lane assist LEXUS RX450h 2021 User Guide

2334-5. Using the driving support systems
4
Driving
Inside of displayed white 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 mu lti-information dis-
play is switched to the driving assist system
information screen.
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 wh ite (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 ft. (3 m) or more.
• Turn signal lever is not operated. (Vehicle with BSM: Except when another vehicle
is in the lane on the side where the turn
signal was operated)
• Vehicle is not being driven around a sharp curve.
• No system malfunctions are detected. ( P.235)
*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 met in addition to the
operation conditions for the lane depar-
ture alert function.
• Setting for “Steering Assist” in of the multi-information display is set to “On”.
( P.88)
• Vehicle is not acceler ated 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.234)
●Vehicle sway warning function
This function operates when all of the fol-
lowing conditions are met.
• Setting for “Sway Warning” in of the multi-information display is set to “On”.
( P.88)
• 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.235)
●Lane centering function
This function operates when all of the fol-
D

2344-5. Using the driving support systems
lowing conditions are met.
• LTA is turned on.
• Setting for “Steering Assist” and “Lane Center” in of the multi-information
display are set to “On”. ( P.88)
• 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.235)
• Vehicle does not acc elerate 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.234)
• The vehicle is being driven in the center of a lane.
• Steering assist function is not operating.
■Temporary cancelation of functions
●When operation conditions 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 automa tically restored.
(  P.233)
●If the operation conditions ( P.233) 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. However, if the “Alert”
customization setting is set to ,
the system will notify the driver by vibrat-
ing the steering wheel instead of sound-
ing 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.
●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 sh own 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.

2354-5. Using the driving support systems
4
Driving
●When the system determines that the
driver is driving without holding the steer-
ing wheel while the system 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 cu rve while the lane
centering function is operating.
Depending on the vehicle condition and
road conditions, the warning may not
operate. Also, if the system 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 without holding the steer-
ing wheel while the st eering wheel assist
of the steering assist function is operat-
ing.
If the driver continue s 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 shown in the illustration
are simultaneously displayed on the
multi-information display. Depending on the vehicle and road condi-
tions, the warning may not operate.
■Warning message
If the following warning message is dis-
played on the multi-in formation display and
the LTA indicator illuminates in orange, fol-
low the appropriate troubleshooting proce-
dure. Also, if a different warning message is
displayed, follow the instructions displayed
on the screen.
●“LTA Malfunction Visit Your Dealer”
The system may not be operating properly.
Have the vehicle inspected by your Lexus
dealer.
●“LTA Unavailable”
The system is temporarily canceled due to
a malfunction in a sensor other than the
front camera. Turn the LTA system off, wait
for a little while, and then turn the LTA sys-
tem back on.
●“LTA Unavailable at Current Speed”
The function cannot be used as the vehicle
speed exceeds the LTA operation range.
Drive slower.
■Customization
Function settings can be changed. (Cus-
tomizable features: P.480)

2474-5. Using the driving support systems
4
Driving
●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
●While the vehicle speed is decreasing to
the set speed after the vehicle acceler-
ates by depressing the accelerator pedal
*: If equipped
Meter control switches
Turning the Blind Spot Monitor on/off.
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 drive 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 re liance could lead to
an accident resulting in death or serious
injury.
As the system may not function correctly
under certain conditio ns, the driver’s own
visual confirmation of safety is necessary.
System components
A

2534-5. Using the driving support systems
4
Driving
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)
Ultrasonic sensors are used to detect
static objects in the detection area
when driving at a low speed or backing
up. ( P.255)
■RCTA (Rear Cross Traffic Alert)
function (if equipped)
Rear side radar sensors are used to
detect approaching vehicles in the
detection areas behind the vehicle
when backing up. ( P.261)
■Adjusting the buzzer volume
The buzzer volume can be adjusted on
the multi-information display. The vol-
ume of buzzers for the intuitive parking
assist and RCTA function will be
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 or such
as a wall is high, a warning operates
to urge the driver to take evasive
action.
PKSA (Parking Support Alert)
system
Setting the buzzer volume

