brake LEXUS RX350 2015 Service Manual

2782-4. Using other driving systems
Pre-Collision System When the radar sensor detects the possib ility of a frontal collision, the pre-
collision system such as the brakes and seat belts are automatically
engaged to lessen impact as well as vehicle damage.
■ Pre-collision seat belts (front seat belts only) If the pre-collision sensor detects that a collision is unavoidable, the pre-
collision system will retract the seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses
control of the vehicle. (  P. 8 5 )
However, the system will not operate in the event of skidding when the
VSC system is disabled.
■ Pre-collision brake assist When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to how strongly the brake pedal is
depressed. The system may not warn the driver using a warning light,
warning display and buzzer when the system detects and judges braking
operations.
■ Pre-collision braking When there is a high possibility of a frontal collision, the system warns the
driver using a warning light, warnin g display and buzzer. If the system
determines that a collision is unavoidable, the brakes are automatically
applied to reduce the collision speed. Pre-collision braking can be dis-
abled using the pre-collision braking off switch.
 : If equipped

2802-4. Using other driving systems
■
The pre-collision system is operational when ●
Pre-collision seat belts (type A):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle
running ahead of you is greater than about 19 mph (30 km/h).
• The front occupants are wearing a seat belt.●
Pre-collision seat belts (type B):
• Vehicle speed is greater than about 19 mph (30 km/h).
• The system detects sudd en braking or skidding.
• The front occupants are wearing a seat belt.●
Pre-collision brake assist:
• Vehicle speed is greater than about 19 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle
running ahead of you is greater than about 19 mph (30 km/h).
• The brake pedal is depressed.●
Pre-collision braking:
• The pre-collision braking off switch is not pressed.
• Vehicle speed is greater than about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle
running ahead of you is greater than about 10 mph (15 km/h).

2812-4. Using other driving systems
2
When driving ■
Conditions that may trigger the system even if there is no possibility of collision ●
When there is an object by the roadside at the entrance to a curve●
When passing an oncoming vehicle on a curve●
When driving over a narrow iron bridge●
When there is a metal object on the road surface●
When driving on an uneven road surface●
When passing an oncoming vehicle on a left-turn●
When your vehicle rapidly closes on the vehicle in front●
When a grade separation/interchange, sign, billboard, or other structure
appears to be directly in the vehicle's line of travel●
When climbing a steep hill causes an over head billboard or ot her metallic struc-
ture to appear directly in the vehicle's line of travel●
When an extreme change in vehicle height occurs●
When the axis of the radar is out of adjustment●
When passing through certain toll gates●
When driving on a bridge●
When passing through a tunnel
When the system is activated in the situations described above, there is also a possi-
bility that the seat belts will retract quickly and the brakes will be applied with a force
greater than normal. When the seat belt is locked in the retracted position, stop the
vehicle in a safe place, release the seat belt and refasten it.

2842-4. Using other driving systems
CAUTION■
Limitations of the pre-collision system
Do not overly rely on the pre-collision system. Always drive safely, taking care to
observe your surroundings and checking for any obstacles or other road hazards.
Failure to do so may cause an accident resulting in death or serious injury.■
Cautions regarding the assist contents of the system
By means of alarms and brake control, the pre-collision system is intended to assist
the driver in avoiding collisions through the process of LOOK-JUDGE-ACT. There
are limits to the degree of assistance the system can provide, so please keep in mind
the following important points. ●
Assisting the driver in watching the road
The pre-collision system is only able to detect obstacles directly in front of the
vehicle, and only within a limited range. It is not a mechanism that allows careless
or inattentive driving, and it is not a system that can assist the driver in low-visibil-
ity conditions. It is still necessary for the driver to pay close attention to the vehi-
cle's surroundings.●
Assisting the driver in making correct judgment
When attempting to estimate the possibilit y of a collision, the only data available
to the pre-collision system is that from ob stacles it has detected directly in front of
the vehicle. Therefore, it is absolutely necessary for the driver to remain vigilant
and to determine whether or not there is a possibility of collision in any given situ-
ation.●
Assisting the driver in taking action
The pre-collision system's braking assist feature is designed to help reduce the
severity of a collision, and so only acts when the system has judged that a collision
is unavoidable. This system by itself is not capable of automatically avoiding a col-
lision or bringing the vehicl e to a stop safely. For this reason, when encountering a
dangerous situation the driver must take direct and immediate action in order to
ensure the safety of all involved.

2852-4. Using other driving systems
2
When driving CAUTION■
When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary in any of the following situations: ●
When water or snow thrown up by the surrounding vehicles hinders the function-
ing of the sensor●
When your vehicle is pointing upwards (caused by a heavy load in the luggage
compartment etc.)●
Vehicles that cut in suddenly●
Vehicles with small rear ends (tra ilers with no load on board etc.)●
Motorcycles traveling in the same lane■
Handling the radar sensor
Observe the following to ensure the pre-collision system can function effectively: ●
Keep the sensor and front grille clean at all times.
Clean the sensor and front grille with a so ft cloth so you do not mark or damage
them.●
Do not subject the sensor or surrounding area to a strong impact.
If the sensor moves even slightly off po sition, the system may become inaccurate
or malfunction. If the sensor or surround ing area is subject to a strong impact,
always have the area inspected an d adjusted by your Lexus dealer.●
Do not disassemble the sensor.●
Do not attach accessories or stickers to the sensor, grille or surrounding area.●
Do not modify or paint the sensor and grille cover.

