brake Lexus GX470 2004 Engine / LEXUS 2004 GX470 FROM JAN. 2004 THROUGH JUL. 2004 PROD. (OM60A87U) Service Manual

STARTING AND DRIVING
419
Brake assist system
When you slam the brakes on, the brake assist system
judges as an emergency stop and provides more powerful
braking for a driver who cannot hold down the brake pedal
firmly.
When you slam the brakes on, more powerful braking will be
applied. At this time, you may hear a sound in the engine
compartment and feel the vibrations of the brake pedal. This
does not indicate a malfunction.
The brake assist system becomes operative after the vehicle
has accelerated to a speed in excess of approximately 10 km/h
(6 mph). It stops operating when the vehicle decelerates to a
speed below approximately 5 km/h (3 mph).
The brake assist system may not work for about 60 seconds
after the engine is started.
For an explanation of this system's warning light, see ABS
warning lightº on page 58.
Drum-in-disc type parking brake system
Your vehicle has a drum-in-disc type parking brake system.
This type of brake system needs bedding-down of the brake
shoes periodically or whenever the parking brake shoes and/or
drums are replaced.
Have your Lexus dealer perform the bedding-down.
TIRE PRESSURE WARNING SYSTEM
The tire pressure warning system is designed to provide
warning when tire inflation pressure of one or more of
your tires (including the spare tire) is low. The low tire
pressure warning light comes on to inform you that low
tire inflation pressure may hamper driving.

Low tire pressure warning light
This light comes on when the ignition key is turned to the ONº
position. It goes off after a few seconds. This indicates that the
tire pressure warning system is functioning properly.

STARTING AND DRIVING
420If the low tire pressure warning light comes on or blinks,
do the following.
If the warning light comes on:
Stop your vehicle in a safe place as soon as possible and
check that the inflation pressure of all tires (including the
spare tire) is as specified on the tire and loading
information
label. (See Checking tire inflation pressureº
on page 559.) If the warning light comes on even after tire
inflation pressure adjustment, you may have a flat tire. If
you have a flat tire, replace it with the spare tire. For
details, see If you have a flat tireº on page 469.
The warning light goes off a few minutes after air is put into the
deflated tire.
This warning light may turn on due to natural causes such as
natural air leaks or tire pressure changes caused by
temperature. In this case, adjusting the tire pressure will turn
off the warning light.
CAUTION
When the low tire pressure warning light comes on,
observe the following instructions:
 Depending on the conditions, reduce to an
appropriate speed as soon as possible.
 Adjust the tire pressure to the specified level as soon
as possible.
 Avoid abrupt steering wheel maneuvering and
braking. Tire deterioration may reduce steering
wheel control and brake effectiveness. This may lead
to serious injury or death.
 The tire pressure warning system may not activate
immediately if sudden bursts of air leakage occur.

STARTING AND DRIVING
428
BRAKE PAD WEAR LIMITINDICATORSThe brake pad wear limit indicators on your disc brakes
give a warning noise when the brake pads are worn to the
extent that replacement is required.
If you hear a squealing or scraping noise while driving, have the
brake pads checked and replaced by your Lexus dealer as
soon as possible. Expensive rotor damage can result if the
pads are not replaced when needed.

DRIVING TIPS
433
OPERATION IN FOREIGNCOUNTRIES
If you plan to drive your Lexus in another country...
First, comply with the vehicle registration laws.
Second, confirm the availability of the correct fuel (unleaded
and minimum octane rating).
TIPS FOR DRIVING IN VARIOUS CONDITIONS
Always slow down in gusty crosswinds. This will allow you
much better control.
 Drive slowly onto curbs and, if possible, at a right angle.
Avoid driving onto high, sharp-edged objects and other
road hazards. Failure to do so can lead to severe tire
damage such as a tire burst.
Drive slowly when passing over bumps or travelling on a
bumpy road. Otherwise, the impact could cause severe
damage to the tires and/or wheels.
 When parking on a hill, turn the front wheels until they touch
the curb so that the vehicle will not roll. Apply the parking
brake, and place the transmission in Pº. If necessary, block
the wheels.
 Washing your vehicle or driving through deep water may get
the brakes wet. To see whether they are wet, check that
there is no traffic near you and then press the pedal lightly.
If you do not feel a normal braking force, the brakes are
probably w et. To dry them, drive the vehicle cautiously while
lightly pressing the brake pedal with the parking brake
applied. If they still do not work safely, pull to the side of the
road and call a Lexus dealer for assistance.

