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
•  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 driving 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 for FSC and warning-trigger line details. (See FORWARD SENSING CAMERA (FSC).)

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 status display function

•  The FSC displays the system status using the LDWS indicator light (green), LDWS warning light (amber), active driving display (instrument cluster type A), and the multi-information display (instrument cluster type B).

LDWS

Switch

Condition

LDWS indicator light (green)

LDWS warning light (amber)

Master warning light

Active driving display (instrument cluster type A)

Multi-information display (instrument cluster type B)
OFF
System is off
Off
Off
Off
No display
No display
ON
Vehicle lanes recognized at vehicle speed of 70 km/h {43 mph} or more
On
Off
Off
While warning is triggered
Flash
Off
Off
Vehicle speed is 65 km/h {40 mph} or less
Off
On
Off
Vehicle lanes not recognized
Off
On
Off
FSC detects camera fogging
Off
Off
On
No display
FSC detects camera dirty
Off
Off
On
No display
Malfunction in LDWS occurs
Off
Flash
Off
No display
Malfunction in FSC occurs
Off
Off
On
No display


Structural View

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System Wiring Diagram

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Block diagram

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Operation


Operation conditions

•  The warning is triggered when all of the following conditions are met:
―  LDWS switch is on (system on)
―  Vehicle speed signal of 70 km/h {43 mph} or more from PCM is received
―  Vehicle contacts warning-trigger line unbeknownst to driver


Operation

•  The warning operation time differs depending on how long the vehicle contacts 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.
•  The warning operation sound has the following two types:
―  The warning operation sound (beep) is output from the instrument cluster.
―  The warning operation sound (rumble strip sound*1) is output from the tuner and amp unit.
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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 (With MRCC system)
1.  If the FSC determines that the vehicle has contacted a warning-trigger line, it sends a warning sound request signal and a warning indication signal to the vehicle control module.
2.  When the vehicle control module receives the warning sound request signal and the warning indication signal from the FSC, it determines 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 vehicle control module 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 to the instrument cluster, and the warning sound request signal to the connectivity master unit.
4.  When the instrument cluster receives the warning indication request signal from the vehicle control module (V/C-module), it flashes the LDWS indicator light (green) and displays the warning screen in the active driving display.
5.  When the CMU receives the warning sound request signal from the vehicle control module (V/C-module), it sends the warning sound request signal to the tuner and amp unit.
6.  When the tuner and amp unit receives the warning sound request signal from the CMU, it stops sound output from either the front left or right door speaker according to the request signal and outputs a rumble strip sound.
Note
•  If the user is conversing using the HF/TEL, or the voice recognition function is outputting voice, the rumble strip sound is not output.
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Rumble strip sound (Without MRCC system)
1.  If the FSC determines that the vehicle has contacted a warning-trigger line, it sends a warning indication request signal to the instrument cluster and a warning sound request signal to the connectivity master unit (CMU).
2.  When the instrument cluster receives the warning indication request signal from the FSC, it flashes the LDWS indicator light (green) and displays the warning screen in the active driving display (instrument cluster type A)/multi-information display (instrument cluster type B).
3.  When the CMU receives the warning sound request signal from the FSC, it sends the warning sound request signal to the tuner and amp unit.
4.  When the tuner and amp unit receives the warning sound request signal from the CMU, it stops sound output from either the front left or right door speaker according to the request signal and outputs a rumble strip sound.
Note
•  If the user is conversing using the HF/TEL, or the voice recognition function is outputting voice, the rumble strip sound is not output.
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Beep sound
•  For the operation, refer to LDWS WARNING ALARM. (See LDWS WARNING ALARM.)