brakes LEXUS RX450h 2018 User Guide

236 4-1. Before driving
RX450h_RX450hL _U_OM48F85UWARNING ■
Hitch
Trailer hitch assemblies have different weight capacities established by the hitch manu-
facturer. Even though the vehicle may be phys ically capable of towing a higher weight,
the operator must determine the maximum weight rating of the particular hitch assem-
bly and never exceed the maximum weight rating specified for the trailer-hitch.
Exceeding the maximum weight rating set by the trailer-hitch manufacturer can cause
an accident resulting in death or serious personal injuries. ■
When towing a trailer
Lexus recommends trailers with brakes that conform to any applicable federal and
state/provincial regulations. ●
If the gross trailer weight exceeds unbraked TWR, trailer brakes are required. Lexus
recommends trailers with brakes that conform to all applicable federal and state/pro-
vincial regulations. ●
Never tap into your vehicle’s hydraulic system, as this will lower the vehicle’s braking
effectiveness. ●
Never tow a trailer without using a safety chain securely attached to both the trailer
and the vehicle. If damage occurs to the co upling unit or hitch ball, there is danger of
the trailer wandering into another lane.
NOTICE ■
When installing a trailer hitch
Use only the position recommended by your Lexus dealer. Do not install the trailer
hitch on the bumper; this may cause body damage. ■
Do not directly splice trailer lights
Do not directly splic e trailer lights. Directly splicin g trailer lights may damage your
vehicle’s electrical system and cause a malfunction.

256 4-2. Driving procedures
RX450h_RX450hL _U_OM48F85UTurns the brake hold system on The brake hold standby indicator
(green) comes on. Wh ile the system is
holding the brakes, the brake hold oper-
ated indicator (yellow) will illuminate. ■
Brake hold system operating conditions
The brake hold system cannot be turn ed on in the following conditions:●
The driver’s door is not closed. ●
The driver’s seat seat belt is not buckled.
If either of the conditions above are detected when the brake hold system is enabled, the
system will turn off and the brake hold standby in dicator light will go off. In addition, if any
of the conditions are detected while the sy stem is holding the brakes, a warning buzzer
will sound and a message will be shown on th e multi-information di splay. The parking
brake will then be set automatically. ■
Brake hold function ●
If the brake pedal is left released for a pe riod of about 3 minutes after the system has
started holding the brakes, the parking brake will be set automatically. In this case, a
warning buzzer sounds and a message is shown on the multi- informatio n display.●
To turn the system off while the system is holding the brakes, firmly depress the brake
pedal and press the switch again. ●
The brake hold function may not hold the vehicle when the vehicle is on a steep incline.
In this situation, it may be necessary for the driver to apply the brakes. A warning
buzzer will sound and the mult i-information display will info rm the driver of this situa-
tion. If a warning message is shown on the multi-information display, read the message
and follow the instructions.Brake Hold The brake hold system keeps the brake appl ied when the shift lever is in D, S or
N with the system on and the brake peda l has been depressed to stop the vehi-
cle. The system releases the brake wh en the accelerator pedal is depressed
with the shift lever in D or S to allow smooth start off.

2574-2. Driving procedures
4
Driving
RX450h_RX450hL _U_OM48F85U■
When the parking brake is set automatically while the system is holding the brakes
Perform any of the following operat ions to release the parking brake.●
Depress the accelerator pedal. (The parking brake will not be released automatically if
the seat belt is not fastened.) ●
Operate the parking brake switch with the brake pedal depressed.
Make sure that the parking brake indicator light goes off. ( → P. 253) ■
When an inspection at your Lexus dealer is necessary
When the brake hold standby indicator (green) does not illu minate even when the brake
hold switch is pressed with the brake hold system operating conditions met, the system
may be malfunctioning. Ha ve the vehicle inspected at your Lexus dealer. ■
If “Brake Hold Fault Depress Brake to Deacti vate Visit Your Dealer” is displayed on the
multi-information display
The system may be malfunctioning. Have th e vehicle inspected by your Lexus dealer.■
Warning messages and buzzers
Warning messages and buzzers are used to indicate a system malfunction or to inform
the driver of the need for caution. If a warn ing message is shown on the multi-information
display, read the message and follow the instructions.■
If the brake hold operated indicator flashes
→ P. 660
WARNING ■
When the vehicle is on a steep incline
When using the brake hold system on a steep incline exercise caution. The brake hold
function may not hold the vehicle in such a situation. ■
When stopped on a slippery road
The system cannot stop the vehicle when the gripping ability of the tires has been
exceeded. Do not use the system when stopped on a slippery road.
NOTICE ■
When parking the vehicle
The brake hold system is not designed for use when parking the vehicle for a long
period of time. Turning the power switch off while the system is holding the brakes may
release the brakes, which would cause the vehicle to move. When operating the power
switch, depress the brake pedal, shift the shift lever to P and set the parking brake.

286 4-5. Using the driving support systems
RX450h_RX450hL _U_OM48F85UPCS (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 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. 290)

2954-5. Using the driving support systems
4
Driving
RX450h_RX450hL _U_OM48F85U• 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 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

3094-5. Using the driving support systems
4
Driving
RX450h_RX450hL _U_OM48F85UThis 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
1
2
3

