brakes LEXUS RX450h 2021 User Guide

1814-1. Before driving
4
Driving
cle-trailer speed limit is 65 mph
(104 km/h) on a flat, straight, dry
road. Do not exceed this limit, the
posted towing speed limit or the
speed limit for your trailer as set
forth in your trailer owner’s manual,
whichever is lowest. Instability of the
towing vehicle-trailer combination
(trailer sway) increases as speed
increases. Exceeding speed limits
may cause loss of control.
 Before starting out, check the trailer
lights, tires and the vehicle-trailer
connections. Recheck after driving
a short distance.
 Practice turning, stopping and
reversing with the trailer attached in
an area away from traffic until you
become accustomed to the feel of
the vehicle-trailer combination.
 Reversing with a tr ailer attached is
difficult and requires practice. Grip
the bottom of the steering wheel
and move your hand to the left to
move the trailer to the left. Move
your hand to the right to move the
trailer to right. (This is generally
opposite to reversing without a
trailer attached.) Avoid sharp or
prolonged turning. Have someone
guide you when reversing to reduce
the risk of an accident.
 As stopping distance is increased
when towing a trailer, vehicle-to
vehicle distance should be
increased. For each 10 mph (16
km/h) of speed, allow at least one
vehicle and trailer length.
 Avoid sudden braking as you may skid, resulting in the trailer jackknif-
ing and a loss of vehicle control. This
is especially true on wet or slippery
surfaces.
 Avoid jerky starts or sudden accel-
eration.
 Avoid jerky steering and sharp
turns, and slow down before making
turn.
 Note that when making a turn, the
trailer wheels will be closer than the
vehicle wheels to the inside of the
turn. Compensate by making a
wider than normal turning radius.
 Slow down before making a turn, in
cross winds, on wet or slippery sur-
faces, etc. Increasing vehicle speed
can destabilize the trailer.
 Take care when passing other vehi-
cles. Passing requires considerable
distance. After pass ing a vehicle, do
not forget the length of your trailer,
and be sure you have plenty of room
before changing lanes.
 To maintain engine braking effi-
ciency and charging system perfor-
mance when using engine braking,
do not put the transmission in D.
( P.191)
 Instability happens more frequently
when descending steep or long
downhill grades. Before descend-
ing, slow down and downshift. Do
not make sudden downshifts while
descending steep or long downhill
grades.
 Avoid holding the brake pedal down
too long or applying the brakes too

1824-1. Before driving
frequently. This could cause the
brakes to overheat and result in
reduced braking efficiency.
 Due to the added load of the trailer,
your vehicle’s engine may overheat
on hot days (at temperatures over
85°F [30°C]) when driving up a
long or steep grade. If the engine
coolant temperature gauge indi-
cates overheating, immediately turn
off the air conditioning (if in use),
pull your vehicle off the road and
stop in a safe spot. ( P.454)
 Always place wheel blocks under
both the vehicle’s and the trailer’s
wheels when parking. Put the trans-
mission in P and apply the parking
brake. Avoid parking on a slope, but
if unavoidable, do so only after per-
forming the following:
1 Apply the brakes and keep them
applied.
2 Have someone place wheel blocks
under both the vehicle’s and trailer’s
wheels.
3 When the wheel blocks are in
place, release the brakes slowly
until the blocks absorb the load.
4 Shift into P and apply the parking
brake.
5 Turn off the hybrid system.
 When restarting after parking on a
slope:
1 With the transmission in P, start the
hybrid system. Be sure to keep the
brake pedal depressed. 2
Shift into a forward gear. If revers-
ing, shift into R.
3 If the parking brake is in manual
mode, release the parking brake.
(P.195)
4 Release the brake pedal, and slowly
pull or back away from the wheel
blocks. Stop and apply the brakes.
5 Have someone retrieve the blocks.

