steering Lexus IS350 2021 / LEXUS 2021 IS 300, IS 350 (OM53E98U) Service Manual

1834-5. Using the driving support systems
4
Driving
■Lane departure alert function
When the system determines that the
vehicle might depart from its lane or
course
*, a warning is displayed on the
multi-information display, and either a
warning buzzer will sound or the steer-
ing wheel will vibrate to alert the driver.
When the warning buzzer sounds or the
steering wheel vibrates, check the area
around your vehicle and carefully operate
the steering wheel to move the vehicle
back to the center of the lane.
Vehicle with BSM: When the system deter-
mines that the vehicle might depart from its
lane and that the po ssibility of a collision
with an overtaking vehicle in the adjacent
lane is high, the lane departure alert will
operate even if the turn signals are operat-
ing.
*: Boundary between asphalt and the side of the road, such as grass, soil, or a curb
WARNING
●Light from the headlights of an oncom-
ing vehicle, the sun, etc. enters the
camera.
●The vehicle is driven on a slope.
●The vehicle is driven on a road which
tilts left or right, or a winding road.
●The vehicle is driven on an unpaved or
rough road.
●The traffic lane is excessively narrow
or wide.
●The vehicle is extremely tilted due to
carrying heavy luggage or having
improper tire pressure.
●The distance to the preceding vehicle
is extremely short.
●The vehicle is moving up and down a
large amount due to road conditions
during driving (poor roads or road
seams).
●When driving in a tunnel or at night
with the headlights off or when a head-
light is dim due to its lens being dirty or
it being misaligned.
●The vehicle is struck by a crosswind.
●The vehicle is affected by wind from a
vehicle driven in a nearby lane.
●The vehicle has just changed lanes or
crossed an intersection.
●Tires which differ by structure, manu-
facturer, brand or tread pattern are
used.
●When tires of a size other than speci-
fied are installed.
●Snow tires, etc. are equipped.
●The vehicle is being driven at
extremely high speeds.
Functions included in LTA system

1844-5. Using the driving support systems
■Steering assist function
When the system determines that the
vehicle might depart from its lane or
course
*, the system provides assis-
tance as necessary by operating the
steering wheel in small amounts for a
short period of time to keep the vehicle
in its lane.
Vehicle with BSM: When the system deter-
mines that the vehicle might depart from its
lane and that the possibility of a collision
with an overtaking vehicle in the adjacent
lane is high, the steeri ng assist function will
operate even if the turn signals are operat-
ing.
*: Boundary between asphalt and the side of the road, such as grass, soil, or a curb
■Vehicle sway warning function
When the vehicle is swaying within a
lane, the warning buzzer will sound and
a message will be displayed on the
multi-information display to alert the
driver.
■Lane centering function
This function is linked with dynamic
radar cruise control with full-speed
range and provides the required assis-
tance by operating the steering wheel
to keep the vehicle in its current lane.
When dynamic radar cruise control with
full-speed range is not operating, the lane
centering function does not operate.
In situations where the white (yellow) lane
lines are difficult to see or are not visible,
such as when in a traffic jam, this function
will operate to help follow a preceding
vehicle by monitoring the position of the
preceding vehicle.

1854-5. Using the driving support systems
4
Driving
Press the LTA switch to turn the LTA
system on.
The LTA indicator illuminates and a mes-
sage is displayed on the multi-information
display.
Press the LTA switch again to turn the LTA
system off.
When the LTA system is turned on or off,
operation of the LTA system continues in
the same condition the next time the
engine is started.
LTA indicator
The illumination condition of the indicator
informs the driver of the system operation
status.
Illuminated in white: LTA system is operat-
ing.
Illuminated in green: Steering wheel assis-
tance of the steering assist function or lane
centering function is operating.
Flashing in orange: Lane departure alert
function is operating.
Operation display of steering
wheel operation support
Displayed when the multi-information dis-
play is switched to the driving support sys-
tem information display.
Turning LTA system on
Indications on multi-information
display
A
B

