brake LEXUS RX350 2019 Workshop Manual

2854-5. Using the driving support systems
4
Driving
RX350/RX350L_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. 289)

2894-5. Using the driving support systems
4
Driving
RX350/RX350L_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

290 4-5. Using the driving support systems
RX350/RX350L_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. 513)
• 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. 381), the pre-collision brake assist 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.

3034-5. Using the driving support systems
4
Driving
RX350/RX350L_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.
When the vehicle ahead of you stops, your vehicle will also stop (vehicle is stopped by
system 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 reached. The system then returns to con-
stant speed cruising.Driving in vehicle-to-vehicle distance control mode
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3074-5. Using the driving support systems
4
Driving
RX350/RX350L_U 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.
Pulling the lever toward you 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.)
Pushing 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.Resuming follow-up cruising when the vehicle has been stopped by sys-
tem control (vehicle-to-vehicle distance control mode)
Canceling and resuming the speed control 1
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308 4-5. Using the driving support systems
RX350/RX350L_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)

310 4-5. Using the driving support systems
RX350/RX350L_U ■
Dynamic radar cruise control with full-speed range can be set when ●
The shift lever is in the D or range 4 or higher of S has been selected.
(vehicles without paddle shift switches) ●
The shift lever is in D.
(vehicles with padd le shift switches)●
Range 4 or higher of D has been selected by using the paddle shift switch.
(vehicles with padd le shift switches)●
Vehicle speed is at or abov e approximately 30 mph (50 km/h). However, when a pre-
ceding vehicle is detected, the dynamic ra dar cruise control with full-speed range can
be set even if the vehicle speed is below approximately 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 vehicle-to-vehicle distance control mode, the vehi-
cle speed may decrease below the set speed in order to maintain the distance to the pre-
ceding vehicle. ■
When the vehicle stops while follow-up cruising ●
Pushing the lever up while the vehicle ahead stops will resume follow-up cruising if the
vehicle ahead starts off within approximat ely 3 seconds after the switch is pressed.●
If the vehicle ahead starts off within 3 seco nds after your vehicle stops, follow-up cruis-
ing will be resumed. ■
Automatic cancelation of vehicle- to-vehicle distance control mode
Vehicle-to-vehicle distance control mode is automatically canceled in the following situ-
ations. ●
Actual vehicle speed falls below approximately 25 mph (40 km/h) when there are no
vehicles ahead. ●
The preceding vehicle leaves the lane when yo ur vehicle is following at a vehicle speed
at or below approximately 25 mph (40 km/h ). Otherwise, the sensor cannot properly
detect the vehicle. (“Radar Cruise Contro l Not Available No Preceding Vehicles” 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 control:
• 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 th e system. Contact your Lexus dealer.

3114-5. Using the driving support systems
4
Driving
RX350/RX350L_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 for dynamic ra dar 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 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. 308) 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.)

312 4-5. Using the driving support systems
RX350/RX350L_U ●
Motorcycles travelin g in the same lane●
When water or snow thrown up by the surrounding vehicles hinders the detecting of
the sensor
■
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

3214-5. Using the driving support systems
4
Driving
RX350/RX350L_U The RCTA function uses radar sensors to detect vehicles approaching from the
right or left at the rear of the vehicle an d alerts the driver of the presence of such
vehicles by flashing the outside rear view mirror indicators and sounding a
buzzer.
Approaching vehicles
Detection areas of approaching vehicles ■
Rear Cross Traffic Auto Brake function (if equipped)
When the Intelligent Clearance Sonar wi th Rear Cross Traffic Auto Brake is
enabled and a vehicle approaching from the right or left at the rear of the vehi-
cle is detected, the Rear Cross Traffic Auto Brake function will perform brake
control to reduce the likelihood of an impact with the approaching vehicle.
Intelligent Clearance Sonar with Re ar Cross Traffic Auto Brake:  P. 336RCTA function
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