lane assist Lexus IS350 2021 / LEXUS 2021 IS 300, IS 350 (OM53E98U) User Guide

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.

2024-5. Using the driving support systems
*:If equipped
Meter control switches
Turning the Blind Spot Monitor on/off.
Outside rear view mirror indicators
When a vehicle is detected in a blind spot
of the outside rear view mirrors or
approaching rapidly from behind into a
blind spot, the outside rear view mirror
indicator on the detected side will illumi-
nate. If the turn signal lever is operated
toward the detected side, the outside rear
view mirror indicator flashes.
■Outside rear view mirror indicator visi-
bility
In strong sunlight, the outside rear view mir-
ror indicator may be difficult to see.
■When “Blind Spot Monitor Unavailable”
is shown on the multi-information dis-
play
Ice, snow, mud, etc., may be attached to the
rear bumper around the sensors. ( P.204)
The system should return to normal opera-
tion after removing the ice, snow, mud, etc.
from the rear bumper. Additionally, the sen-
sors may not operate normally when driving
in extremely hot or cold environments.
■Customization
Some functions can be customized.
(  P.394)
BSM (Blind Spot Monitor)*
The Blind Spot Monitor is a system
that uses rear side radar sensors
installed on the inner side of the
rear bumper on the left and right
side to assist the driver in confirm-
ing safety when changing lanes.
WARNING
■Cautions regarding the use of the sys-
tem
The driver is solely responsible for safe
driving. Always driv e safely, taking care
to observe your surroundings.
The Blind Spot Monitor is a supplemen-
tary function which alerts the driver that a
vehicle is in a blind spot of the outside
rear view mirrors or is approaching rap-
idly from behind into a blind spot. Do not
overly rely on the Blind Spot Monitor. As
the function cannot judge if it is safe to
change lanes, over reliance could lead to
an accident resulting in death or serious
injury.
As the system may not function correctly
under certain conditions, the driver’s own
visual confirmation of safety is necessary.
System components
A
B

2084-5. Using the driving support systems
ations:
• When the sensor is misaligned due to a strong impact to the sensor or its sur-
rounding area
• When the distance between your vehicle and a guardrail, wall, etc. that enters the
detection area is short
• When driving up an d down consecutive
steep inclines, such as hills, dips in the
road, etc.
• When vehicle lanes are narrow, or when driving on the edge of a lane, and a vehi-
cle traveling in a lane other than the adja-
cent lanes enters the detection area
• When driving on roads with sharp bends,
consecutive curves, or uneven surfaces
• When the tires are slipping or spinning
• When the distance between your vehicle and a following vehicle is short
• When an accessory (such as a bicycle carrier) is installed to the rear of the vehi-
cle
*: If equipped
■Intuitive parking assist (if
equipped)
 P.210
■RCTA (Rear Cross Traffic Alert)
function (if equipped)
 P.216
PKSA (Parking Support
Alert)*
The Parking Support Alert system
consists of the following functions
that operate when driving at a low
speed or backing up, such as when
parking. When the system deter-
mines that the possibility of a colli-
sion with a detected object, such as
a wall is high, a warning operates to
urge the driver to take evasive
action.
PKSA (Parking Support Alert)
system

2414-5. Using the driving support systems
4
Driving
●The accelerator pedal is depressed a
large amount
WARNING
■The ABS does not operate effectively
when
●The limits of tire gripping performance
have been exceeded (such as exces-
sively worn tires on a snow covered
road).
●The vehicle hydroplanes while driving
at high speed on wet or slick roads.
■Stopping distance when the ABS is
operating may exceed that of normal
conditions
The ABS is not designed to shorten the
vehicle’s stopping di stance. Always main-
tain a safe distance from the vehicle in
front of you, especially in the following
situations:
●When driving on dirt, gravel or
snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes
or uneven surfaces
■TRAC/VSC may not operate effec-
tively when
Directional control and power may not
be achievable while driving on slippery
road surfaces, even if the TRAC/VSC
system is operating. Drive the vehicle
carefully in conditions where stability and
power may be lost.
■Active Cornering Assist does not
operate effectively when
●Do not overly rely on Active Corner-
ing Assist. Active Cornering Assist
may not operate effectively when
accelerating down slopes or driving on
slippery road surfaces.
●When Active Cornering Assist fre-
quently operates, Active Cornering
Assist may temporarily stop operating
to ensure proper operation of the
brakes, TRAC and VSC.
■Hill-start assist control does not oper-
ate effectively when
●Do not overly rely on hill-start assist
control. Hill-start assist control may
not operate effectively on steep
inclines and roads covered with ice.
●Unlike the parking brake, hill-start
assist control is not intended to hold
the vehicle stationary for an extended
period of time. Do not attempt to use
hill-start assist control to hold the vehi-
cle on an incline, as doing so may lead
to an accident.
■When the TRAC/VSC is activated
The slip indicator light flashes. Always
drive carefully. Reckless driving may
cause an accident. Exercise particular
care when the indicator light flashes.
■When the TRAC/VSC systems are
turned off
Be especially careful and drive at a speed
appropriate to the road conditions. As
these are the systems to help ensure
vehicle stability and driving force, do not
turn the TRAC/VSC systems off unless
necessary.
■Replacing tires
Make sure that all ti res are of the speci-
fied size, brand, tread pattern and total
load capacity. In addition, make sure that
the tires are inflated to the recom-
mended tire inflation pressure level.
The ABS, TRAC and VSC systems will
not function correctly if different tires are
installed on the vehicle.
Contact your Lexus dealer for further
information when replacing tires or
wheels.