1864-5. Using the driving support systems
Indicates that steering wheel assistance of
the steering assist function or lane center-
ing function is operating.
Both outer sides of the lane are displayed:
Indicates that steering wheel assist of the
lane centering function is operating.
One outer side of the lane is displayed:
Indicates that steering wheel assist of the
steering assist function is operating.
Both outer sides of the lane are flashing:
Alerts the driver that their input is neces-
sary to stay in the center of the lane (lane
centering function).
Lane departure alert function dis-
play
Displayed when the mu lti-information dis-
play is switched to the driving support sys-
tem informat ion display.
Inside of displayed lines is white
Indicates that the system is recognizing
white (yellow) lines or a course
*. When
the vehicle departs from its lane, the
white line displayed on the side the
vehicle departs from flashes orange.
Inside of displayed lines is black
Indicates that the system is not able to
recognize white (yellow) lines or a
course
* or is temporarily canceled.
*: Boundary between asphalt and the side of the road, such as grass, soil, or a curb
Follow-up cruising display
Displayed when the multi-information dis-
play is switched to the driving support sys-
tem information display.
Indicates that steering assist of the lane
centering function is operating by monitor-
ing the position of a preceding vehicle.
When the follow-up cruising display is dis-
played, if the preceding vehicle moves,
your vehicle may move in the same way.
Always pay careful attention to your sur-
roundings and operate the steering wheel
as necessary to correct the path of the
vehicle and ensure safety.
■Operation conditions of each function
●Lane departure alert function
This function operates when all of the fol-
lowing conditions are met.
• LTA is turned on.
• Vehicle speed is approximately 32 mph (50 km/h) or more.
*1
• System recognizes white (yellow) lane lines or a course*2. (When a white [yel-
low] line or course*2 is recognized on
only one side, the system will operate
only for the recognized side.)
• Width of traffic lane is approximately 9.8
C
D

1874-5. Using the driving support systems
4
Driving
ft. (3 m) or more.
• Turn signal lever is not operated. (Vehicle with BSM: Except when another vehicle
is in the lane on th e side where the turn
signal was operated)
• Vehicle is not being driven around a
sharp curve.
• No system malfunctions are detected. ( P.189)
*1: The function operates even if the vehi-
cle speed is less than approximately 32
mph (50 km/h) when the lane center-
ing function is operating.
*2: Boundary between asphalt and the side of the road, such as grass, soil, or a curb
●Steering assist function
This function operates when all of the fol-
lowing conditions are me t in addition to the
operation conditions for the lane depar-
ture alert function.
• Vehicle is not accelerated or decelerated
by a fixed amount or more.
• Steering wheel is not operated with a
steering force level su itable for changing
lanes.
• ABS, VSC, TRAC and PCS are not oper-
ating.
• TRAC or VSC is not turned off.
• Hands off steering wheel warning is not displayed. ( P.188)
●Vehicle sway warning function
This function operates when all of the fol-
lowing conditions are met.
• Setting for “Warning” in of the multi-information display is set to “On”.
( P.76)
• Vehicle speed is approximately 32 mph
(50 km/h) or more.
• Width of traffic lane is approximately 9.8
ft. (3 m) or more.
• No system malfunctions are detected.
( P.189)
●Lane centering function
This function operates when all of the fol-
lowing conditions are met.
• LTA is turned on.
• Setting for “Lane Center” in of the multi-information display are set to “On”.
( P.76) • This function recognizes white (yellow)
lane lines or the position of a preceding
vehicle (except when the preceding vehi-
cle is small, such as a motorcycle).
• The dynamic radar cruise control with full-speed range is operating in vehi-
cle-to-vehicle distance control mode.
• Width of traffic lane is approximately 10
to 13 ft. (3 to 4 m).
• Turn signal lever is not operated.
• Vehicle is not being driven around a sharp curve.
• No system malfunctions are detected. ( P.189)
• Vehicle does not ac celerate or deceler-
ate by a fixed amount or more.
• Steering wheel is not operated with a steering force level su itable for changing
lanes.
• ABS, VSC, TRAC and PCS are not oper- ating.
• TRAC or VSC is not turned off.
• Hands off steering wheel warning is not displayed. ( P.188)
• The vehicle is being driven in the center of a lane.
• Steering assist function is not operating.
■Temporary cancelation of functions
●When operation condit ions are no longer
met, a function may be temporarily can-
celed. However, when the operation con-
ditions are met again, operation of the
function is automatically restored.
(  P.186)
●If the operation conditions ( P.186) are
no longer met while the lane centering
function is operating, the steering wheel
may vibrate and the buzzer may sound to
indicate that the function has been tem-
porarily canceled. Howe ver, if the “Alert”
customization setting is set to , the
system will notify the driver by vibrating
the steering wheel instead of sounding
the buzzer.
■Steering assist function/lane centering
function
●Depending on the vehicle speed, lane
departure situation, road conditions, etc.,
the driver may not feel the function is
operating or the function may not oper-
ate at all.

