brake LEXUS IS300 2021 Owner's Guide

1724-5. Using the driving support systems
WARNING
• Conditions under which the system may not operate properly:
P.177
●Do not attempt to test the operation of
the pre-collision system yourself.
Depending on the objects used for
testing (dummies, cardboard objects
imitating detectable objects, etc.), the
system may not operate properly, pos-
sibly leading to an accident.
■Pre-collision braking
●When the pre-collision braking func-
tion is operating, a large amount of
braking force will be applied.
●If the vehicle is stopped by the opera-
tion of the pre-collision braking func-
tion, the pre-collision braking function
operation will be canceled after
approximately 2 seco nds. Depress the
brake pedal as necessary.
●The pre-collision braking function may
not operate if certain operations are
performed by the driver. If the acceler-
ator pedal is being depressed strongly
or the steering wheel is being turned,
the system may determine that the
driver is taking evasive action and pos-
sibly prevent the pre-collision braking
function from operating.
●In some situations, while the pre-colli-
sion braking function is operating,
operation of the function may be can-
celed if the accelerator pedal is
depressed strongly or the steering
wheel is turned and the system deter-
mines that the driver is taking evasive
action.
●If the brake pedal is being depressed,
the system may determine that the
driver is taking evasive action and pos-
sibly delay the operation timing of the
pre-collision braking function.
■Emergency steering assist
●As emergency steering assist opera-
tion will be canceled when the system
determines that lane departure pre-
vention function ha s been completed.
●Emergency steering assist may not
operate or may be canceled in the fol-
lowing cases as the system may deter-
mine the driver is taking actions.
• If the accelerator pedal is being depressed strongly, the steering wheel
is being operated sharply, the brake
pedal is being depressed or the turn
signal lever is being operated. In this
case, the system may determine that
the driver is taking evasive action and
the emergency steering assist may not
operate.
• In some situations, while the emer- gency steering assist is operating,
operation of the function may be can-
celed if the accelerator pedal is
depressed strongly, the steering wheel
is operated sharply or the brake pedal
is being depressed and the system
determines that the driver is taking
evasive action.
• When the emergency steering assist is operating, if the stee ring wheel is held
firmly or is operated in the opposite
direction to that which the system is
generating torque, the function may be
canceled.
■When to disable the pre-collision sys-
tem
In the following situations, disable the
system, as it may not operate properly,
possibly leading to an accident resulting
in death or serious injury:
●When the vehicle is being towed
●When your vehicle is towing another
vehicle
●When transporting the vehicle via
truck, boat, train or similar means of
transportation

1744-5. Using the driving support systems
1Early
2 Middle
This is the default setting.
3Late
■Operational conditions for each
pre-collision function
The pre-collision system is enabled and the
system determines that the possibility of a
frontal collision with a detected object is
high.
The system may not operate in the following
situations:
• If a battery terminal has been discon- nected and reconnected and then the
vehicle has not been driven for a certain
amount of time
• If the shift lever is in R
• When the VSC OFF indicator is illumi- nated (only the pre-collision warning
function will be operational)
The operation speeds and operation cancellation for each function is listed below.
●Pre-collision warning
While the pre-collision warning function is operat ing, if the steering wheel is operated heav-
ily or suddenly, the pre-collis ion warning may be cancelled.
●Pre-collision brake assist
●Pre-collision braking
Detectable objectsVehicle speedRelative speed between your
vehicle and object
Preceding and stopped vehi- clesApprox. 7 to 110 mph (10 to 180 km/h)Approx. 7 to 110 mph (10 to 180 km/h)
Oncoming vehiclesApprox. 7 to 110 mph (10 to 180 km/h)Approx. 13 to 110 mph (20 to 180 km/h)
Bicyclists and pedestriansApprox. 7 to 50 mph (10 to 80 km/h)Approx. 7 to 50 mph (10 to 80 km/h)
Detectable objectsVehicle speedRelative speed between your vehicle and object
Preceding and stopped vehi- clesApprox. 20 to 110 mph (30 to 180 km/h)Approx. 20 to 110 mph (30 to 180 km/h)
Bicyclists and pedestriansApprox. 20 to 50 mph (30 to 80 km/h)Approx. 20 to 50 mph (30 to 80 km/h)

