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 a warning indication and warning sound.
Warning
•  The lane departure warning system (LDWS) is only a supplementary system for the prevention of a lane departure, however the lane departure warning system (LDWS) functions have limitations. Relying solely on the lane departure warning system (LDWS) and neglecting prudent steering wheel operation could cause an unexpected accident resulting in death or serious injury. Do not rely solely on the lane departure warning system (LDWS). Always make lane corrections using the steering wheel and drive safely.
•  The lane departure warning system (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 forward sensing camera (FSC) aiming is not completed correctly, the forward sensing camera (FSC) cannot record the camera shooting angle and the lane departure warning system (LDWS) may not operate normally. When performing the following servicing, always perform the forward sensing camera (FSC) aiming. In addition, for the FSC aiming procedure, refer to the [FORWARD SENSING CAMERA (FSC) AIMING] in the Workshop Manual.
―  Forward sensing camera (FSC) replacement
―  Forward sensing camera (FSC) clip replacement
―  Windshield replacement

Functions

•  The forward sensing camera (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. For details on the forward sensing camera (FSC) and warning-trigger lines, refer to [FORWARD SENSING CAMERA (FSC)]. (See FORWARD SENSING CAMERA (FSC).)

Driver operation determination function

•  The forward sensing camera (FSC) determines the following driving operations as the driver's intentions and controls the warning operation.
―  After the turn switch is operated, the vehicle lane is changed within 60 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 forward sensing camera (FSC) displays the system status using the multi-information display in the instrument cluster, and the warning display on the center display.

LDWS

Switch

Condition

Multi-information display

Center display
OFF
System is off
No display
ON
Vehicle lane lines are recognized at a vehicle speed of 65 km/h {40 mph} or more
While warning is triggered
Vehicle speed is 60 km/h {37 mph} or less
Vehicle lane lines are not recognized
Forward sensing camera (FSC) detects camera/windshield fogging
Warning display*1
Forward sensing camera (FSC) detects that the camera/windshield is dirty
Lane departure warning system (LDWS) has a malfunction
Forward sensing camera (FSC) has a malfunction

*1  :For the warning display content on the center display, refer to the [CENTER DISPLAY]. (See CENTER DISPLAY [WITH CENTER DISPLAY].)


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 signal of approx. 60 km/h {37 mph} or more is received from PCM (With lane-keep assist system)
―  Vehicle speed signal of approx. 65 km/h {40 mph} or more is received from PCM (Without lane-keep assist system)
―  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 until the vehicle travels within the warning-trigger lines for a period of 2 s.
•  One of the following two available types of warning sounds can be selected using the personalization feature. (Initial setting is rumble strip sound*1)
―  Beep sound output by instrument cluster
―  Rumble strip sound output by tuner and amplifier unit (TAU)
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*1  :A rumble strip is a series of grooves in the road pavement surface positioned at specific intervals, and when the vehicle passes over it a rumble sound is produced and an uncomfortable vibration can be felt which alerts the driver that the vehicle is departing from the lane lines. The rumble strip sound is a reproduction of the sound which occurs when a vehicle passes over a rumble strip.
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Rumble strip sound
1.  If the FSC determines that the vehicle has contacted a warning-trigger line, it sends (1) a warning sound request signal and a warning indication request signal to the radar unit.
2.  When the radar unit receives the warning sound request signal and the warning indication signal from the FSC, it determines (2) the priority order of the warning based on presence/non-presence of warning request from the MRCC system or the smart brake support (SBS).
3.  If the radar unit determines that the priority order of the warning sound request signal and the warning indication signal from the FSC is the highest, it sends the warning indication request signal (3) to the instrument cluster, and the warning sound request signal (4) to the connectivity master unit (CMU).
4.  When the instrument cluster receives the warning indication request signal from the radar unit, it flashes (5) the LDWS warning light(instrument cluster type B)/displays (5) the warning screen in the multi-information display.(instrument cluster type A).
5.  When the connectivity master unit (CMU) receives the warning sound request signal from the radar unit, it sends (6) the warning sound request signal to the tuner and amplifier unit (TAU).
6.  When the tuner and amplifier unit (TAU) receives the warning sound request signal from the connectivity master unit (CMU), it stops output from either the front left or right door speaker and outputs (7) a rumble strip sound.
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Beep sound
•  For the beep sound operation, refer to the [LANE DEPARTURE WARNING SOUND]. (See LANE DEPARTURE WARNING SOUND.)