2864-5. Using the driving support systems
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard also after
the vehicle comes to a stop.
■ECB operating sound
ECB operating sound may be heard in the
following cases, but it does not indicate that
a malfunction has occurred.
●Operating sound heard from the engine
compartment when the brake pedal is
operated.
●Motor sound of the brake system heard
from the front part of the vehicle when
the driver’s door is opened.
●Operating sound heard from the engine
compartment when one or two minutes
passed after the stop of the hybrid sys-
tem.
■Active Cornering Assist operation
sounds and vibrations
When the Active Cornering Assist is oper-
ated, operation sounds and vibrations may
be generated from the brake system, but
this is not a malfunction.
■EPS operation sound
When the steering wheel is operated, a
motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
■Reduced effectiveness of the EPS sys-
tem
The effectiveness of the EPS system is
reduced to prevent the system from over-
heating when there is frequent steering
input over an extended period of time. The
steering wheel may feel heavy as a result.
Should this occur, re frain from excessive
steering input or stop the vehicle and turn
the hybrid system off. The EPS system
should return to normal within 10 minutes.
■Automatic reactivation of TRAC, Trailer
Sway Control and VSC systems
After turning the TRAC, Trailer Sway Con-
trol and VSC systems off, the systems will
be automatically re-enabled in the following
situations:
●When the power switch is turned off
●If only the TRAC system is turned off, the TRAC will turn on when vehicle speed
increases
If both the TRAC and VSC systems are
turned off, automatic re-enabling will not
occur when vehicle speed increases.
■Operating conditions of Active Corner-
ing Assist
The system operates when the following
occurs.
●TRAC/VSC can operate
●The driver is attempting to accelerate
while turning
●The system detects that the vehicle is
drifting to the outer side
●The brake pedal is released
■Secondary Collision Brake operating
conditions
The system operates when the SRS airbag
sensor detects a collision while the vehicle
is in motion.
However, the system does not operate in
any of the following situations.
●The vehicle speed is below 6 mph (10
km/h)
●Components are damaged
■Secondary Collision Brake automatic
cancellation
The system is automatically canceled in any
of the following situations.
●The vehicle speed drops below approxi-
mately 6 mph (10 km/h)
●A certain amount of time elapses during
operation
●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.

2914-6. Driving tips
4
Driving
Use fluids that are appropriate to
the prevailing outside temperatures.
•Engine oil
• Engine/power control unit coolant
•Washer fluid
Have a service technician inspect
the condition of the 12-volt battery.
 Have the vehicle fitted with four
snow tires or purchase a set of tire
chains for the front tires.
Ensure that all tires ar e of the specified size
and the same brand, and that chains match
the size of the tires.
Perform the following according to the
driving conditions:
 Do not try to forcibly open a window
or move a wiper that is frozen. Pour
warm water over the frozen area to
melt the ice. Wipe away the water
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.
Pre-winter preparations
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
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 the LTA (Lane Tracing
Assist) system.
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow
tires from your Lexus dealer 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

4227-2. Steps to take in an emergency
■Rear passengers’ seat belt reminder light*1 (warning buzzer)*2
*1: This light illuminates on the center panel.Regardless of whether or not a rear passenger is present, if the power switch is turned to
ON mode with the rear seat belts unfastened, this light will also illuminate for a certain
period of time.
*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)
Warning lightDetails/Actions
(RX450h)
or
(RX450hL)
Warns the rear passengers to fasten their seat belts
 Fasten the seat belt.
Warning lightDetails/Actions
Indicates the following:
Low tire pressure due to flat tire;
 Low tire pressure due to natural causes; or
 The tire pressure warning system is malfunctioning
 Immediately stop the vehicle in a safe place.
Handling method ( P.425)
Warning lightDetails/Actions
(orange)
Indicates a malfunction in th e LTA (Lane Tracing Assist)
 Follow the instructions displayed on the multi-information display.
(  P.235)

