LANE DEPARTURE WARNING SYSTEM (LDWS)

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Outline

• The Lane Departure Warning System (LDWS) recognizes vehicle lane lines on a road using the forward sensing camera (FSC) installed to the windshield, and if the vehicle departs from its lane unbeknownst to the driver, the system alerts the driver of the lane departure using warning indication and warning sound.

  Warning
  • LDWS is only a supplementary system for the prevention of a lane departure, however the LDWS functions have limitations. Relying solely on the LDWS and neglecting prudent steering wheel operation could cause an unexpected accident resulting in death or serious injury. Do not rely solely on the LDWS. Always make lane corrections using the steering wheel and drive safely.
  • The LDWS may not operate normally under the following conditions:
    ― Poor vehicle lane line visibility due to adverse weather (rain, snow, fog)
    ― Poor vehicle lane line visibility due to backlight, snow on the road, water puddles, road ruts
    ― Poor vehicle lane line visibility due to cracks and fissures in the vehicle lane
    ― Vehicle lane lines intersect with complexity due to additions or reductions of travel lanes
    ― Vehicle lane marking is not completely erased after road maintenance, two or more lane lines next to each other
    ― Vehicle lane lines not recognized due to vehicle ahead

  Caution
  • If the FSC aiming for the LDWS is not completed, the camera shot angle for the FSC cannot be recorded and the LDWS may not operate. When performing the following servicing, always perform the FSC aiming. Refer to the FSC aiming procedure in the workshop manual.
    ― FSC replacement
    ― FSC clip replacement
    ― Windshield replacement

Function

• The FSC sets warning-trigger lines based on the vehicle lane lines recognized by the camera, and if the vehicle contacts one of these warning-trigger lines it activates the warning indicator and warning sound. Refer to FORWARD SENSING CAMERA (FSC) for FSC and warning-trigger line details.

Driver operation determination function

  • The FSC determines the driver's intentions according to the following driving operations, and controls the warning-trigger operation.
    ― After the turn switch is operated and the vehicle lane is changed within 6 s.
    ― The steering wheel is turned at a certain angle or more, and the vehicle lane is changed.
    ― The accelerator pedal is depressed a certain amount or more, and the vehicle lane is changed.
    ― The brake pedal is depressed a certain amount or more and the vehicle departs from its lane.

System conditions display function

  • The FSC displays the system conditions using the LCD in the instrument cluster.

LDWS Switch | Condition | LCD
--- | --- | ---
ON | Vehicle lane lines recognized at vehicle speed of 65 km/h {40 mph} or more |
While warning is triggered |
Vehicle speed 60 km/h {37 mph} or less |
Vehicle lanes not recognized
• FSC detects camera fogging • FSC detects camera soiling • Malfunction in LDWS occurs • Malfunction in FSC occurs |
OFF | System is off |

Structural view

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System wiring diagram

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Block diagram

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Operation

Operation condition

  • The warning is triggered when all of the following conditions are met:
    ― LDWS switch is on (system on)
    ― Vehicle speed is 65 km/h {40 mph} or more
    ― Vehicle contacts warning-trigger line unbeknownst to driver

Operation

  • The period of time in which the warning is triggered differs by the period of time in which the vehicle is contacting the warning-trigger line.
    ― Vehicle contacts warning-trigger line for less than 1 s: Warning triggers for 1 s
    ― Vehicle contacts warning-trigger line for 1 s or more: Warning triggers for 1.5 s
  • If the warning is triggered one time, the warning will not trigger again if the vehicle travels within the warning-trigger lines for a period of 2 s.

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  1. If the FSC determines that the vehicle has contacted an warning-trigger line, it sends warning sound request signal and an system indication signal (warning screen) to the instrument cluster.
  2. When the instrument cluster receives the request signal from the FSC, it displays the warning screen in the LCD. In addition, the warning is sounded using the buzzer in the instrument cluster.

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