2942-5. Driving information
CAUTION■
Off-road driving precautions
Always observe the following precautions to minimize the risk of death or serious
injury or damage to your vehicle: ●
Drive carefully when off the road. Do not take unnecessary risks by driving in
dangerous places.●
Do not grip the steering wheel spokes wh en driving off-road. A bad bump could
jerk the wheel and injure your hands. Keep both hands and especially your
thumbs on the outside of the rim.●
Always check your brakes for effectiveness immediately after driving in sand,
mud, water or snow.●
After driving through tall grass, mud, rock , sand, water, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped to the underbody.
Clear off any such matter from the underbody. If the vehicle is used with these
materials trapped or adhering to the underbody, a breakdown or fire could occur.●
When driving off-road or in rugged te rrain, do not drive at excessive speeds,
jump, make sharp turns, strike objects, etc. This may cause loss of control or vehi-
cle rollover causing death or serious injury. You are also risking expensive dam-
age to your vehicle’s suspension and chassis.
NOTICE■
To prevent water damage
Take all necessary safety measures to ensure that water damage to the engine or
other components does not occur. ●
Water entering the engine air intake will cause severe engine damage. ●
Water entering the automatic transmission will cause deterioration in shift quality,
locking up of your transmission accompanied by vibration, and ultimately dam-
age.
●
Water can wash the grease from wheel bearings, causing rusting and premature
failure, and may also enter the differentials, transmission and transfer case, reduc-
ing the gear oil’s lubricating qualities.

2952-5. Driving information
2
When driving NOTICE■
When you drive through water
If driving through water, such as when crossing shallow streams, first check the
depth of the water and the bottom of the stream for firmness. Drive slowly and avoid
deep water.■
Inspection after off-road driving ●
Sand and mud that has accumulated around brake discs may affect braking effi-
ciency and may damage brake system components.●
Always perform a maintenance inspection after each day of off-road driving that
has taken you through rough terrain, sand, mud, or water. For scheduled mainte-
nance information, refer to the “Warra nty and Services Guide/Owner’s Manual
Supplement/Schedul ed Maintenance”.

2982-5. Driving information
As shown in the example above, if the number of occupants increases,
the cargo and luggage load will be re duced by an amount that equals the
increased weight due to the addition al occupants. In other words, if an
increase in the number of occupants ca uses an excess of the total load
capacity (combined weight of occupants plus cargo and luggage load),
you must reduce the cargo and luggage on your vehicle. CAUTION■
Things that must not be carri ed in the luggage compartment
The following things may cause a fire if loaded in the luggage compartment: ●
Receptacles containing gasoline●
Aerosol cans■
Storage precautions
Observe the following precautions.
Failure to do so may result in death or serious injury. ●
Stow cargo and luggage in the lugga ge compartment whenever possible.●
Do not stack cargo and luggage in the luggage compartment higher than the
seatbacks.
Such items may be thrown about and possib ly injure people in the vehicle in the
event of sudden braking or in an accident.●
Do not place cargo or luggage in or on the following locations as the items may
get under the brake or accelerator pedal and prevent the pedals from being
depressed properly, block the driver’s vision, or hit the driver or passengers,
causing an accident:
• At the feet of the driver
• On the front passenger or rear seats (when stacking items)
• On the luggage cover
• On the instrument panel
•On the dashboard
●
Secure all items in the occupant compartment, as they may shift and injure some-
one in the event of sudden braking, sudden swerving or an accident.

3022-5. Driving information
Winter driving tips Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the ve hicle in a manner appropriate to the
prevailing weather conditions.
■ Pre-winter preparations
● Use fluids that are appropria te to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspec t the condition of the battery.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the front tires. Ensure that all tires are the same size and brand, and that chains match
the size of the tires.
■ Before driving the vehicle
Perform the following accord ing to the driving conditions:
● Do not try to forcibly open a w indow or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To ensure proper operation of the climate control system fan,
remove any snow that has accumu lated on the air inlet vents in
front of the windshield.
● Check for and remove any exce ss ice or snow that may have
accumulated on the exterior lights, vehicle's roof, chassis, around
the tires or on the brakes.
● Remove any snow or mud from the bottom of your shoes before
getting in the vehicle.

3032-5. Driving information
2
When driving
Selecting tire chains
Use the correct tire chain size when mounting the tire chains. Chain size
is regulated for each tire size.
Side chain:
0.12 in. (3 mm) in diameter
0.98 in. (25 mm) in length
0.43 in. (10.8 mm) in width
Cross chain:
0.15 in. (3.9 mm) in diameter
1.00 in. (25.3 mm) in length
0.54 in. (13.8 mm) in width
Regulations on the use of tire chains
Regulations regarding the use of tire chains vary depending on location
and type of road. Always check local regulations before installing chains. ■ When driving the vehicle
Accelerate the vehicle slowly, keep a safe distance between you and
the vehicle ahead, and drive at a reduced speed suitable to road
conditions.
■ When parking the vehicle
Park the vehicle and move the shif t lever to P without setting the
parking brake. The parking brake may freeze up, preventing it from
being released. If necessary, bl ock the wheels to prevent inadvert-
ent sliding or creeping.