brake LEXUS RCF 2019 Owner's Guide

250 4-5. Using the driving support systems
RC F_UPCS (Pre-Collision System) The pre-collision system uses a radar sensor and camera sensor to detect
vehicles and pedestrians in front of yo ur vehicle. When the system 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 possibility of a fr ontal collision with a vehicle or pedes-
trian 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 disabled/enabled and the warning timing can
be changed. (  P. 254)

2514-5. Using the driving support systems
4
Driving
RC F_U ◆ Pre-collision warning
When the system determines that
the possibility of a frontal collision is
high, a buzzer will sound and a warn-
ing message 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 po ssibility 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 po ssibility of a frontal collision is high,
the system warns the driver. If the syst em determines that the possibility of a
frontal collision is extremely high, the br akes are automatically applied to help
avoid the collision or reduce the collision speed.
◆ Suspension control (if equipped)
When the system determines that the po ssibility of a frontal collision is high,
the Adaptive Variable Suspension System (  P. 313) will control the damping
force of the shock absorbers to help ma intain an appropriate vehicle posture.
◆ Steering control (if equipped)
When the system determines that the possibility of a frontal collision is high
and the driver is operating the steering wheel, the LDH system (  P. 313) will
control the turning angle of the front an d rear wheels and effort necessary to
turn the steering wheel to help enhance steering responsiveness.

252 4-5. Using the driving support systems
RC F_U 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 sy stem instead of normal braking operations under any
circumstances. This system will not preven t collisions or lessen collision damage or
injury in every situation. Do not overly rely on this system. Failure to do so may lead to
an accident, resulting in death or serious injury. ●
Although this system is designed to help avoid a collision or help reduce the impact of
the collision, its effectivenes s 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 carefully. Do not overly rely on this system and always
drive carefully.
• Conditions under which the system may oper ate even if there is no possibility of a
collision:  P. 256
• Conditions under which the system may not operate properly:  P. 258●
Do not attempt to test the operation of the pre-collision system yourself, as the system
may not operate properly, possib ly leading to an accident.■
Pre-collision braking ●
When the pre-collision braking function is operating, a large amount of braking force
will be applied. ●
If the vehicle is stopped by the operation of the pre-collision braking function, the pre-
collision braking function operation will be canceled after approximately 2 seconds.
Depress the brake pedal as necessary. ●
The pre-collision braking fu nction may not operate if certain operations are per-
formed by the driver. If the accelerator pedal is being depressed strongly or the steer-
ing wheel is being turned, the system may de termine that the driver is taking evasive
action and possibly prevent the pre-coll ision braking function from operating.●
In some situations, wh ile the pre-collision braking function is operating, operation of
the function may be canceled if the accele rator pedal is depressed strongly or the
steering wheel is turned and the system de termines that the driv er is taking evasive
action. ●
If the brake pedal is being depressed, the sy stem may determine that the driver is tak-
ing evasive action and possibly delay the op eration timing of the pre-collision braking
function.

2554-5. Using the driving support systems
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Driving
RC F_U ■
Operational conditions
The pre-collision system is enabled and the sy stem determines that the possibility of a
frontal collision with a vehicle or pedestrian is high.
Each function is operationa l at the following speeds:●
Pre-collision warning:
• 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. ●
Pre-collision brake assist:
• Vehicle speed is between 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 battery terminal has been disconnected 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-collis ion warning function will be operational)■
Pedestrian detection function
■
Cancelation of the pre-collision braking
If either of the following occur while the pre-co llision braking function is operating, it will
be canceled: ●
The accelerator pedal is depressed strongly. ●
The steering wheel is turned sharply or abruptly.The pre-collision system detects pedestrians
based on the size, prof ile, and motion of a
detected object. However, a pedestrian may not
be detected depending on the surrounding
brightness and the motion, posture, and angle of
the detected object, preventing the system from
operating properly. (  P. 259)

2594-5. Using the driving support systems
4
Driving
RC F_U • 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 making 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 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 ca mera sensor is misaligned●
In some situations such as the following, sufficient braking forc e 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 system 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 ra in coat, long skirt, etc.), making their sil-
houette obscure
• Pedestrians who are carrying large baggage, 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 be hind a vehicle or a large object
• Pedestrians who are extremely close to the side of the vehicle (outside rear view
mirror, etc.)• If the front of the vehicle is raised or low-
ered

