steering LEXUS RX450H 2019 Service Manual

2974-5. Using the driving support systems
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Driving
RX450h_RX450hL_U
When driving on highways and freeways with white or yellow lines, this function
alerts the driver when the vehicle might depart from its lane and provides assis-
tance by operating the steering wheel to keep the vehicle in its lane. Further-
more, the system also provides steering assistance when dynamic radar cruise
control with full-speed range is operat ing to keep the vehicle in its lane.
The LKA system recognizes visible
white or yellow lines with the camera
sensor on the upper portion of the
windshield.
LKA (Lane-Keeping Assist)
Summary of functions

2984-5. Using the driving support systems
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◆Lane departure alert function
When the system determines that
the vehicle might depart from its
lane, a warning is displayed on the
multi-information display, and either
the warning buzzer sounds or the
steering wheel vibrates to alert the
driver.
When the warning buzzer sounds or
the steering wheel vibrates, check
the surrounding road situation and
carefully operate the steering wheel
to move the vehicle back to the cen-
ter within the white (yellow) lines.
◆Steering assist function
When the system determines that
the vehicle might depart from its
lane, the system provides assistance
as necessary by operating the steer-
ing wheel in small amounts for a
short period of time to keep the
vehicle in its lane.
If the system detects that the steering
wheel has not been operated for a
fixed amount of time or the steering
wheel is not being firmly gripped, a
warning is displayed on the multi-
information display and the warning
buzzer sounds.
Functions included in LKA system

2994-5. Using the driving support systems
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Driving
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◆Vehicle sway warning
When the vehicle is swaying or
appears as if it may depart from its
lane multiple times, the warning
buzzer sounds and a message is dis-
played on the multi-information dis-
play to alert the driver.
◆Lane centering function
This function is linked with radar
cruise control and provides the
required assistance by operating the
steering wheel to keep the vehicle in
its current lane.
When radar cruise control is not
operating, the lane centering func-
tion does not operate.
If the system detects that the steering
wheel has not been operated for a
fixed amount of time or the steering
wheel is not being firmly gripped, a
warning is displayed on the multi-
information display and the warning
buzzer sounds.

3024-5. Using the driving support systems
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LKA indicator
The illumination condition of the
indicator informs the driver of the
system operation status.
Illuminated in white:
LKA system is operating.
Illuminated in green:
Steering wheel assistance of the steer-
ing assist function or lane centering
function is operating.
Flashing in amber:
Lane departure alert function is operat-
ing.
Operation display of steering wheel
operation support
Indicates that steering wheel assistance of the steering assist function or lane
centering function is operating.
Lane departure alert function display
Displayed when the multi-information disp lay is switched to the driving assist
system information screen.
Indications on the multi-information display
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Inside of displayed white lines is
whiteInside of displayed white lines is
black
Indicates that the system is recognizing
white (yellow) lines. When the vehicle
departs from its lane, the white line dis-
played on the side the vehicle departs
from flashes amber. Indicates that the system is not able to
recognize white (ye
llow) lines or is
temporarily canceled.

3034-5. Using the driving support systems
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■Operation conditions of each function
●Lane departure alert function
This function operates when all of the following conditions are met.
• LKA is turned on.
• Vehicle speed is approximatel y 32 mph (50 km/h) or more.
• System recognizes white (yellow) lines.
• Width of traffic lane is approx imately 9.8 ft. (3 m) or more.
• Turn signal lever is not operated.
• Vehicle is driven on a straight road or around a gentle curve with a radius of more
than approximately 492 ft. (150 m).
• No system malfunctions are detected. ( P. 660)
●Steering assist function
This function operates when all of the follo wing conditions are met in addition to the
operation conditions for the lane departure alert function.
• Setting for “Steering Assist” in of the multi-information display is set to “On”.
(  P. 108)
• Vehicle is not accelerated or dece lerated by a fixed amount or more.
• Steering wheel is not operated with a steering force level suitable for changing
lanes.
• ABS, VSC, TRAC and PCS are not operating.
• TRAC or VSC is not turned off.
●Vehicle sway warning
This function operates when all of the following conditions are met.
• Setting for “Sway Warning” in of the multi-information display is set to “On”.
(  P. 108)
• Vehicle speed is approximatel y 32 mph (50 km/h) or more.
• Width of traffic lane is approx imately 9.8 ft. (3 m) or more.
• No system malfunctions are detected. ( P. 660)
●Lane centering function
This function operates when all of the following conditions are met.
• LKA is turned on.
• Setting for “Lane Center” in of the mu lti-information display are set to “On”.
(  P. 108)
• System recognizes white (yellow) lines.
• Dynamic radar cruise control with full-speed range is operating.
• Width of traffic lane is approximately 8.2 to 13.5 ft. (2.5 to 4.1 m).
• Turn signal lever is not operated.
• Vehicle is driven on a straight road or around a gentle curve with a radius of more
than approximately 656 ft. (200 m).
• No system malfunctions are detected. ( P. 660)
• Vehicle does not accele rate or decelerate by a fixed amount or more.
• Steering wheel is not operated with a steering force level suitable for changing lanes.
• ABS, VSC, TRAC and PCS are not operating.
• TRAC or VSC is not turned off.
• Steering assist function is not operating.