3394-5. Using the driving support systems
4
Driving
RX450h_RX450hL _U_OM48F85U●
Vehicles with a navigation system (12.3-inch display): If the intuit ive parking assist dis-
play is set to on, detected objects will also be displayed on the panoramic view monitor.
For details, refer to “NAVIGATION SYSTEM OWNER’S MANUAL”. ■
Sensor detectio n information●
The sensor’s detection areas are limited to the areas around the vehicle’s bumper. ●
Certain vehicle conditions and the surrounding environment may affect the ability of a
sensor to correctly detect an object. Particular instances where this may occur are
listed below.
• There is dirt, snow or ice on the sensor . (Wiping the sensors will resolve this prob-
lem.)
• The sensor is frozen. (Thawing th e area will resolve this problem.)
In especially cold weather, if a sensor is frozen the screen may show an abnormal
display, or obstacles may not be detected.
• The sensor is covered in any way.
• The vehicle is leaning considerably to one side.
• When a sensor or the area around a sensor is extremely hot or cold.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• The vicinity of the vehicle is noisy due to vehicle horns, motorcycle engines, air
brakes of large vehicles, or other loud noises producing ultrasonic waves.
• There is another vehicle equipped with parking assist sensors in the vicinity.
• The sensor is coated with a sheet of spray or heavy rain.
• The bumper or sensor re ceives a strong impact.
• If the vehicle is significantly tilted.
• The vehicle is approaching a tall or curved curb.
• In harsh sunlight or intense cold weather.
• The area directly under the bumpers is not detected.
• If objects draw too close to the sensor.
• People may not be detected if they are wearing certain types of clothing.
In addition to the examples above, there ar e instances in which, because of their shape,
signs and other objects may be judged by a sensor to be closer than they are. ●
The shape of the object may prevent a sensor from detecting it. Pay particular attention
to the following objects:
• Wires, fences, ropes, etc.
• Cotton, snow and other materi als that absorb sound waves
• Sharply-angled objects
• Low obstacles
• Tall obstacles with upper sections projecting outwards in the direction of your vehi-
cle ●
The following situations may occur during use.
• Depending on the shape of the object and other factors, the detection distance may
shorten, or detectio n may be impossible.
• Objects may not be detected if they are too close to the sensor.
• There will be a short dela y between object detection and display. Even at slow
speeds, there is a possibility that the obje ct will come within the sensor’s detection
areas before the display is shown and the buzzer sounds.
• Thin posts or objects lower than the sens or may not be detected when approached,
even if they have been detected once.
• It might be difficult to hear beeps due to th e volume of audio system or air flow noise
of the air conditioning system.

3474-5. Using the driving support systems
4
Driving
RX450h_RX450hL _U_OM48F85UIf the Intelligent Clearance Sonar function detects that a collision with a wall or
other stationary object is possible, the hy brid system output will be restricted to
restrain any increase in the vehicle speed . (Hybrid system outp ut restriction con-
trol: See A below.)
Additionally, if the accelerator pedal continues to be depressed, the brakes will
be applied automatically to reduce the vehicle speed. (Brake control: See B
below.)Intelligent Clearance Sonar function

3514-5. Using the driving support systems
4
Driving
RX450h_RX450hL _U_OM48F85U■
Situations in which the Intelligent Clearance Sonar function may operate even if there
is no possibility of a collision
In some situations such as the following, the Intelligent Clearanc e Sonar function may
operate even though there is no possibility of a collision. ●
Vehicle surroundings
• When driving toward a banner, flag, low- hanging branch or boom barrier (such as
those used at railroad crossing s, toll gates and parking lots).
• When driving on a narrow path surrounded by a structure, such as in a tunnel or on
an iron bridge
• When parallel parking
• When there is a rut or hole in the surface of the road
• When driving on a metal cover (grating), such as those used for drainage ditches
• When driving on a steep slope
• If a sensor is hit by a large amount of wa ter, such as when driving on a flooded road●
Weather
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the system will return to
normal)
• If heavy rain or water strikes a sensor
• When driving in inclemen t weather such as fog, snow or a sandstorm●
Other ultrasonic waves sources
• When vehicle horns, vehicle detectors, motorcycle engines, air brakes of large vehi-
cles, the clearance sonar of other vehicles or other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic component, su ch as a backlit license plate (especially flu-
orescent type), fog lights, a fender pole or wireless antenna is installed near a sensor●
Changes in the vehicle posture
• If the vehicle is significantly tilted
• If the front of the vehicle is raised or lowered due to the carried load
• If the orientation of a sens or has been changed due to a collision or other impact• When driving on a narrow road
• When driving on a gravel road or in an
area with tall grass

352 4-5. Using the driving support systems
RX450h_RX450hL _U_OM48F85U■
If the Intelligent Clearance Sonar function operates unnecessarily such as at a railroad
crossing
Even in the event that the Intelligent Cleara nce Sonar function operates unnecessarily,
such as at a railroad crossing, brake cont rol will be canceled afte r approximately 2 sec-
onds, allowing you to proceed forward and leave the area, Brake control can also be
canceled by depressing the brake pedal. Depressing the accelerator pedal again will
allow you to proceed forward and leave the area. ■
Situations in which the Intelligent Cleara nce Sonar Brake function may not operate
properly
In some situations such as the following , this function may not operate properly.●
Weather
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the system will return to
normal)
• If heavy rain or water strikes a sensor
• When driving in inclemen t weather such as fog, snow or a sandstorm●
Vehicle surroundings
• When an object that cannot be detected is between the vehicle and a detected
object
• If an object such as a vehicle, motorcycle, bicycle or pedestrian cuts in front of the
vehicle or runs out from the side of the vehicle. ●
Other ultrasonic waves sources
• When vehicle horns, vehicle detectors, motorcycle engines, air brakes of large vehi-
cles, the clearance sonar of other vehicles or other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic component, su ch as a backlit license plate (especially flu-
orescent type), fog lights, a fender pole or wireless antenna is installed near a sensor●
Changes in the vehicle posture
• If the vehicle is significantly tilted
• If the front of the vehicle is raised or lowered due to the carried load
• If the orientation of a sens or has been changed due to a collision or other impact• When a sensor or the area around a sen-
sor is extremely hot or cold
• When strong winds are blowing