1884-5. Using the driving support systems
●The steering control of the function is
overridden by the driver’s steering wheel
operation.
●Do not attempt to test the operation of
the steering assist function.
■Lane departure alert function
●The warning buzzer may be difficult to
hear due to external noise, audio play-
back, etc. Also, it may be difficult to feel
steering wheel vibrations due to the road
conditions, etc.
●If the edge of the course* is not clear or
straight, the lane departure alert function
may not operate.
●Vehicle with BSM: It may not be possible
for the system to determine if there is a
danger of a collision with a vehicle in an
adjacent lane.
●Do not attempt to test the operation of
the lane departure alert function.
*: Boundary between asphalt and the side
of the road, such as grass, soil, or a curb
■Hands off steering wheel warning
In the following situations, a warning mes-
sage urging the driver to hold the steering
wheel and the symbol shown in the illustra-
tion are displayed on the multi-information
display to warn the driver. The warning
stops when the system determines that the
driver holds the steering wheel. Always
keep your hands on the steering wheel
when using this system, regardless of warn-
ings.
●When the system determines the driver is
not holding the steeri ng wheel while the
lane centering function is operating.
If the driver continue s to keep their hands
off of the steering wheel, the buzzer
sounds, the driver is warned and the func- tion is temporarily ca
nceled. This warning
also operates in the same way when the
driver continuously operates the steering
wheel only a small amount.
The buzzer also sounds even if the alert
type is set to .
●When the system determines that the
vehicle may deviate from the lane while
driving around a curve while the lane
centering function is operating.
Depending on the vehicle condition and
road conditions, the warning may not
operate. Also, if the sy stem determines that
the vehicle is driving around a curve, warn-
ings will occur earlier than during
straight-lane driving.
●When the system determines that the
driver is driving with out holding the steer-
ing wheel while the st eering wheel assist
of the steering assist function is operat-
ing.
If the driver continues to keep their hands
off of the steering wheel and the steering
wheel assist is operating, the buzzer
sounds and the driver is warned. Each time
the buzzer sounds, the continuing time of
the buzzer becomes longer.
The buzzer also sounds even if the alert
type is set to .
■Vehicle sway warning function
When the system determines that the vehi-
cle is swaying while the vehicle sway warn-
ing function is operating, a buzzer sounds
and a warning message urging the driver to
rest and the symbol sh own in the illustration
are simultaneously displayed on the
multi-information display.

1954-5. Using the driving support systems
4
Driving
the location of the steering wheel in the vehicle (left side driver position versus right side
driver position.) If the vehicle is driven to a re gion where the overtaking lane is on a different
side from where the vehicle is normally driven, the vehicle may accelerate when the turn
signal lever is operated in the opposite direction to the overtaking lane (e.g., if the driver
normally operates the vehicle in a region where the overtaking lane is to the right but then
drives to a region where the overtaking lane is to the left, the vehicle may accelerate when
the right turn signal is activated).
Example of acceleration
When there are no longer any preceding vehicles driving slower than the set
speed
The system accelerates until the set speed is re ached. The system then returns to constant
speed cruising.
1 Press the “ON/OFF” button to acti-
vate the cruise control.
Dynamic radar cruise control indicator will
come on and a message will be displayed
on the multi-information display. Press the
button again to deactivate the cruise con-
trol.
If the “ON/OFF” button is pressed and
held for 1.5 seconds or more, the system
turns on in constant speed control mode.
( P.199)
2 Accelerate or decelerate, with
accelerator pedal operation, to the
desired vehicle speed (at or above
approximately 20 mph [30 km/h]) and push the lever down to set the
speed.
Cruise control “SET”
indicator will come
on.
The vehicle speed at the moment the lever
is released beco mes the set speed.
Adjusting the set speed by the lever
To change the set speed, operate the
lever until the desired set speed is dis-
played.
C
Setting the vehicle speed (vehi-
cle-to-vehicle distance control
mode)
Adjusting the set speed