1754-5. Using the driving support systems
4
Driving
If either of the following occur while the pre-collision braking function is operating, it will be
canceled:
• The accelerator pedal is depressed strongly.
• The steering wheel is turned sharply or abruptly.
●Emergency steering assist
When the turn signal lights are flashing, emergency steering assist will not operate in case of
an emergency.
If any of the following occur while the emergency st eering assist function is operating, it will
be canceled:
• The accelerator pedal is depressed strongly.
• The steering wheel is turned sharply or abruptly.
• The brake pedal is depressed.
●Intersection right/left turn a ssistance (pre-collision warning)
When the turn signal lights are not flashing, suppor t for turning left or right at an intersection
which targets oncoming vehicles does not work.
●Intersection right/left turn a ssistance (pre-collision braking)
Detectable objectsVehicle speedRelative speed between your
vehicle and object
Preceding and stopped vehi- clesApprox. 7 to 110 mph (10 to 180 km/h)Approx. 7 to 110 mph (10 to 180 km/h)
Oncoming vehiclesApprox. 7 to 110 mph (10 to 180 km/h)Approx. 13 to 110 mph (20 to 180 km/h)
Bicyclists and pedestriansApprox. 7 to 50 mph (10 to 80 km/h)Approx. 7 to 50 mph (10 to 80 km/h)
Detectable objectsVehicle speedRelative speed between your vehicle and object
Preceding and stopped vehi-cles, bicyclists and pedestri- ansApprox. 25 to 50 mph (40 to 80 km/h)Approx. 25 to 50 mph (40 to 80 km/h)
Detectable objectsVehicle speedOncoming vehicle speedRelative speed
between your vehi- cle and object
Oncoming vehiclesApprox. 7 to 15 mph (10 to 25 km/h)Approx. 20 to 35
mph (30 to 55 km/h)Approx. 25 to 50 mph (40 to 80 km/h)
PedestriansApprox. 7 to 15 mph (10 to 25 km/h)Approx. 7 to 15 mph (10 to 25 km/h)

1794-5. Using the driving support systems
4
Driving
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 engine 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
• When driving in a tr affic lane separated
by more than one lane where oncoming
vehicles are driving while making a
right/left turn
• When largely out of place with the oppo- site facing targeted oncoming vehicle
during a right/left turn • While making a right/left turn, when a
pedestrian approaches from behind or
side of your vehicle
●In addition to the above, in some situa-
tions, such as the following, the emer-
gency steering assist may not operate.
• When the white (yellow) lane lines are difficult to see, such as when they are
faint, diverging/merging, or a shadow is
cast upon them
•When the lane is wi der or narrower than
normal
• When there is a light and dark pattern on the road surface, such as due to road
repairs
• When the target is too close
• When there is insuffic ient safe or unob-
structed space for the vehicle to be
steered into
• If oncoming vehicle is present
• If VSC function is operating
●In some situations su ch as the following,
sufficient braking forc e or steering force
may not be obtained, preventing the sys-
tem 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
• When the road surface has deep wheel tracks
• When driving on a hill road
• When driving on a road that has inclines
to the left or right
■If VSC is disabled
●If VSC is disabled ( P.239), the
pre-collision brake assist and pre-colli-
sion braking functions are also disabled.

1804-5. Using the driving support systems
●The PCS warning light will turn on and
“VSC Turned OFF Pre-Collision Brake
System Unavailable” will be displayed on
the multi-information display.LTA (Lane Tracing Assist)
While driving on a road with clear
white (yellow) lane lines, the LTA
system warns the driver if the vehi-
cle may deviate from the current
lane or course
*, and also can
slightly operate the steering wheel
to help avoid deviation from the
lane or course
*. Also, while the
dynamic radar cruise control with
full-speed range ( P.192) is oper-
ating, this system will operate the
steering wheel to maintain the vehi-
cle’s lane position.
The LTA system recognizes white
(yellow) lane lines or a course
*
using the front camera. Addition-
ally, it detects preceding vehicles
using the front camera and radar.
*: Boundary between asphalt and the side of the road, such as grass, soil, or
a curb