1994-2. Driving procedures
4
Driving
play. The parking brake will then be set
automatically.
■Brake hold function
●If the brake pedal is left released for a
period of about 3 minutes after the sys-
tem has started holding the brake, the
parking brake will be set automatically. In
this case, a warning buzzer sounds and a
message is shown on the multi-informa-
tion display.
●To turn the system off while the system is
holding the brake, firmly depress the
brake pedal and press the button again.
●The brake hold function may not hold the
vehicle when the vehicle is on a steep
incline. In this situation, it may be neces-
sary for the driver to apply the brakes. A
warning buzzer will sound and the
multi-information display will inform the
driver of this situation. If a warning mes-
sage is shown on the multi-information
display, read the message and follow the
instructions.
■When the parking brake is set automati-
cally while the system is holding the
brakes
Perform any of the follo wing operations to
release the parking brake.
●Depress the accelerator pedal. (The
parking brake will not be released auto-
matically if the seat belt is not fastened.)
●Operate the parking brake switch with
the brake pedal depressed.
Make sure that the pa rking brake indicator
light goes off. ( P.195)
■When an inspection at your Lexus
dealer is necessary
When the brake hold standby indicator
(green) does not illuminate even when the
brake hold switch is pressed with the brake
hold system operating conditions met, the
system may be malfun ctioning. Have the
vehicle inspected at your Lexus dealer.
■If “Brake Hold Fault Depress Brake to
Deactivate Visit Your Dealer” or “Brake
Hold Malfunction Visit Your Dealer” is
displayed on the multi-information dis-
play
The system may be ma lfunctioning. Have
the vehicle inspected by your Lexus dealer.
■Warning messages and buzzers
Warning messages and buzzers are used to
indicate a system malfunction or to inform
the driver of the need for caution. If a warn-
ing message is shown on the multi-informa-
tion display, read the message and follow
the instructions.
■If the brake hold operated indicator
flashes
 P.425
WARNING
■When the vehicle is on a steep incline
When using the brake hold system on a
steep incline exercise caution. The brake
hold function may not hold the vehicle in
such a situation.
■When stopped on a slippery road
The system cannot stop the vehicle when
the gripping ability of the tires has been
exceeded. Do not use the system when
stopped on a slippery road.
NOTICE
■When parking the vehicle
The brake hold system is not designed
for use when parking the vehicle for a
long period of time. Turning the power
switch off while the system is holding the
brake may release the brake, which
would cause the vehicle to move. When
operating the power switch, depress the
brake pedal, shift the shift lever to P and
set the parking brake.

2204-5. Using the driving support systems
The system can detect the following:
Vehicles
 Bicyclists
 Pedestrians
■Pre-collision warning
When the system determines that the
possibility of a frontal collision is high, a
buzzer will sound and a warning mes-
sage will be displayed on the
multi-information display to urge the driver to take evasive action.
■Pre-collision brake assist
When the system determines that the
possibility of a frontal collision is high,
the system applies greater braking
force in relation to how strongly the
brake pedal is depressed.
■Pre-collision braking
If the system determines that the possi-
bility of a frontal collision is extremely
high, the brakes are automatically
applied to help avoid the collision or
reduce the impact of the collision.
■Suspension control (if equipped)
When the system determines that the
possibility of a frontal collision is high,
the Adaptive Variable Suspension Sys-
tem ( P.284) will control the damp-
ing force of the shock absorbers to
help maintain an appropriate vehicle
posture.
PCS (Pre-Collision System)
The pre-collision system uses a
radar sensor and front camera to
detect objects ( P.220) in front of
the vehicle. When the system
determines that the possibility of a
frontal collision with an object is
high, a warning operates to urge
the driver to take evasive action
and the potential brake pressure is
increased to help the driver avoid
the collision. If the system deter-
mines that the possibility of a frontal
collision with an object is extremely
high, the brakes are automatically
applied to help avoid the collision or
help reduce the impact of the colli-
sion.
The pre-collision system can be dis-
abled/enabled and the warning tim-
ing can be changed. ( P.222)
Detectable objects
System functions

