brake Lexus GX460 2012 Service Manual

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2-4. Using other driving systems
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■The pre-collision system is operational when
●Pre-collision warning
• Vehicle speed is greater than about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or oncomingvehicle is greater than about 10 mph (15 km/h).
●Pre-collision seat belts (linked to the radar sensor):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming
vehicle is greater than about 19 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (linked to brake operation):
• Vehicle speed greater than about 19 mph (30 km/h).
• The system detects sudden 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).
●AVS (Adaptive Variable Suspension System) control (if equipped):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehiclerunning ahead of you is greater than about 19 mph (30 km/h).

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●Pre-collision alert braking (vehicle with driver monitor system):
• The pre-collision braking off switch is not pressed.
• The system determines that the driver is not facing forward.
• Vehicle speed is greater than about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehiclerunning ahead of you is greater than about 25 mph (40 km/h).
■Conditions that may trigger the system even if there is no possibility of a 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 overhead billboard or other metallic struc-
ture to appear directly in the vehicle’s line of travel
●When there are excessive changes in the vehicle height (when it tilts forwards
or backwards)
●When there is an abnormality in the radar sensor
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 restricted position, stop the
vehicle in a safe place, release the seat belt and refasten it.

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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.
■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 likelihood of a collision, the only data available
to the pre-collision system is that from obstacles 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 vehicle to a stop safety. 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.

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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 (trailers 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 cover clean at all times.
Clean the sensor and front grille cover with a soft 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 position, the system may malfunction. If the
sensor or surrounding area is subject to a strong impact, always have the area
inspected and adjusted by your Lexus dealer.
●Do not disassemble the sensor.
●Do not attach accessories or stickers to the sensor, grille cover or surrounding
area.
●Do not modify or paint the sensor and grille cover.

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2-5. Driving information
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CAUTION
■Off-road driving precautions
Always observe the following precautions to minimize the risk of death, 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 when 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, rivers, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped on 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 terrain, 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.

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When driving
GX460_U.S.A. (OM60J00U)
NOTICE
■To prevent the 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.
■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 riverbed for firmness. Drive slowly and
avoid deep water.
■Inspection after off-road driving
●Sand and mud that has accumulated in brake drums and around brake discs may
affect braking efficiency 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 “Warranty and Services Guide”, “Owner’s Manual
Supplement” or “Scheduled Maintenance”.

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CAUTION
■Storage precautions
Observe the following precautions.
Failure to do so may result in death or serious injury.
●Stow cargo and luggage in the luggage compartment whenever possible.
●Do not stack cargo and luggage in the luggage compartment higher than the
seatbacks.
Such items may be thrown about and possibly injure people in the vehicle in the
event of a sudden braking, sudden swerving or an accident.
●Do not place cargo or luggage in or on the following locations as the item 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 a sudden braking, sudden swerving or an accident.
●When you fold down the rear seats, long items should not be place directly
behind the front seats.
●Never allow anyone to ride in the luggage compartment. It is not designed for
passengers. They should ride in their seats with their seat belts properly fastened.
Otherwise, they are much more likely to suffer death or serious bodily injury, in
the event of sudden braking or an accident.
■Roof luggage carrier precautions
To use the roof rails as a roof luggage carrier, you must fit the roof rails with two or
more genuine Lexus cross rails or their equivalent.
Follow the manufacturer’s instructions and precautions when installing the cross
rails or their equivalent.

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Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■Pre-winter preparations
●Use fluids that are appropriate to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific gravity of
battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the rear 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 according to the driving conditions:
●Do not try to forcibly open a window 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 accumulated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumulated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.

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GX460_U.S.A. (OM60J00U)
Selecting tire chainsUse the correct tire chain size when mounting the tire chains.
Chain size is regulated for each tire size. Side chain:Side chain
(0.20 in. [5 mm] in diameter)
Cross chain
(0.25 in. [6.3 mm] in diameter)
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 and drive at a reduced speed suitable
to road conditions.
■ When parking the vehicle
Park the vehicle and move the shift lever to P without setting the
parking brake. The parking brake may freeze up, preventing it from
being released. If necessary, block the wheels to prevent inadvert-
ent sliding or creeping.

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Trailer towing
Your vehicle is designed primarily as a passenger-and-load-carrying vehi-
cle. Towing a trailer can have an adverse impact on handling, performance,
braking, durability, and fuel consumption. For your safety and the safety of
others, you must not overload your vehicle or trailer. You must also ensure
that you are using appropriate towing equipment, that the towing equip-
ment has been installed correctly and used properly, and that you employ
the requisite driving habits.
Vehicle-trailer stability and braking performance are affected by trailer
stability, brake performance and setting, trailer brakes, the hitch and hitch
systems (if equipped).
To tow a trailer safely, use extreme care and drive the vehicle in accor-
dance with your trailer’s characte ristics and operating conditions.
Lexus warranties do not apply to dama ge or malfunction caused by towing
a trailer for commercial purposes.
Contact your Lexus dealer for further information about additional
requirements such as towing kits, etc.