 30 m (98 ft.)
        *4 Image processing range
        A004MIRE02

    2. Combination Meter Assembly

      A004M3ME02
      Text in Illustration
      *1 Multi-information Display *2 LKA Main Indicator Light
      *3 Master Warning Light - -

      1. The combination meter assembly illuminates the indicator lights or gives an indication on the multi-information display, and sounds a multi buzzer (which is built into the combination meter assembly) or skid control buzzer assembly in accordance with the respective condition.

        Function Condition A004LS4 A004M08 Multi-information Display Multi Buzzer Skid Control Buzzer Assembly
        Lane-keeping Assist Function in Operation Illuminates - A004M1P - -
        Lane-keeping Assist

        • Lane Departure Warning Function is in Operation

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

        		 Illuminates - A004LVS A004MGN A004LVL

        Sounds

        (No Steering Force Input is Detected for Certain Period of Time)

        Sounds

        (Lane Departure Warning Function is in Operation)
        Lane Departure Warning Function in Operation Illuminates - A004M2B - -
        Lane Departure Warning Warning Operating Illuminates - A004LSI A004MGN A004M7B - Sounds
        Lane Departure Warning No Lane Markers are Detected Illuminates - A004M3V - -
        Lane-keeping Assist No Lane Markers are Detected Illuminates - A004LRB Sounds -

        • Lane-keeping Assist

        • Lane Departure Warning

        • Temperature of Lane Recognition Camera Sensor is Abnormal

        • EPS System is Malfunctioning or Abnormal

        		 Illuminates - A004M6W - -

        • Lane-keeping Assist

        • Lane Departure Warning

        		 Malfunction Occurred - Illuminates A004LP3 Sounds -
        Lane Recognition Camera Sensor Angle Adjustment Illuminates - A004MHN Sounds -

  5. DIAGNOSIS


    1. If a malfunction occurs in the lane-keeping assist during cruise control, the driving support ECU cancels the lane-keeping assist, turns off the LKA main indicator light and the master warning light, sounds the multi buzzer, and displays a message on 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). When an intelligent tester II connects to DLC3, the DTC can be read. For details, refer to the Repair Manual.