2264-5. Using the driving support systems
• If a vehicle ahead is a child sized bicycle, a bicycle that is carrying a large load, a
bicycle ridden by more than one person,
or a uniquely shaped bicycle (bicycle with
a child seat, tandem bicycle, etc.)
• If a pedestrian/or the riding height of a
bicyclist ahead is shorter than approxi-
mately 3.2 ft. (1 m) or taller than approxi-
mately 6.5 ft. (2 m)
• If a pedestrian/bicyclist is wearing over- sized clothing (a rain coat, long skirt,
etc.), making their silhouette obscure
• If a pedestrian is bending forward or squatting or bicyclist is bending forward
• If a pedestrian/bicyclist is moving fast
• If a pedestrian is pushing a stroller, wheel-
chair, bicycle or other vehicle
• When driving in incl ement weather such
as heavy rain, fog, snow or a sandstorm
• When driving through steam or smoke
• When the surrounding area is dim, such as at dawn or dusk, or while at night or in
a tunnel, making a detectable object
appear to be nearly the same color as its
surroundings
• When driving in a place where the sur- rounding brightness changes suddenly,
such as at the entrance or exit of a tunnel
• After the hybrid system has started the vehicle has not been driven for a certain
amount of time
• While making a left/right turn and for a few seconds after makin g a left/right turn
• While driving on a curve and for a few seconds after driving on a curve
• If your vehicle is skidding
• If the front of the vehicle is raised or low-
ered
• If the wheels are misaligned
• If a wiper blade is blocking the front cam- era
• The vehicle is being driven at extremely
high speeds
• When driving on a hill • If the radar sensor or front camera is mis-
aligned
●In some situations su ch as the following,
sufficient braking force may not be
obtained, preventing the system from
performing properly:
• If the braking functions cannot operate to their full extent, such as when the brake
parts are extremely cold, extremely hot,
or wet
• If the vehicle is not properly maintained
(brakes or tires are excessively worn,
improper tire inflation pressure, etc.)
• When the vehicle is being driven on a
gravel road or other slippery surface
■If VSC is disabled
●If VSC is disabled ( P.285), the
pre-collision brake assist and pre-colli-
sion braking functions are also disabled.
●The PCS warning light will turn on and
“VSC Turned Off Pre-Collision Brake
System Unavailable” will be displayed on
the multi-information display.

2414-5. Using the driving support systems
4
Driving
328 ft. (100 m) ahead, determines the current vehicle-to-vehicle following dis-
tance, and operates to maintain a suitab le following distance from the vehicle
ahead. The desired vehicle-to-vehicle distance can also be set by operating the
vehicle-to-vehicle distance switch.
When driving on downhill slopes, the vehicl e-to-vehicle distance may become shorter.
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver.
Example of deceleration cruising and follow-up cruising
When a preceding vehicle driving slower than the set speed appears
When a vehicle is detected running ahead of you, the system automatically decelerates
your vehicle. When a greater reduction in vehicle speed is necessary, the system applies
the brakes (the stop lights will come on at this time). The system will respond to changes in
the speed of the vehicle ahead in order to maintain the vehicle-to-vehicle distance set by
the driver. Approach warning warns you when th e system cannot decelerate sufficiently to
prevent your vehicle from closing in on the vehicle ahead.
When the vehicle ahead of you stops, your vehi cle will also stop (vehicle is stopped by sys-
tem control). After the vehicle ahead starts off, pushing the cruise control lever up or
depressing the accelerator pedal (start-off operation) will resume follow-up cruising. If the
start-off operation is not performed, system control continues to keep your vehicle
stopped.
When the turn signal lever is operated and yo ur vehicle moves to an overtaking lane while
driving at 50 mph (80 km/h) or more, the vehicle will accelerate to help to overtake a
passing vehicle.
The system’s identification of what is an over taking lane may be determined solely based on
the location of the steering wheel in the vehicl e (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
A
B