260 4-5. Using the driving support systems
RC F_U ■
If the PCS warning light flas hes or illuminates and a warning message is displayed on
the multi-inform ation display
The pre-collision system may be temporarily unavailable or there may be a malfunction
in the system. ●
In the following situations, the warning light will turn off, the message will disappear and
the system will become operational when normal operating conditions return:
• When the radar sensor or ca mera 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 dirt y or covered 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 (Defogging the windshield:
 P. 338)
• If the camera sensor is obstructed, such as when the hood is open or a sticker is
attached to the windshield near the camera sensor ●
If the PCS warning light continues to flash or remains illuminated or the warning mes-
sage does not disappear even though the vehicle has returned to normal, the system
may be malfunctioning. Have the vehicle in spected by your Lexus dealer immediately.■
If VSC is disabled ●
If VSC is disabled (  P. 315), the pre-collision brake a ssist and pre-collision braking
functions are also disabled. ●
The PCS warning light will turn on and “V SC Turned Off Pre-Collision Brake System
Unavailable” will be displayed on the multi-information display.

2714-5. Using the driving support systems
4
Driving
RC F_U This mode employs a radar sensor to detect the presence of vehicles up to
approximately 328 ft. (100 m) ahead, de termines the current vehicle-to-vehicle
following distance, and operates to main tain a suitable following distance from
the vehicle ahead. Note that vehicle-to-vehicle distance will cl ose 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 dis-
tance 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 sl ower than the set speed appearsWhen a vehicle is detected running ahead of you, the system automatically deceler-
ates 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). Th e 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 the system cannot
decelerate sufficie ntly to prevent your vehicle from closing in on the vehicle ahead.
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 reached. The system then returns to con-
stant speed cruising.Driving in vehicle-to-vehicle distance control mode
1
2
3

274 4-5. Using the driving support systems
RC F_U Pressing the switch changes the vehi-
cle-to-vehicle distance as follows:
Long
Medium
Short The vehicle-to-vehicle distance is set
automatically to long mode when the
engine switch is turned to IGNITION
ON mode.
If a vehicle is running ahead of you, the pr eceding vehicle mark w ill also be displayed.
Select a distance from the table below. Note that the distances shown corre-
spond to a vehicle speed of 50 mph (8 0 km/h). Vehicle-to-vehicle distance
increases/decreases in accord ance with vehicle speed.
Pulling the lever toward you cancels
the speed control. The speed control is also canceled when
the brake pedal is depressed.
Pushing the lever up resumes the
cruise control and returns vehicle
speed to the set speed. However, cruise control does not
resume when the vehicle speed is
approximately 25 mph (40 km/h) or
less.Changing the vehicle-to-vehicle distance (vehicle-to-vehicle distance
control mode) Preceding
vehicle mark1
2
3
Vehicle-to-vehicle distance settings (vehicle-to-vehicle distance con-
trol mode) Distance options Vehicle-to-vehicle distance
Long Approximately 160 ft. (50 m)
Medium Approximately 130 ft. (40 m)
Short Approximately 100 ft.(30 m)
Canceling and resuming the speed control 1
2

2754-5. Using the driving support systems
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Driving
RC F_U 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 vehicle-
to-vehicle distance. ■
Warnings may not occur when
In the following instances, warnings ma y not occur even when the vehicle-to-
vehicle distance is small. ●
When the speed of the preceding vehicle matches or exceeds your vehicle
speed ●
When the preceding vehicle is traveling at an extremely slow speed ●
Immediately after the crui se control speed was set●
When depressing the accelerator pedalApproach warning (vehicle-to-vehicle distance control mode)

278 4-5. Using the driving support systems
RC F_U ■
Automatic cancelation of co nstant speed control mode
Constant speed control mode is automatica lly canceled in the following situations:●
Actual vehicle speed is more than approxim ately 10 mph (16 km/h) below the set vehi-
cle speed. ●
Actual vehicle speed falls below approximately 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 . Contact your Lexus dealer.■
Warning messages and buzzers fo r dynamic radar cruise control
Warning messages and buzzers are used to indicate a system malfunction or to inform
the driver of the need for ca ution while driving. If a warn ing message is shown on the
multi-information display, read the message 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 insuff icient 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. 275) 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 (traile rs 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 detecting of
the sensor