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Home >> Toyota >> 2019 >> Corolla XLE >> Repair and Diagnosis (Single Page) >> Steering >> Steering Control Systems >> Lane Departure Alert System (W/ Steering Control) - Diagnostics - Introduction (Model Code: ZRE172) >> LANE DEPARTURE ALERT SYSTEM (W/ Steering Control) >> System Description [08/2016 - ] >> System Description [08/2016 - ]
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System Description [08/2016 - ]

  1. LANE DEPARTURE ALERT SYSTEM DESCRIPTION 
    1. When the vehicle is being driven on a highway or other roads, the lane departure alert system recognizes white (or yellow) lane markers and determines the position of the vehicle within the lane using the forward recognition camera and millimeter wave radar sensor assembly. If the system judges that the vehicle may deviate from the lane it is in, the system sounds a buzzer, illuminates the lane departure alert indicator in the combination meter display and performs steering assist so that the driver can take action to avoid lane departure.
  2. FUNCTION DESCRIPTION 
    FUNCTION DESCRIPTION
    Lane departure alert function If the system judges that the vehicle may deviate from the lane it is in, the system illuminates the lane departure alert indicator in the combination meter display and sounds a buzzer to inform the driver of a possibility of lane departure.
    LDA steering control function If the system judges that the vehicle may deviate from the lane it is in, the system illuminates the lane departure alert indicator in the combination meter display and performs steering assist to help the driver correct the path of the vehicle.
    Vehicle sway warning function If the system detects that the driver is inattentive based on the position of the vehicle within its lane and the steering inputs of the driver, it sounds the buzzer and illuminates the lane departure alert indicator in the combination meter display to inform the driver to stop and take a rest.

    HINT: 

    • Customized settings can be used to turn on/off each function, adjust sensitivities, etc.
    • The customized settings can be set by using the steering wheel pad switch assembly and are displayed on the multi-information display.
    • The last memory function, which resumes the settings that were set before the engine was stopped, is provided.
  3. SYSTEM SPECIFICATION 
    Operation speed Lane departure alert function Between approximately 50 and 270 km/h (32 and 167 mph)
    LDA steering control function
    Vehicle sway warning function    		 Between approximately 50 and 200 km/h (32 and 124 mph)
    Operation lane width More than approximately 3 m (9.8 ft.)
    Operation curve radius More than approximately 150 m (492 ft.)
  4. OPERATING CONDITIONS 
    1. Base Conditions:
      • The lane departure alert main switch is turned on.
      • The vehicle speed is within the operation conditions.
      • The vehicle is driving in a lane with a width within the operation conditions.
      • The vehicle is driving on a straight road or a road with a slight curve.
      • Lane markers are detected.
      • The turn signal switch is off.
      • The lane departure alert system has no malfunctions.
    2. Lane departure alert function can operate if all of the following base conditions are met:
      • The base conditions are met.
    3. LDA steering control function can operate if all of the following base conditions are met:
      • The base conditions are met.
      • "Steering Assist" on the settings screen on the multi-information display is set to "On".
      • The detected deceleration of the vehicle is not above a certain amount.
      • The system judges that the driver is operating the steering wheel with the intention of changing lanes.
      • The VSC system, pre-collision system or other vehicle safety system is not operating.
      • The detected acceleration of the vehicle is not above a certain amount.
    4. Vehicle sway warning function can operate if all of the following base conditions are met:
      • The base conditions are met.
      • "Vehicle Sway Warning" on the settings screen on the multi-information display is set to "On".
  5. CONTROL OF EACH FUNCTION 
    1. Lane departure alert function:
      1. Sensitivity: "Standard"

        A warning is output when a front wheel starts to cross a lane marker.

        HINT: 

        When the deviation speed (lateral travel speed) is slow, the warning may be output after the front wheel crosses over the lane marker.

      2. Sensitivity: "High"

        A warning is provided when a front wheel nears a lane marker.

        HINT: 

        When the deviation speed (lateral travel speed) is slow, the warning may be output after the front wheel crosses over the lane marker.