3044-5. Using the driving support systems
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■Temporary cancellation of functions
When operation conditions are no longer met, a function may be temporarily canceled.
However, when the operation conditions are met again, operat ion of the function is auto-
matically restored. ( P. 303)
■Steering assist function/lane centering function
Depending on the vehicle speed, lane depart ure situation, road conditions, etc., the
operation of the functions may not be reco gnized or the functions may not operate.
■Lane departure alert function
The warning buzzer may be difficult to hear due to external noise, audio playback, etc.
Also, it may be difficult to f eel steering wheel vibrations due to the road conditions, etc.
■Hands off steering wheel alert
When the system determines that the driver has removed their hands from the steering
wheel while the steering assist function or lane centering function is operating, a warning
message is displayed on the multi-info rmation display and the buzzer sounds.
■White (yellow) lines are only on one side of road
The LKA system will not operate for the side on which white (yellow) lines could not be
recognized.

3184-5. Using the driving support systems
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●Motorcycles travelin g in the same lane
●When water or snow thrown up by the surrounding vehicles hinders the detecting of
the sensor
■Conditions under which the ve hicle-to-vehicle distance control mode may not function
correctly
In the case of the following conditions, o perate the brake pedal (or accelerator pedal,
depending on the situ ation) as necessary.
As the sensor may not be able to correctly detect vehicles ahead, the system may not
operate properly.
●When the vehicle ahead of you decelerates suddenly
●When your vehicle is pointing upwards
(caused by a heavy load in the luggage com-
partment, etc.)
●Preceding vehicle has an extremely high
ground clearance
●When the road curves or when the lanes are
narrow
●When steering wheel operation or your posi-
tion in the lane is unstable

3644-5. Using the driving support systems
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■Screen display
The parking assist monitor screen will be displayed if the shift position is
shifted to R while the power switch is in ON mode.
Intuitive parking assist
Rear Cross Traffic Alert (if
equipped)
A simplified image is displayed on
the upper part of the screen when an
obstacle is detected.
■Using the system
Use any of the following modes.
●Estimated course line display mode ( P. 366)
Estimated course lines are dis-
played which move in accor-
dance with the operation of the
steering wheel.
Using the Lexus parking assist monitor
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3654-5. Using the driving support systems
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Driving
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●Parking assist guide line display mode (P. 368)
The steering wheel return points
(parking assist guide lines) are
displayed.
●Distance guide line display mode
Distance guide lines only are dis-
played.
When the shift lever is in any position other than R, the display mode can be
changed in the following procedure. Press the “MENU” button on the Le xus Display Audio controller/Remote
Touch, and then select on the screen.
Select “Vehicle”, and then select “Backup Camera Guide Line Settings” on
the screen.
Select the desired display mode.
Estimated course line display
mode ( P. 366)
Parking assist guide line display
mode ( P. 368)
Distance guide line display mode
Distance guide lines only are dis-
played.
Switching the display mode
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3664-5. Using the driving support systems
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■Screen description Vehicle center guide line
The line indicates the estimated vehicle center on the ground.
Vehicle width guide line
The line indicates a guide path when the vehicle is being backed straight up.
The displayed width is wider th an the actual vehicle width.
The line aligns with the estimated course lines when the steering wheel is straight.
Estimated course lines
The lines show an estimated course when the steering wheel is turned.
Distance guide line
The line moves, together with the estimated course lines, in sync with the steering
wheel. The line shows points approximately 1.5 ft. (0.5 m) (red) and approximately
3 ft. (1 m) (yellow) from the center of the edge of the bumper.
Distance guide line
The line shows distance behind the vehicle, a point approximately 1.5 ft. (0.5 m)
(blue) from the edge of the bumper.
Estimated course line display mode
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