brake LEXUS RX450h 2021 Repair Manual

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

2684-5. Using the driving support systems
Hybrid system output
Braking force
Time
 Figure 2 When hybrid system ou tput restriction control operates
Hybrid system output
Braking force
Time
Hybrid system output restrict ion control begins operating
System determines that po ssibility of collision with detected object is high
Hybrid system output reduced
Example: Multi-informat ion display: “BRAKE!”A
B
C
A
B
C
D
E
F
G

2694-5. Using the driving support systems
4
Driving
Figure 3 When brake control operates
Hybrid system output
Braking force
Time
Hybrid system output restrict ion control begins operating
System determines that po ssibility of collision with detected object is high
Hybrid system output reduced
System determines that possibility of col lision with detected object is extremely
high
Brake control begins operating
Brake control strength increased
Example: Multi-informat ion display: “BRAKE!”
Example: Multi-information display: “Switch to Brake”
■If the Parking Support Brake has oper-
ated
If the vehicle is stopped due to operation of
the Parking Support Brake, the Parking
Support Brake will be disabled and the
PKSB OFF indicator will illuminate. If the
Parking Support Brake operates unneces-
sarily, brake control can be canceled by
depressing the brake pedal or waiting for
approximately 2 seconds for it to automati-
cally be canceled. Then, the vehicle can be
operated by depressing the accelerator
pedal.■Re-enabling the Parking Support Brake
To re-enable the Parking Support Brake
when it has been disabled due to system
operation perform any of the following
operations.
At this time, the PKSB OFF indicator will
turn off. ( P.80)
●Turn the PKSB (Parking Support Brake)
on ( P.266)
●The shift lever is in P.
●Drive with no operation targets in the
traveling direction of the vehicle
A
B
C
D
E
F
G
H
I
J
K

2704-5. Using the driving support systems
●Change the traveling direction of the
vehicle
■If “Parking Support Brake Unavailable”
is displayed on the multi-information
display and the PKSB OFF indicator is
flashing
●If this message is displayed only when the
shift lever is in any position other than R, a
sensor on the front or rear bumper may
be dirty. Clean the sensors and their sur-
rounding area on the bumpers.
●Initialization may no t have been per-
formed after a 12-volt battery terminal
was disconnected and reconnected. Ini-
tialize the system. ( P.270)
If this message continues to be displayed
even after init ialization, have the vehicle
inspected by your Lexus dealer.
■If “Parking Assist Unavailable” and
“Parking Assist Unavailable Clean
Parking Assist Sensor” are displayed on
the multi-informatio n display and the
PKSB OFF indicator is flashing
●A sensor may be covered with ice, snow,
dirt, etc. Remove the ice, snow, dirt, etc.,
from the sensor to return the system to
normal.
If this message is shown even after
removing dirt from the sensor, or shown
when the sensor was not dirty to begin
with, have the vehicle inspected by your
Lexus dealer.
●A sensor may be frozen. Once the ice
melts, the system will return to normal.
●Water may be continuo usly flowing over
the sensor surface, such as in a heavy
rain. When the system determines that it
is normal, the system will return to nor-
mal.
■If a 12-volt battery terminal has been
disconnected and reconnected
The system needs to be initialized. To initial-
ize the system, drive the vehicle straight
ahead for 5 seconds or more at a speed of
approximately 22 mph (35 km/h) or more.
Additionally, for vehicles with the Parking
Support Brake function, turn the steering
wheel fully to the left and right with the vehi-
cle stopped.

2714-5. Using the driving support systems
4
Driving
*:If equipped
This function will operate in situations such as the following if an object is detected
in the traveling direction of the vehicle.
■When traveling at a low speed and the brake pedal is not depressed, or is
depressed late
Parking Support Brake function (static objects)*
If the sensors detect a static object, such as a wall, in the travelling direction of
the vehicle and the system determines that a collision may occur due to the
vehicle suddenly moving forward due to an accidental accelerator pedal oper-
ation, the vehicle moving the unintended direction due to the wrong shift lever
position, or while parking or traveling at low speeds, the system will operate to
lessen the impact with th e detected static object and reduce the resulting
damage.
Examples of function operation

2724-5. Using the driving support systems
■When the accelerator pedal is depressed excessively
■When the vehicle moves in the unintend ed direction due to the wrong shift
lever position
 P.255
Types of sensors
WARNING
■To ensure the Parking Support Brake
can operate properly
Observe the following precautions
regarding the sensors (
P.255). Failure
to do so may cause a sensor to not oper-
ate properly, and may cause an accident.
●Do not modify, disassemble or paint
the sensors.
●Do not replace a sensor with a part
other than a genuine part.
●Do not subject a sensor or its sur-
rounding area to a strong impact.
●Do not damage the sensors, and
always keep them clean.