2584-5. Using the driving support systems
sible.
• There will be a short delay between object detection and display. Even at low
speeds, there is a possibility that the
object will come within the sensor’s
detection areas before the display is
shown and the warning beep sounds.
• It might be difficult to hear the buzzer due to the volume of the audio system or air
flow noise of the air conditioning system.
• It may be difficult to hear the buzzer if buzzers for other systems are sounding.
■Conditions under which the function
may not function correctly
Certain vehicle conditions and the sur-
rounding environment may affect the ability
of a sensor to correctly detect objects. Par-
ticular instances where this may occur are
listed below.
●There is dirt, snow or ice on a sensor.
(Cleaning the sensors will resolve this
problem.)
●A sensor is frozen. (Thawing the area will
resolve this problem.)
In especially cold weather, if a sensor is
frozen the sensor display may be dis-
played abnormally, or objects, such as a
wall, may not be detected.
●A sensor is covered in any way.
●When a sensor or the area around a sen-
sor is extremely hot or cold.
●On an extremely bumpy road, on an
incline, on gravel, or on grass.
●The vicinity of the vehicle is noisy due to
vehicle horns, motorcycle engines, air
brakes of large vehicles, or other loud
noises producing ultrasonic waves.
●There is another vehicle equipped with
parking assist sensors in the vicinity.
●A sensor is coated with a sheet of spray
or heavy rain.
●If a sensor is hit by a large amount of
water, such as when driving on a flooded
road.
●If the vehicle is significantly tilted.
●The vehicle is approaching a tall or
curved curb.
●If objects draw too close to the sensor.
■Objects which may not be properly
detected
The shape of the object may prevent the
sensor from detectin g it. Pay particular
attention to the following objects:
●Wires, fences, ropes, etc.
●Cotton, snow and other materials that
absorb sound waves
●Sharply-angled objects
●Low objects
●Tall objects with upper sections project-
ing outwards in the direction of your vehi-
cle
People may not be de tected if they are
wearing certain types of clothing.
■Detection range of the sensors
Approximately 3.3 ft. (100 cm)
Approximately 4.9 ft. (150 cm)
Approximately 2.0 ft. (60 cm)
The diagram shows the detection range of
the sensors. Note that the sensors cannot
detect objects that are extremely close to
the vehicle.
The range of the sensors may change
depending on the shape of the object, etc.
Sensor detection display, object
distance
A
B
C

2654-5. Using the driving support systems
4
Driving
turned on
• Immediately after the hybrid system is started with the RCTA function on
• When the sensors cannot detect a vehi- cle due to obstructions
●Instances of the RCTA function unneces-
sarily detecting a vehicle and/or object
may increase in the following situations:
• When a vehicle passes by the side of your vehicle
• When the parking space faces a street
and vehicles are being driven on the
street
• When the distance between your vehicle and metal objects, such as a guardrail,
wall, sign, or parked vehicle, which may
reflect electrical waves toward the rear of
the vehicle, is short
• When a towing eyelet is installed to the
rear of the vehicle
*: If equipped
■Parking Support Brake function
(static objects) (if equipped)
Ultrasonic sensors are used to detect
static objects, such as a wall, in the
detection area when driving at a low
speed or backing up. ( P.271)
■Parking Support Brake function
(rear-crossing vehicles) (if
equipped)
Rear radar sensors are used to detect
approaching vehicles in the detection
area behind the vehicle when backing
up. ( P.277)
PKSB (Parking Support
Brake)*
The Parking Support Brake 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 is high, a
warning operates to urge the driver
to take evasive action. If the system
determines that the possibility of a
collision with a detected object is
extremely high, the brakes are
automatically applied to help avoid
the collision or help reduce the
impact of the collision.
PKSB (Parking Support Brake)
system