1944-5. Using the driving support systems
This mode employs a radar to detect the presence of vehicles up to approximately
328 ft. (100 m) ahead, determines the cu rrent 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
Driving in vehicle-to-vehicle distance control mode
A
B

1974-5. Using the driving support systems
4
Driving
Select a distance from the table below.
Note that the distances shown corre-
spond to a vehicle speed of 50 mph
(80 km/h). Vehicle-to-vehicle distance
increases/decreases in accordance
with vehicle speed. When the vehicle is
stopped by system control, the vehicle
stops at a certain vehicle-to-vehicle
distance depending on the situation.
After the vehicle ahead of you starts
off, push the lever up.
Your vehicle will also resume follow-up
cruising if the accelerator pedal is
depressed after the vehicle ahead of
you starts off.1
Pulling the lever toward you can-
cels the speed control.
The speed control is also canceled when
the brake pedal is depressed. (When the
vehicle has been stopped by system con-
trol, depressing the brake pedal does not
cancel the setting.)
2Pushing the lever up resumes the
cruise control and returns vehicle
speed to the set speed.
When your vehicle is too close to a
vehicle ahead, and sufficient automatic
deceleration via the cruise control is
not possible, the display will flash and
the buzzer will sound to alert the driver.
Vehicle-to-vehicle distance set-
tings (vehicle-to-vehicle dis-
tance control mode)
Distance optionsVehicle-to-vehicle dis- tance
LongApproximately 160 ft. (50 m)
MediumApproximately 130 ft. (40 m)
ShortApproximately 100 ft. (30 m)
Resuming follow-up cruising
when the vehicle has been
stopped by system control (vehi-
cle-to-vehicle distance control
mode)
Canceling and resuming the
speed control
Approach warning (vehi-
cle-to-vehicle distance control
mode)

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

2004-5. Using the driving support systems
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is
turned off.
●The sensor cannot detect correctly
because it is covered in some way.
●When the brake control or output restric-
tion control of a driving support system
operates.
(For example: Pre-Collision System,
Drive-Start Control)
●The parking brake is operated.
●The vehicle is stopped by system control
on a steep incline.
●The following are detected when the
vehicle has been stopped by system con-
trol:
• The driver is not wearing a seat belt.
• The driver’s door is opened.
• The vehicle has been stopped for about 3 minutes.
If vehicle-to-vehicle distance control mode
is automatically canceled for any reasons
other than the above, there may be a mal-
function in the system . Contact your Lexus
dealer.
■Automatic cancelation of constant
speed control mode
Constant speed control mode is automati-
cally canceled in the following situations:
●Actual vehicle speed is more than
approximately 10 mph (16 km/h) below
the set vehicle speed.
●Actual vehicle speed falls below approxi-
mately 20 mph (30 km/h).
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is
turned off.
●When the brake control or output restric-
tion control of a driving support system
operates.
(For example: Pre-Collision System,
Drive-Start Control)
●The parking brake is operated.
If constant speed cont rol mode is automati-
cally canceled for any reasons other than the above, there may be a malfunction in the
system. Contact your Lexus dealer.
■Situations in which the curve speed
reduction function may not operate
In situations such as the following, the curve
speed reduction function may not operate:
●When the vehicle is being driven around
a gentle curve
●When the accelerato r pedal is being
depressed
●When the vehicle is being driven around
an extremely short curve
■Brake operation
A brake operation sound may be heard and
the brake pedal response may change, but
these are not malfunctions.
■Warning messages and buzzers for
dynamic radar cruise control with
full-speed range
Warning messages and buzzers are used to
indicate a system malfunction or to inform
the driver of the need for caution while driv-
ing. If a warning messa ge is shown on the
multi-information displa y, read the message
and follow the instructions. ( P.168, 346)
■When the sensor may not be correctly
detecting the vehicle ahead
In the case of the fo llowing and depending
on the conditions, operate the brake pedal
when deceleration of the system is insuffi-
cient or operate the accelerator pedal
when acceleration is required.
As the sensor may not be able to correctly
detect these types of vehicles, the approach
warning ( P.197) may not be activated.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving in the same
lane
●Vehicles with small rear ends (trailers
with no load on board, etc.)

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