brake LEXUS NX300H 2019 Service Manual

1974-5. Using the driving support systems
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Driving
4-5.Using the driving support systems
■PCS (Pre-Collision System)
 P.202
■LDA (Lane Departure Alert with
steering control)
 P.209
■Automatic High Beam
 P.185
■Dynamic radar cruise control with
full-speed range
 P.217
The pre-collision system is equipped with a sophisticated computer that will
record certain data, such as:
• Accelerator status
•Brake status
• Vehicle speed
• Operation status of the pre-collision
system functions
• Information (such as the distance and relative speed between your
vehicle and the vehicle ahead or
other objects)
• Images from the camera sensor (available only when the pre-colli-
sion braking function or the pre-col-
lision brake assist function was
operating)
The pre-collision system does not
record conversations, sounds or
images of the inside of the vehicle.
 Data usage
Lexus may use the data recorded in this
computer to diagnose malfunctions, con-
duct research and development, and
improve quality.
Lexus will not disclose the recorded data to
a third party except:
• With the consent of the vehicle owner or
with the consent of the lessee if the vehi-
cle is leased
• In response to an official request by the police, a court of law or a government
agency
• For use by Lexus in a lawsuit
• For research purposes where the data is not tied to a specific vehicle or vehicle
owner
 Recorded images can be erased
using a specialized device.
The image recording function can be dis-
Lexus Safety System+
The Lexus Safety System+ consists
of the following drive assist systems
and contributes to a safe and com-
fortable driving experience:
Drive assist systems of Lexus
Safety System+
WARNING
■Lexus Safety System+
The Lexus Safety System+ is designed to
operate under the assumption that the
driver will drive safely, and is designed to
help reduce the impact to the occupants
and the vehicle in the case of a collision
or assist the driver in normal driving con-
ditions.
As there is a limit to the degree of recog-
nition accuracy and control performance
that this system can provide, do not
overly rely on this system. The driver is
always responsible for paying attention
to the vehicle’s surro undings and driving
safely.
Vehicle data recording

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■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
When the system determines that the
possibility of a frontal collision is high,
the system warns the driver. If the sys-
tem determines that the possibility of a
frontal collision is extremely high, the
brakes are automatically applied to
help avoid the collision or reduce the
collision speed.
PCS (Pre-Collision System)
The pre-collision system uses a
radar sensor and camera sensor to
detect vehicles and pedestrians in
front of your vehicle. When the sys-
tem determines that the possibility
of a frontal collision with a vehicle
or pedestrian 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 determines that the possi-
bility of a frontal collision with a
vehicle or pedestrian is extremely
high, the brakes are automatically
applied to help avoid the collision
or help reduce the impact of the
collision.
The pre-collision system can be dis-
abled/enabled and the warning tim-
ing can be changed. ( P.204)
System functionsWARNING
■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.

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WARNING
●Although this system is designed to
help avoid a collision or help reduce
the impact of the coll ision, 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 following conditions care-
fully. 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.206
• Conditions under which the system may not operate properly: P.207
●Do not attempt to test the operation of
the pre-collision system yourself, as 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 accid ent or is malfunc-
tioning
●When the vehicle is driven in a sporty
manner or off-road
●When the tires are not properly
inflated
●When the tires are very worn
●When tires of a size other than speci-
fied are installed
●When tire chains are installed

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1 Far
The warning will begin to operate earlier
than with the default timing.
2Middle
This is the default setting.
3Near
The warning will begin to operate later
than with the default timing.
■Operational conditions
The pre-collision system is enabled and the
system determines that the possibility of a
frontal collision with a vehicle or pedestrian
is high.
Each function is operat ional at the following
speeds:
●Pre-collision warning:
• Vehicle speed is be tween approximately
7 and 110 mph (10 and 180 km/h). (For
detecting a pedestrian, vehicle speed is
between approximately 7 and 50 mph
[10 and 80 km/h].)
• The relative speed between your vehicle
and the vehicle or pedestrian ahead is
approximately 7 mph (10 km/h) or more.
●Pre-collision brake assist:
• Vehicle speed is be tween approximately
20 and 110 mph (30 and 180 km/h). (For
detecting a pedestrian, vehicle speed is
between approximately 20 and 50 mph
[30 and 80 km/h].)
• The relative speed between your vehicle and the vehicle or pedestrian ahead is
approximately 20 mph (30 km/h) or
more.
●Pre-collision braking:
• Vehicle speed is between approximately
7 and 110 mph (10 and 180 km/h). (For
detecting a pedestrian, vehicle speed is
between approximately 7 and 50 mph
[10 and 80 km/h].)
• The relative speed between your vehicle and the vehicle or pedestrian ahead is
approximately 7 mph (10 km/h) or more.
The system may not operate in the following
situations:
●If a 12-volt battery terminal has been dis-
connected and reconnected and then the
vehicle has not been driven for a certain
amount of time
●If the shift lever is in R
●If VSC is disabled (only the pre-collision
warning function wi ll be operational)
■Pedestrian detection function
The pre-collision system detects pedestri-
ans based on the size, profile, and motion of
a detected object. However, a pedestrian
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.207)
■Cancelation of the pre-collision braking
If either of the follo wing 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.