    2. LDA steering control function:
      1. If the system judges that the vehicle may deviate from its lane, this function performs steering assist to keep the vehicle parallel with its lane.
    3. Vehicle sway warning function:
      1. A warning is output when any of the following occurs:
        • The vehicle repeatedly deviates from its lane.
        • The vehicle drifts within its lane when the driver is inattentive.
        • After steering wheel inputs from an inattentive driver decrease, the steering wheel is turned abruptly.
  6. FUNCTION OF COMPONENTS 
    COMPONENTS FUNCTION
    Forward Recognition Camera
    • Detects lane markers and objects on the road ahead using the image captured by the monocular camera and generates information about the road
    • Sends a steering assist request signal to the power steering ECU assembly
    • Sends request signals to the combination meter assembly to display lane departure alert indicators and messages and sound the meter buzzer
    • Stores customize settings information
    Lane Departure Alert Main Switch (Steering Pad Switch Assembly) Turns on/off the lane departure alert system
    Function Switch (Steering Pad Switch Assembly) Changes the customize settings of the lane departure warning function, LDA steering control function and vehicle sway warning function
    Combination Meter Assembly
    • Displays messages on the multi-information display and turns on lane departure alert indicators based on request signals from the forward recognition camera
    • Sounds the meter buzzer based on request signals from the forward recognition camera
    • Sends meter tolerance and turn signal switch operation signals to the forward recognition camera
    • Sends customize settings information to the forward recognition camera
    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 motor
    • Sends steering wheel operation signals to the forward recognition camera
    • Cancels steering assist when an abnormal torque request signal is received from the forward recognition camera
    Steering Sensor Sends the turning angle of the steering wheel to the forward recognition camera
    Driving Support ECU Assembly
    • Sends the current status of the lane departure alert main switch to the forward recognition camera
    • Sends a buzzer request signal for the pre-collision system and dynamic radar cruise control system to the forward recognition camera
    Skid Control ECU (Brake Actuator Assembly) Sends the wheel speed, yaw rate zero point, brake operation status and other information to the forward recognition camera
    Yaw Rate Sensor (Airbag Sensor Assembly) Sends signals received from the yaw rate sensor to the forward recognition camera
    ECM Sends the accelerator pedal opening angle signal to the forward recognition camera
    Millimeter Wave Radar Sensor Assembly Sends the preceding vehicle information to the forward recognition camera
    Main Body ECU (Multiplex Network Body ECU) Sends the country specification information to the forward recognition camera
    Central Gateway ECU (Network Gateway ECU) Gateway function of CAN communication
  7. SYSTEM INOPERATIVE CONDITIONS 
    1. The lane departure alert system may not operate in any of the following conditions:
      • When driving through an area with no lane markers or such as a tollbooth.
      • When lane markers are obscured or cannot be recognized due to backlight, bad weather or standing water.
      • When driving in a location where the light level changes rapidly, such as the entrance to or exit from a tunnel.
      • When the tires are excessively worn or the tire inflation pressure is insufficient.
      • When non-standard tires are used (incorrect tire size or tire maker).
      • When winter tires or a spare tire is used.
      • When a non-standard suspension is installed.
      • When the road is partially covered in snow.
      • When there are shadows on the road running parallel with the lane markers.
      • When the lane markers are Bott's dots (raised pavement markers), stone, etc.
      • When there are markings on the road due to road repairs, etc.
      • When driving through a road construction area.
      • When turning a sharp corner.
      • When driving on a road that is branching or merging.
      • When a lane is extremely narrow or wide.
      • When driving on a particularly bright road surface, such as concrete.
      • When driving on a road surface that is bright due to reflected sunlight or the headlights of oncoming vehicles.
      • When driving on a road surface that is wet due to rain, standing water, etc.
      • When driving on a winding or uneven road.
      • When the distance between the vehicle and the preceding vehicle is extremely short.
      • When the vehicle experiences strong up-and-down motion such as when driving over a joint in the road surface or on an extremely rough road.
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