2019 LEXUS UX250H brake

1984-5. 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.
PCS (Pre-Collision System)
The pre-collision system uses a
radar sensor and front camera to
detect objects ( P.198) 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.200)
Detectable objects
System functions
WARNING
■Limitations of the pre-collision system
●The driver is solely responsible for safe
driving. Always drive safely, taking
care to observe your surroundings. Do
not use the pre-collision system
instead of normal braking operations
under any circumstances. This system
will not prevent collisions or lessen col-
lision damage or injury in every situa-
tion. Do not overly rely on this system.
Failure to do so may lead to an acci-
dent, resulting in death or serious
injury.

1994-5. Using the driving support systems
4
Driving
WARNING
●Although this system is designed to
help avoid a collision or help reduce
the impact of the collision, its effective-
ness may change according to various
conditions, therefore the system may
not always be able to achieve the same
level of performance. Read the follow-
ing conditions carefully. Do not overly
rely on this system and always drive
carefully.
• Conditions under which the system may operate even if there is no possi-
bility of a collision: P.202
• Conditions under which the system may not operate properly: P.203
●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 operat ion timing of the
pre-collision braking function.
■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
●When the vehicle is raised on a lift with
the hybrid system on and the tires are
allowed to rotate freely
●When inspecting the vehicle using a
drum tester such as a chassis dyna-
mometer or speedometer tester, or
when using an on vehicle wheel bal-
ancer
●When a strong impact is applied to the
front bumper or front grille, due to an
accident or other reasons
●If the vehicle cannot be driven in a sta-
ble manner, such as when the vehicle
has been in an accident or is malfunc-
tioning
●When the vehicle is driven in a sporty
manner or off-road
●When the tires are not properly
inflated

2014-5. Using the driving support systems
4
Driving
Each function is operational at the following speed
●Pre-collision warning
●Pre-collision brake assist
●Pre-collision braking
The system may not operate in the following situations:
●If a 12-volt battery terminal has been disco nnected 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 illuminated (only the pre-collision warning function will
be operational)
■Object detection function
The system detects ob jects based on their
size, profile, motion, etc. However, an object
may not be detected depending on the sur-
rounding brightness and the motion, pos-
ture, and angle of the detected object,
preventing the system from operating prop-
erly. ( P.203) The illustration shows an
image of detectable objects.
■Cancelation of the pre-collision braking
If either of the follo wing occur while the
Detectable objectsVehicle speedRelative speed between your
vehicle and object
VehiclesApprox. 7 to 110 mph (10 to
180 km/h)Approx. 7 to 110 mph (10 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
VehiclesApprox. 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)
Detectable objectsVehicle speedRelative speed between your vehicle and object
VehiclesApprox. 7 to 110 mph (10 to
180 km/h)Approx. 7 to 110 mph (10 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)

2044-5. Using the driving support systems
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.257), the pre-col-
lision brake assist and pre-collision brak-
ing 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.

2194-5. Using the driving support systems
4
Driving
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 sy stem 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, pressing the “+RES” switch or depressing
the accelerator pedal (start-off operation) will resume follow-up cruising. If the start-off
operation is not performed, system contro l continues to keep your vehicle stopped.
When the turn signal lever is operated and your vehicle moves to a left lane while driving at
50 mph (80 km/h) or more, the vehicle will quickly accelerate to help to overtake a pass-
ing vehicle.
Example of acceleration
Driving in vehicle-to-vehicle distance control mode
A
B
C

2224-5. Using the driving support systems
After the vehicle ahead of you starts
off, press the “+RES” switch.
Your vehicle will also resume follow-up
cruising if the accelerator pedal is
depressed after the vehicle ahead of
you starts off.1
Pressing the cancel switch cancels
the speed control.The speed control is also canceled when
the brake pedal is depressed.
(When the vehicle has been stopped by
system control, depressing the brake pedal
does not cancel the setting.)
2Pressing the “+RES” switch
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.
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.
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)
Distance optionsVehicle-to-vehicle distanceCanceling and resuming the
speed control
Approach warning (vehicle-to-
vehicle distance control mode)

2244-5. Using the driving support systems
below approximately 20 mph [30 km/h],
the set speed will be set to approximately
20 mph [30 km/h].)
■Accelerating after setting the vehicle
speed
The vehicle can accelerate by operating the
accelerator pedal. After accelerating, the
set speed resumes. However, during vehi-
cle-to-vehicle distance control mode, the
vehicle speed may decrease below the set
speed in order to maintain the distance to
the preceding vehicle.
■When the vehicle stops while follow-up
cruising
●Pressing the “+RES” switch while the
vehicle ahead stops w ill resume follow-up
cruising if the vehicle ahead starts off
within approximately 3 seconds after the
switch is pressed.
●If the vehicle ahead starts off within 3 sec-
onds after your vehicle stops, follow-up
cruising will be resumed.
■Automatic cancelation of vehicle-to-
vehicle distance control mode
Vehicle-to-vehicle dist ance control mode is
automatically canceled in the following situ-
ations.
●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.
●Pre-collision braking is activated.
●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.
●Pre-collision braking is activated.
If constant speed control mode is automati-
cally canceled for any reasons other than
the above, there may be a malfunction in the
system. Contact your Lexus dealer.
■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.196, 395)
■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.222) may not be activated.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving in the same

2254-5. Using the driving support systems
4
Driving
lane
●Vehicles with small rear ends (trailers
with no load on board, etc.)
●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 vehicle-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