2674-5. Using the driving support systems
4
Driving
Multi-information display: “Object
Detected Acceleration Reduced”
PKSB OFF indicator: Not illuminated
Buzzer: Does not sound
Hybrid system output restriction
control is operating (output
restricted as much as possible)
The system has dete rmined that stron-
ger-than-normal brake operation is neces-
sary.
Center Display (Panoramic view monitor)
(If equipped): “BRAKE!”
Multi-information display: “BRAKE!”
PKSB OFF indicator: Not illuminated
Buzzer: Short beep
 Brake control is operating
The system determined that emergency
braking is necessary. Center Display (Panoramic view monitor)
(If equipped): “BRAKE!”
Multi-information display: “BRAKE!”
PKSB OFF indicator: Not illuminated
Buzzer: Short beep

Vehicle stopped by system opera-
tion
The vehicle has been stopped by brake
control operation.
Center Display (Panoramic view monitor)
(If equipped): “Press Brake Pedal”
Multi-information display: “Switch to
Brake” (If the accelerator pedal is not
depressed, “Press Brake Pedal” will be dis-
played.)
PKSB OFF indicator: Illuminated
Buzzer: Short beep
If the Parking Support Brake determines that a collision with a detected object is
possible, the hybrid system output will be re stricted to restrain any increase in the
vehicle speed. (Hybrid system output restriction control: See figure 2.)
Additionally, if the accelerator pedal contin ues to be depressed, the brakes will be
applied automatically to redu ce the vehicle speed. (Brake control: See figure 3.)
 Figure 1 When the PKSB (Parki ng Support Brake) is disabled
System overview

2754-5. Using the driving support systems
4
Driving
• When parallel parking
• When there is a rut or hole in the surface of the road
• When driving on a metal cover (grating), such as those used for drainage ditches
• When driving on a steep slope
• If a sensor is hit by a large amount of
water, such as when driving on a flooded
road
●Weather
• If a sensor is covered with ice, snow, dirt,
etc. (when cleared, the system will return
to normal)
• If heavy rain or water strikes a sensor
• When driving in incl ement weather such
as fog, snow or a sandstorm
• When strong winds are blowing
●Other ultrasonic wave sources
• When vehicle horns, vehicle detectors,
motorcycle engines, air brakes of large
vehicles, the clearance sonar of other
vehicles or other devices which produce
ultrasonic waves are near the vehicle
• If a sticker or an el ectronic component,
such as a backlit license plate (especially
fluorescent type), fog lights, fender pole
or wireless antenna is installed near a
sensor
●Changes in the vehicle posture
• If the vehicle is significantly tilted
• If the front of the vehicle is raised or low-
ered due to the carried load
• If the orientation of a sensor has been
changed due to a collision or other
impact
■Situations in which the Parking Support
Brake function (stati c objects) may not
operate properly
In some situations, such as the following, this
function may not operate properly.
●Weather
• When a sensor or the area around a sen- sor is extremely hot or cold • When strong winds are blowing
• If a sensor is covered with ice, snow, dirt,
etc. (when cleared, the system will return
to normal)
• If heavy rain or water strikes a sensor
• When driving in incl ement weather such
as fog, snow or a sandstorm
• When the sensor is frozen (Once the
sensor thaws, the system will return to
normal)
●Vehicle surroundings
• When an object that cannot be detected is between the vehicle and a detected
object
• If an object such as a vehicle, motorcycle, bicycle or pedestrian cuts in front of the
vehicle or runs out from the side of the
vehicle
• The vehicle is approaching a tall or
curved curb.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• If objects draw too close to the sensor.
●Other ultrasonic waves sources
• When vehicle horns, vehicle detectors, motorcycle engines, air brakes of large
vehicles, the clearance sonar of other
vehicles or other de vices which produce
ultrasonic waves are near the vehicle
• If a sticker or an electronic component, such as a backlit license plate (especially
fluorescent type), fog lights, fender pole
or wireless antenna is installed near a
sensor