4307-2. Steps to take in an emergency
not be charged when the shift lever is in N,
shift the shift lever to P when the vehicle is
stopped.
■If “Traction Battery Needs to be Pro-
tected. Shift into P to Restart.” is dis-
played
This message is displayed when the hybrid
battery (traction battery) charge has
become extremely low because the shift
lever has been left in N for a certain amount
of time.
When operating the vehicle, shift to P and
restart the hybrid system.
■If “Shift Is in N Release Accelerator
Before Shifting” is displayed
Message is displayed when the accelerator
pedal has been depressed and the shift
lever is in N.
Release the accelerator pedal and shift the
shift lever to D or R.
■If “Depress Brake when Vehicle Is
Stopped Hybrid Syst em May Overheat”
is displayed
Message is displayed when the accelerator
pedal is depressed to maintain the vehicle
position when stopped on a upward slope,
etc.
If this continues, th e hybrid system may
overheat.
Release the accelerator pedal and depress
the brake pedal.
■If “Power Turned Off to Save Battery” is
displayed
This message is displayed when the power
was cut off due to the automatic power off
function. The next time the hybrid system is
started, increase the engine speed slightly
and maintain it at that speed for approxi-
mately 5 minutes to recharge the 12-volt
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
●AFS (Adaptive Front-lighting System) (if equipped)
●The automatic headlight leveling system
●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 re solved. (causes and coping
methods: P.218)
■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.218, 424)
●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 “Maintenance Required Soon” is dis-
played (U.S.A. only)
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.362)
*: 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 (U.S.A. only)
Indicates that all mainte nance is required to
correspond to the driven distance on the

4437-2. Steps to take in an emergency
7
When trouble arises
WARNING
• PCS (Pre-Collision System)
• LTA (Lane Tracing Assist)
• RSA (Road Sign Assist) (if equipped)
•Automatic High Beam
• AFS (Adaptive Front-lighting System) (if equipped)
• Tire pressure warning system
• Intuitive parking assist (if equipped)
• PKSB (Parking Support Brake) (if equipped)
• Lexus parking assist monitor (if equipped)
• Panoramic view monitor (if equipped)
• BSM (Blind Spot Monitor) (if equipped)
• Navigation system (if equipped)
Also, not only can the following system
not be utilized fully, but it may even nega-
tively affect the drive-train components:
•E-Four
■Speed limit when using the compact
spare tire
Do not drive at speeds in excess of 50
mph (80 km/h) when a compact spare
tire is installed on the vehicle.
The compact spare tire is not designed
for driving at high speeds. Failure to
observe this precaution may lead to an
accident causing deat h or serious injury.
■After using the tools and jack
Before driving, make sure all the tools
and jack are securely in place in their
storage location to reduce the possibility
of personal injury during a collision or
sudden braking.
NOTICE
■Be careful when driving over bumps
with the compact spare tire installed
on the vehicle
The vehicle becomes lower when driving
with the compact spar e tire compared to
when driving with standard tires. Be
careful when driving over uneven road
surfaces.
■Driving with tire chains and the com-
pact spare tire
Do not fit tire chains to the compact
spare tire. Tire chains may damage the
vehicle body and adversely affect driving
performance.
■When replacing the tires
When removing or fitting the wheels,
tires or the tire pr essure warning valve
and transmitter, contact your Lexus
dealer as the tire pressure warning valve
and transmitter may be damaged if not
handled correctly.
■When stowing the flat tire
(RX450hL)
●Ensure that there is no object caught
between the tire and the vehicle
underbody.
●Securely tighten the spare tire clamp
bolt to hold the spare wheel carrier by
the hook.
●Stow the flat tire in the spare tire loca-
tion. Failure to do so may cause dam-
age to the spare tire carrier. Proper
storage reduces the possibility of injury
in a collision or during sudden braking.
●Have the flat tire repaired and the
spare tire replaced with it as soon as
possible.