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changes suddenly,
such as at the entrance or exit of a tunnel
• When a very bright light, such as the sun
or the headlights of oncoming traffic,
shines directly in to the camera sensor
• When the surrounding area is dim, such
as at dawn or dusk, or while at night or in
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 camera sensor
• The vehicle is wobbling.
• The vehicle is being driven at extremely high speeds.
• When driving on a hill
• If the radar sensor or camera sensor is misaligned
●In some situations such 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
●Some pedestrians such as the following
may not be detected by the radar sensor
and camera sensor, preventing the sys-
tem from operating properly: • Pedestrians shorter than approximately
3.2 ft. (1 m) or taller than approximately
6.5 ft. (2 m)
• Pedestrians wearing oversized clothing (a rain coat, long skirt, etc.), making their
silhouette obscure
• Pedestrians who are carrying large bag- gage, holding an umbrella, etc., hiding
part of their body
• Pedestrians who are bending forward or squatting
• Pedestrians who are pushing a stroller,
wheelchair, bicycle or other vehicle
• Groups of pedestrians which are close together
• Pedestrians who are wearing white and look extremely bright
• Pedestrians in the dark, such as at night
or while in a tunnel
• Pedestrians whose clothing appears to be nearly the same color or brightness as
their surroundings
• Pedestrians near walls, fences, guardrails, or large objects
• Pedestrians who are on a metal object (manhole cover, steel plate, etc.) on the
road
• Pedestrians who are walking fast
• Pedestrians who are changing speed abruptly
• Pedestrians running out from behind a vehicle or a large object
• Pedestrians who are extremely close to
the side of the vehicle (outside rear view
mirror, etc.)
■If the PCS warning light flashes or illumi-
nates and a warning message is dis-
played on the multi-information display
The pre-collision system may be temporar-
ily unavailable or there may be a malfunc-
tion in the system.
●In the following situations, the warning
light will turn off, the message will disap-
pear and the system will become opera-
tional when normal operating conditions
return:
• When the radar sensor or camera sensor or the area around either sensor is hot,
such as in the sun
• When the radar sensor or camera sensor or the area around either sensor is cold,
such as in an extremely cold environment
• When a front sensor is dirty or covered

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with snow, etc.
• When the part of the windshield in front of the camera sensor is fogged up or cov-
ered with condensation or ice (Defog-
ging the windshield: P.267)
• If the camera sensor is obstructed, such
as when the hood is open or a sticker is
attached to the windshield near the cam-
era sensor
●If the PCS warning ligh t continues to flash
or remains illuminated or the warning
message does not disappear even
though the vehicle has returned to nor-
mal, the system may be malfunctioning.
Have the vehicle inspected by your Lexus
dealer immediately.
■If VSC is disabled
●If VSC is disabled ( P.251), 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.
■Lane departure alert function
When the system determines that the
vehicle might depart from its lane, a
warning is displayed on the multi-infor-
mation display, and either the warning
buzzer sounds or the steering wheel
vibrates to alert the driver.
When the warning buzzer sounds or the
steering wheel vibrates, check the sur-
rounding road situation and carefully oper-
ate the steering wheel to move the vehicle
back to the center of the lane.
LDA (Lane Departure Alert
with steering control)
When driving on highways and
freeways with white (yellow) lines,
this function alerts the driver when
the vehicle might depart from its
lane and provides assistance by
operating the steering wheel to
keep the vehicle in its lane.
The LDA system recognizes visible
white (yellow) lines with the camera
sensor on the upper portion of the
windshield.
Functions included in LDA sys-
tem

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This mode employs a radar sensor to detect the presence of vehicles up to approx-
imately 328 ft. (100 m) ahead, determines the current vehicle-to-vehicle following
distance, and operates to maintain a suit able following distance from the vehicle
ahead.
Note that vehicle-to-vehicle distance will close in when traveling on downhill slopes.
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehicle distance
can also be set by operating the vehicle-to-vehicle distance switch.
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, pushing the cruise control lever up or
depressing the accelerator pedal will resume follow-up cruising.
Example of acceleration
When there are no longer any preceding vehicles driving slower than the set
speed
The system accelerates until the set speed is re ached. The system then returns to constant
speed cruising.
Driving in vehicle-to-vehicle distance control mode
A
B
C

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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 control, 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.
However, when a vehicle ahead is not
detected, cruise control does not resume
when the vehicle speed is approximately
25 mph (40 km/h) or less.
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.
Distance optionsVehicle-to-vehicle distance
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 (vehicle-to-
vehicle distance control mode)

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●Vehicle speed is at or above approxi-
mately 30 mph (50 km/h).
However, when a preceding vehicle is
detected, the dynamic radar cruise con-
trol with full-speed range can be set even
if the vehicle speed is below approxi-
mately 30 mph (50 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
●Pushing the lever up while the vehicle
ahead stops will resume follow-up cruis-
ing if the vehicle ahead starts off within
approximately 3 seconds after the lever
is pushed up.
●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:
●Actual vehicle speed falls at or below
approximately 25 mph (40 km/h) when
there are no vehicles ahead.
●The preceding vehicle leaves the lane
when your vehicle is following at a vehicle
speed at or below approximately 25 mph
(40 km/h). Otherwise, the sensor can
not properly detect the vehicle.
(“CRUISE NOT AVAILABLE No pre-
ceding vehicle” is displayed on the multi-
information display.)
●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 other rea-
son, there may be a malfunction in the sys-
tem. 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 25 mph (40 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 other reason, there
may be a malfunction in the system. Con-
tact your Lexus dealer.
■Brake system operation sound
If the brakes are app lied automatically while
the vehicle is in vehicle-to-vehicle distance
control mode, a brake system operation
sound may be heard. This does not indicate
a malfunction.
■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

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and follow the instructions.
■When the sensor may not be correctly
detecting the vehicle ahead
In the case of the following 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
lane
●Vehicles with small rear ends (trailers
with no load on board, etc.)
●Motorcycles travelin g 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