2734-5. Using the driving support systems
4
Driving
■The Parking Support Brake function
(static object) will operate when
The function will operate when the PKSB
OFF indicator is not illuminated or flashing
(  P.79, 80) and all of the following condi-
tions are met:
●Hybrid system output restriction control
• The Parking Support Brake is enabled.
• The vehicle speed is 9 mph (15 km/h) or less.
• There is a static object in the traveling direction of the vehicle and 6 to 13 ft. (2
to 4 m) away.
• The Parking Support Brake determines that a stronger-than-normal brake opera-
tion is necessary to avoid a collision.
●Brake control
• Hybrid system output restriction control
is operating.
• The Parking Support Brake determines that an immediate brake operation is nec-
essary to avoid a collision.
■The Parking Support Brake function
(static objects) will stop operating when
The function will stop operating if any of the
following conditions are met:
●Hybrid system output restriction control
• The Parking Support Brake is disabled.
• The system determines that the collision has become avoidable with normal brake
operation.
• The static object is no longer 6 to 13 ft. (2
to 4 m) away from the vehicle or in the
WARNING
■Handling the suspension
Do not modify the suspension, as
changes to the height or inclination of the
vehicle may prevent the sensors from
detecting objects correctly or cause the
system to not operate or operate unnec-
essarily.
■If the Parking Support Brake function
(static objects) operates unnecessar-
ily, such as at a railroad crossing
In the event that the Parking Support
Brake function (static objects) operates
unnecessarily, such as at a railroad cross-
ing, brake control w ill be canceled after
approximately 2 seconds, allowing you
to proceed forward and leave the area,
brake control can also be canceled by
depressing the brake pedal. Depressing
the accelerator pedal after brake control
is canceled will allow you to proceed for-
ward and leave the area.
■Notes when washing the vehicle
Do not apply intensive bursts of water or
steam to the sensor area.
Doing so may result in the sensor mal-
functioning.
●When using a high pressure washer to
wash the vehicle, do not spray the sen-
sors directly, as doing so may cause a
sensor to malfunction.
●When using steam to clean the vehicle,
do not direct steam too close to the
sensors as doing so may cause a sen-
sor to malfunction.
■When to disable the Parking Support
Brake
In the following situations, disable the
Parking Support Brake as the system
may operate even though there is no
possibility of a collision.
●When inspecting the vehicle using a
chassis roller, chassis dynamo or free
roller
●When loading the vehicle onto a boat,
truck or other transport vessel
●If the suspension has been modified or
tires of a size othe r than specified are
installed
●If the front of the vehicle is raised or
lowered due to the carried load
●When equipment that may obstruct a
sensor is installed, such as a towing
eyelet, bumper protector (an addi-
tional trim strip, etc.), bicycle carrier, or
snow plow
●When using an automatic car wash

2744-5. Using the driving support systems
traveling direction of the vehicle.
●Brake control
• The Parking Support Brake is disabled.
• Approximately 2 seconds have elapsed since the vehicle was stopped by brake
control.
• The brake pedal is depressed after the vehicle is stopped by brake control.
• The static object is no longer 6 to 13 ft. (2 to 4 m) away from the vehicle or in the
traveling direction of the vehicle.
■Re-enabling the Parking Support Brake
function (static objects)
 P.270
■Detection range of the Parking Support
Brake function (static objects)
The detection range of the Parking Support
Brake function (static objects) differs from
the detection range of the intuitive parking
assist. ( P.258) Therefore, even if the intu-
itive parking assist detects an object and
provides a warning, the Parking Support
Brake function (static objects) may not start
operating.
■Objects that the Parking Support Brake
function (static obje cts) may not detect
The sensors may not be able to detect cer-
tain objects, such as the following:
●Pedestrian
●Cotton cloth, snow, and other materials
that are poor reflectors of ultrasonic
waves
●Objects which are not perpendicular to
the ground, are not perpendicular to the
traveling direction of the vehicle, are
uneven or are waving
●Low objects
●Thin objects such as wires, fences, ropes
and signposts
●Objects that are extremely close to the
bumper
●Sharply-angled objects
●Tall objects with upper sections project-
ing outwards in the direction of your vehi-
cle
■Situation in which the Parking Support
Brake function (static objects) may not
operate
When driving with the shift lever in N.
■Intuitive parking assist buzzer
Regardless of whether the intuitive parking
assist system is enabled or not ( P.256), if
the Parking Support Brake function (static
objects) is enabled ( P.266), the front or
rear sensors detect an object and brake
control is performed, the intuitive parking
assist buzzer will sound to notify the driver
of the approximate distance to the object.
■Situations in which the Parking Support
Brake function (static objects) may
operate even if there is no possibility of a
collision
In some situations, such as the following, the
Parking Support Brake function (static
objects) may operate even though there is
no possibility of a collision.
●Vehicle surroundings
• When driving on a narrow road
• When driving on a gravel road or in an area with tall grass
• When driving toward a banner, flag, low-hanging branch or boom barrier
(such as those used at railroad crossings,
toll gates and parking lots)
• When driving on a narrow path sur-
rounded by a structure, such as in a tun-
nel or on an iron bridge

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

2774-5. Using the driving support systems
4
Driving
*:If equipped
This function will operate in situations such as the following if a vehicle is detected
in the traveling direction of the vehicle.
■When reversing, a vehicle is appr oaching and the brake pedal is not
depressed, or is depressed late
 P.249
Parking Support Brake function (rear-crossing vehicles)*
If a rear radar sensor detects a vehicle a pproaching from the right or left at the
rear of the vehicle and the system determ ines that the possibility of a collision
is high, this function will perform brak e control to reduce the likelihood of an
impact with the approaching vehicle.
Examples of function operation
Types of sensors
WARNING
■To ensure the Parking Support Brake
function (rear-crossing vehicles) can
operate properly
Observe the following precautions
regarding the rear side radar sensors
(
P.249). Failure to do so may cause a
sensor to not operate properly, and may
cause an accident.
●Do not modify, disassemble or paint
the sensors.
●Do not replace a rear side radar sen-
sor with a part other than a genuine
part.
●Do not damage the rear side radar
sensors, and always keep the radar
sensors and their surrounding area on
the bumper clean.