DRIVING TIPS
434
CAUTION
Before driving off, make sure the parking brake is
fully released and that the parking brake reminder
light is off.
 Do not leave your vehicle unattended while the
engine is running.
 Do not rest your foot on the brake pedal while driving.
It can cause dangerous overheating, needless wear,
and poor fuel economy.
 To drive down a long or steep hill, reduce your speed
and downshift. Remember, if you ride the brakes
excessively, they may overheat and not work
properly. See page 381.
 Be careful when accelerating, upshifting,
downshifting or braking on a slippery surface. The
abrupt change in engine speed, such as sudden
acceleration or engine braking, could cause the
vehicle to spin or skid.
 Do not drive in excess of the speed limit. Even if the
legal speed limit permits it, do not drive over 140 km/h
(85 mph) unless your vehicle has high-speed
capability tires. Driving over 140 km/h (85 mph) may
result in tire failure, loss of control and possible
injury. Be sure to consult a tire dealer to determine
whether the tires on your vehicle are high-speed
capability tires or not before driving at such speeds.

DRIVING TIPS
435
Do not continue normal driving when the brakes are
wet. If they are wet, your vehicle will require a longer
stopping distance, and it may pull to one side when
the brakes are applied. Also, the parking brake will
not hold the vehicle securely.
 If you drive through deep water over about 500 mm
(20 in.) in depth, put the vehicle height in the HI (High)
mode with the active height select switch and then
turn off the active height control suspension by
pushing the height control switch. Drive your vehicle
at 30 km/h (19 mph) or lower speed.

DRIVING TIPS
436
OFF-ROAD DRIVINGPRECAUTIONS
When driving your vehicle off-road, please observe the
following precautions to ensure your driving enjoyment and to
help prevent the closure of areas to off-road vehicles.
a. Drive your vehicle only in areas where of f-road vehicles are
permitted to travel.
b. Respect private property. Get owner's permission before
entering private property.
c. Do not enter areas that are closed. Honor gates, barriers
and signs that restrict travel.
d. Stay on established roads. When conditions are wet,
driving techniques should be changed or travel delayed to
prevent damage to roads.
For owners in U.S. mainland, Hawaii and Puerto Rico:
To obtain additional information pertaining to driving your
vehicle off-road, consult the following organizations.
 State and Local Parks and Recreation Departments
 State Motor Vehicle Bureau
 Recreational Vehicle Clubs
 U.S. Forest Service and Bureau of Land Management
CAUTION
Always observe the following precautions to minimize
the risk of serious personal 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.
 In a rollover crash, an unbelted person is
significantly more likely to die than a person wearing
a seat belt. Therefore, the driver and all passengers
should fasten their seat belts whenever the vehicle is
moving.

DRIVING TIPS
438
NOTICE
If driving through water, such as when crossingshallow streams, first check the depth of the waterand the bottom of the river bed for firmness. Driveslowly and avoid deep water.
Take all necessary safety measures to ensure thatwater damage to the engine or other componentsdoes not occur.
Water entering the engine air intake will cause severe
engine damage.
Water can wash the grease from wheel bearings,causing rusting and premature failure, and may alsoenter the differentials, transmission and transfercase, reducing the gear oil's lubricating qualities.
Sand and mud that has accumulated in brake drumsand around brake discs may affect braking ef ficiency
and may damage brake system components.
Always perform a maintenance inspection after each day of off-road driving that has taken you throughrough terrain, sand, mud, or water. For scheduledmaintenance information, refer to the Owner'sManual Supplement/Scheduled Maintenanceº.

DRIVING TIPS
440Squirt
lock de-icer or glycerine into the locks to keep them from
freezing.
Use a washer fluid containing an antifreeze solution. This product is available at your Lexus dealer and most auto
parts stores. Follow the manufacturer's directions for how
much to mix with water.
NOTICE
Do not use engine antifreeze or any other substitute
because it may damage your vehicle's paint.
Do not use your parking brake when there is a possibility
it could freeze.
When parking, put the transmission into Pº and block the front
wheels. Do not use the parking brake, or snow or water
accumulated in and around the parking brake mechanism may
freeze the parking brake, making it hard to release. Keep ice and snow from accumulating under the fenders.
Ice and snow built up under your fenders can make steering
difficult. During bad winter driving, stop and check under the
fenders occasionally.
Depending on where you are driving, we recommend you
carry some emergency equipment.
Some of the thi
ngs you might put in the vehicle are tire chains,
window scraper, bag of sand or salt, flares, small shovel,
jumper cables, etc.

DRIVING TIPS
449
Matching trailer ball height to trailer coupler
height
No matter which class of tow hitch applies, for a safe trailer
hookup, the trailer ball setup on must be the proper height for
the coupler on the trailer.
32PY007

1Coupler2Trailer ball
Brakes and safety chains
Lexus recommends trailers with brakes that conform to
any applicable federal and state/provincial regulations.
 A safety chain must always be used between the towing
vehicle and the trailer. Leave sufficient slack in the
chain for turns. The chain should cross under the
trailer tongue to prevent the tongue from dropping to
the ground in case it becomes damaged or separated.
For correct safety chain procedures, consult your
Lexus dealer.
CAUTION
If the total trailer weight exceeds 453 kg (1000 lb.),
trailer brakes are required.
 Never tap into your vehicle's hydraulic system as it
will lower its 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 coupling unit or hitch ball,
there is possible danger of the trailer wandering over
into another lane.