2019 LEXUS RCF brake sensor

226 4-3. Operating the lights and wipers
RC F_U With the headlights on, push the
lever away from you to turn on the
high beams. Pull the lever toward you to the center
position to turn the high beams off.
Pull the lever toward you and release
it to flash the high beams once. You can flash the high beams with the
headlights on or off. ■
Daytime running light system ●
The daytime running lights illuminate using th e same lights as the parking lights and illu-
minate brighter than the parking lights. ●
To make your vehicle more visible to other drivers during daytime driving, the daytime
running lights turn on automatically when a ll of the following conditions are met. (The
daytime running lights are not designed for use at night.)
• The engine is running
• The parking brake is released
• The headlight switch is in the (Canada only), or
* position
* : When the surroundings are bright
The daytime running lights remain on after they illuminate, even if the parking brake is set
again. ●
For the U.S.A.: Daytime running lights can be turned off by operating the switch.●
Compared to turning on the headlights, the daytime running light system offers greater
durability and consumes less electricity, so it can help improve fuel economy.●
Vehicles with LED front turn signal lights: If a turn signal light is in use, the daytime run-
ning light, on the same side, is turned off. For emergency flashers, both are turned off. ■
Headlight control sensorTurning on the high beam headlights 1
2
The sensor may not function properly if an
object is placed on the sensor, or anything that
blocks the sensor is affixed to the windshield.
Doing so interferes with the sensor detecting
the level of ambient li ght and may cause the
automatic headlight system to malfunction.

246 4-5. Using the driving support systems
RC F_U 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 an d relative speed between your vehicle
and the vehicle ahead or other objects)
• Images from the camera sensor (available only when the pre-collision braking
function or the pre-collision brake assist function was operating)
The pre-collision system does not record co nversations, sounds or images of the
inside of the vehicle. ●
Data usage
Lexus may use the data recorded in this computer to diagnose malfunctions,
conduct research and develo pment, 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 vehicle is leased
• In response to an official request by the police, a court of law or a govern-
ment 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 disa bled. However, if the function is dis-
abled, data from when the pre-collision system operates will not be available.Vehicle data recording

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)

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

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

2794-5. Using the driving support systems
4
Driving
RC F_U ■
Conditions under which the ve hicle-to-vehicle distance co ntrol mode may not function
correctly
In the case of the following conditions, o perate the brake pedal (or accelerator pedal,
depending on the situ ation) as necessary.
As the sensor may not be able to correctly detect vehicles ahead, the system may not
operate properly.
●
When the vehicle ahead of you decelerates suddenly ●
When your vehicle is pointing upwards
(caused by a heavy load in the luggage com-
partment, etc.) ●
Preceding vehicle has an extremely high
ground clearance
●
When the road curves or when the lanes are
narrow
●
When steering wheel operation or your posi-
tion in the lane is unstable