1984-5. Using the driving support systems
An example of this would be if another
driver cuts in front of you while you are
following a vehicle. Depress the brake
pedal to ensure an appropriate vehi-
cle-to-vehicle distance.
■Warnings may not occur when
In the following instances, warnings
may not occur even when the vehi-
cle-to-vehicle distance is small.
 When the speed of the preceding
vehicle matches or exceeds your
vehicle speed
 When the preceding vehicle is trav-
eling at an extremely slow speed
 Immediately after the cruise control
speed was set
 When depressing the accelerator
pedal
While driving in vehicle-to-vehicle dis-
tance control mode, this function will
reduce the vehicle speed, if it is deter-
mined to be necessary.
■Function operation
When the steering wheel begins to be
turned, the vehicle speed will begin
being reduced. When the steering wheel is returned to the center posi-
tion, the vehicle speed reduction will
end.
Depending on the situation, the vehicle
speed will then return to the vehi-
cle-to-vehicle distance control mode
set speed.
In situations where vehicle-to-vehicle
distance control needs to operate,
such as when a preceding vehicle cuts
in front of your vehicle, the curve speed
reduction function will be canceled.
■Operation display
Displayed when the vehicle speed is
being reduced.
When the vehicle speed reduction ends,
the display will disappear.
■Changing the settings of the curve
speed reduction function
The curve speed reduction function
can be enabled/disabled and the vehi-
cle speed reduction strength can be
adjusted.
Press the or meter control
switch to select . Press or
to select “Curve Speed Reduction” and
then press .
The setting will chan ge each time the
Curve speed reduction function

2014-5. Using the driving support systems
4
Driving
●Motorcycles traveling in the same lane
●When water or snow thrown up by the
surrounding vehicles hinders the detect-
ing of the sensor
●When your vehicle is pointing upwards
(caused by a heavy load in the luggage
compartment, etc.)
●Preceding vehicle has an extremely high
ground clearance
■Conditions under which the vehi-
cle-to-vehicle distance control mode
may not function correctly
In the case of the following conditions,
operate the brake pedal (or accelerator
pedal, depending on the situation) as nec-
essary.
As the sensor may not be able to correctly
detect vehicles ahead, the system may not
operate properly.
●When the road curves or when the lanes
are narrow
●When steering wheel operation or your
position in the lane is unstable
●When the vehicle ahead of you deceler-
ates suddenly
●When driving on a road surrounded by a
structure, such as in a tunnel or on a
bridge
■Situations in which the curve speed
reduction function may not operate
properly
In situations such as the following, the curve
speed reduction function may not operate
properly:
●When the vehicle is being driven around
a curve on an incline/decline
●When the course of the vehicle differs
from the shape of the curve
●When the vehicle speed is excessively
high when entering a curve
●When the steering wheel is suddenly
operated

2364-5. Using the driving support systems
Vehicles without Adaptive Variable
Suspension SystemExcept F SPORT models
F SPORT models
1 Normal mode
Provides an optimal ba lance of fuel econ-
omy, quietness, and dynamic performance.
Suitable for city driving.
Press the switch to change the driving
mode to normal mode when Eco drive
mode or sport mode is selected.
2 Eco drive mode
Helps the driver accelerate in an
eco-friendly manner and improve fuel
economy through moderate throttle char-
acteristics and by controlling the operation of the air conditioning system (heat-
ing/cooling).
When not in Eco drive mode, if the driving
mode select switch is
turned to the left, the
Eco drive mode indicator will come on.
3 Sport mode
Controls the transmission and engine to
provide quick, powerful acceleration. This
mode also changes the steering feel, mak-
ing it suitable for when agile driving
response is desired, such as when driving
on roads with many curves.
When not in sport mode, if the driving
mode select switch is turned to the right,
the “SPORT” indicator will comes on.
Vehicles with Adaptive Variable
Suspension System
1 Normal mode/Customized mode
Normal mode and customized mode are
selected by pressing the driving mode
select switch. Each time the switch is
pressed, the driving mode changes
between normal mode and customized
mode. When customized mode is
Driving mode select switch
The driving modes can be selected
to suit driving condition.
Selecting a drive mode
A
B