2434-6. Driving tips
4
Driving
4-6.Driving tips
Use fluids that are appropriate to
the prevailing outside temperatures.
•Engine oil
• Engine coolant
•Washer fluid
Have a service technician inspect
the condition of the battery.
 Have the vehicle fitted with four
snow tires or purchase a set of tire
chains for the rear tires.
*
Ensure that all tires are the specified size
and brand, and that chains match the size
of the tires.
*: Tire chains cannot be mounted on vehi-
cles with front and rear tires of differing
sizes.
Perform the following according to the
driving conditions:
 Do not try to forcibly open a window
Winter driving tips
Carry out the necessary prepara-
tions and inspections before driving
the vehicle in winter. Always drive
the vehicle in a manner appropriate
to the prevailing weather condi-
tions.
Preparation for winter
WARNING
■Driving with snow tires
Observe the following precautions to
reduce the risk of accidents.
Failure to do so may result in a loss of
vehicle control and cause death or seri-
ous injury.
●Use tires of the specified size.
●Maintain the recommended level of air
pressure.
●Do not drive in excess of 75 mph (120
km/h), regardless of the type of snow
tires being used.
●Use snow tires on all, not just some
wheels.
■Driving with tire chains (vehicles with
front and rear tires of the same size)
Observe the following precautions to
reduce the risk of accidents.
Failure to do so may result in the vehicle
being unable to be driven safely, and may
cause death or serious injury.
●Do not drive in excess of the speed
limit specified for the tire chains being
used, or 30 mph (50 km/h), which-
ever is lower.
●Avoid driving on bumpy road surfaces
or over potholes.
●Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.
●Slow down sufficiently before entering
a curve to ensure that vehicle control is
maintained.
●Do not use LTA (Lane Tracing Assist)
system.
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow
tires from Lexus dealers or legitimate tire
retailers.
This is because the removal and attach-
ment of snow tires affects the operation
of the tire pressure warning valves and
transmitters.
Before driving the vehicle

3417-2. Steps to take in an emergency
7
When trouble arises
*1: This light illuminates on the center panel.
*2: Rear passengers’ seat belt warning buzzer:
The rear passengers’ seat belt warning buzzer sounds to alert the rear passenger that his or
her seat belt is not fastened. If the seat belt is unfastened, the buzzer sounds intermittently
for a certain period of time, af ter the seat belt is fastened and unfastened and the vehicle
reaches a certain speed.
■Tire pressure warning light
■LTA indicator (warning buzzer)
■Intuitive parking assist OFF indicator (warning buzzer)
Warning lightDetails/Actions
When the light comes on after blinking for approximately 1 minute:
Malfunction in the tire pressure warning system
 Have the system checked by your Lexus dealer.
When the light comes on:
Low tire inflation pressure such as
 Natural causes
 Flat tire
 Immediately stop the vehicle in a safe place.
Handling method ( P.344)
Warning lightDetails/Actions
(orange)
Indicates a malfunction in th e LTA (Lane Tracing Assist)
 Follow the instructions displayed on the multi-information display.
(  P.189)
Warning lightDetails/Actions
(flashes)
(if equipped)
Indicates a malfunction in the in tuitive parking assist function
 Have the vehicle inspected by your Lexus dealer immediately.
Indicates that the system is temporarily unavailable, possibly due to a
sensor being dirty or covered with ice, etc.
 Follow the instructions displayed on the multi-information display.
(  P.212)

3477-2. Steps to take in an emergency
7
When trouble arises
■If “Engine Stopped Steering Power
Low” is displayed
This message is displa yed if the engine is
stopped while driving.
When steering wheel operations are
heavier than usual, grip the steering wheel
firmly and operate it using more force than
usual.
■If “Auto Power Off to Conserve Battery”
is displayed
Power was turned off due to the automatic
power off function. Next time when starting
the engine, increase the engine speed
slightly and maintain that level for approxi-
mately 5 minutes to recharge the battery.
■If “Headlight System Malfunction Visit
Your Dealer” is displayed
The following systems may be malfunction-
ing. Have the vehicle inspected by your
Lexus dealer immediately.
●The LED headlight system
●The automatic headlight leveling system
(if equipped)
●Automatic High Beam
■If “Radar Cruise Control Unavailable
See Owner's Manual” is displayed
The dynamic radar cruise control with
full-speed range system is suspended tem-
porarily or until the problem shown in the
message is resolved. (causes and coping
methods: P.168)
■If “Radar Cruise Control Unavailable” is
displayed
The dynamic radar cruise control with
full-speed range system cannot be used
temporarily. Use the system when it
becomes available again.
■If a message that indicates the malfunc-
tion of front camera is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.168, 337)
●PCS (Pre-Collision system)
●LTA (Lane Tracing Assist)
●Automatic High Beam
●RSA (Road Sign Assist) (if equipped)
●Dynamic radar cruise control with
full-speed range
■If a message that indicates the malfunc-
tion of radar sensor is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.168, 337)
●PCS (Pre-Collision system)
●LTA (Lane Tracing Assist)
●Dynamic radar cruise control with
full-speed range
■If “Maintenance Required Soon” is dis-
played
Indicates that all maintenance according to
the driven distance on the maintenance
schedule
* should be performed soon.
Comes on approximately 4500 miles
(7200 km) after the message has been
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. ( P.286)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed
Indicates that all mainte nance is required to
correspond to the driven distance on the
maintenance schedule
*.
Comes on approximately 5000 miles
(8000 km) after the message has been
reset. (The indicator will not work properly
unless the message ha s been reset.) Per-
form the necessary maintenance. Please
reset the message after the maintenance is
performed. ( P.286)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil should be
scheduled to be changed.