2006 Lexus GS430 brakes

STARTING AND DRIVING
420
Traction control system failure warning
G31039
 1GS430 2GS300
If the traction control system malfunctions, the slip
indicator light (twowheel drive models only) and brake
system warning light (yellow) come on. At this time, the
above message appears. (GS430 only—In some cases,
the multiinformation display shows either “CHECK VSC”
or “CHECK ECB” only.)
If the message appears, the traction control system, vehicle
stability control system and hill− start assist control system do
not work. Although it is no problem to continue driving, have
your vehicle checked by your Lexus dealer as soon as
possible.
VEHICLE STABILITY CONTROL SYSTEM
The vehicle stability control system helps provide
comprehensive control of the systems such as antilock
brake system, traction control, engine control, etc. This
system automatically controls the brakes and engine to
help prevent the vehicle from skidding when cornering on
a slippery road surface or operating steering wheel
abruptly.
This system activates when the vehicle speed is about more
than 15 km/h (9 mph).
You may hear a sound in the engine compartment for a few
seconds just after the vehicle begins to move. This means that
the system is in the self− check mode, but does not indicate a
malfunction.

STARTING AND DRIVING
427
BRAKE SYSTEM
This brake system has 2 independent hydraulic circuits. If
either circuit should fail, the other will still work. However, the
pedal will be harder to press, and your stopping distance will
increase. Also, the brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a single brake
system. Have your brakes fixed immediately.
Brake booster
The brake booster uses brake fluid pressurized by the pump
(GS430) or engine vacuum (GS300) to power −assist the
brakes. If the brake booster fails during driving, the brake
system warning light (red) comes on. In this case, the brakes
may not work properly. If they do not work well, depress the
brake pedal firmly. If the brake system warning light (red)
comes on, immediately stop your vehicle and contact your
Lexus dealer.
GS430 only—Either of the following conditions may
occur, but does not indicate a malfunction:
 The brake system warning light (red) may stay on for about
60 seconds after the engine is started. It is normal if the light
turns off after a while.
 Depressing the brake pedal repeatedly may turn on the
brake system warning light (red). It is normal if the light goes
out after a few seconds. GS430:
You may hear a small sound in the engine compartment after
the engine is started or the brake pedal is depressed
repeatedly. This is a pump pulsating sound of the brake
system, and it is not a malfunction.
GS300:
If the engine should stop while you are driving, you can bring
the vehicle to a stop with normal pedal pressure. There is
enough reserved vacuum for one or two stops—but no more!
CAUTION

Do not pump the brake pedal if the engine stalls.
Each push on the pedal uses up your brake fluid
pressure reserve.
 Even if the power assist is completely lost, the brakes
will still work. But you will have to push the pedal
hard, much harder than normal. And your braking
distance will increase.

STARTING AND DRIVING
431
Drumindisc 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.
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 light on page 78 or 430.
BRAKE PAD WEAR LIMIT
INDICATORS
G31006
The 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.
GS430 front brake only—
The high brake performance is achieved by proper wear of
brake pads and discs. As a result, the brake discs may wear
earlier than the ones on the conventional brake system.
When brake pads are replaced, brake disc thickness is
required to be measured.
It is dangerous to continue driving when brake pads and discs
have exceeded the wear limit.

STARTING AND DRIVING
435
CAUTION
If the low tire pressure warning light comes on, take
your vehicle to the nearest Lexus dealer or authorized
tire dealer or gas station as soon as possible, observing
the following instructions:
 Decelerate as soon as possible to the most
appropriate speed that conditions permit. Do not
drive over 90 km/h (55 mph).
 Avoid abrupt steering wheel maneuvering and
braking. If the vehicle tires deteriorate, you could
lose control of the steering wheel or the brakes,
causing death or serious injury.
 The warning system may not activate immediately if
bursts or sudden air leakage should occur.
When the tyre pressure warning system warning light is
lit, one or more of your tyres is significantly
underinflated. You should stop and check your tyres
as soon as possible, and inflate them to the proper
pressure as indicated on the vehicle’s tyre information
placard. Driving on a significantly underinflated tire
causes the tyre to overheat and can lead to tyre failure.
Underinflation also reduces fuel efficiency and tyre
tread life, and may affect the vehicle’s handling and
stopping ability. Each tyre, including the spare, should
be checked monthly when cold and set to the
recommended inflation pressure as specified in the
vehicle placard and owner’s manual.
NOTICE
 Do not use liquid sealants for a flat tire as tire
pressure sensors will be damaged.
 Take due care not to go over a curb stone and be
careful of the holes in the road because deflated tire
pressure affects tire cushion performance. The
wheels, tires, body, suspension and other
components could be damaged.
 Your ground clearance is reduced if the runflat tire
goes flat so avoid driving over obstacles and drive
slowly on rough, unpaved roads and speed bumps.
Also, do not attempt to go through an automatic car
wash as the vehicle may get caught, resulting in
damage.
 When the tires must be replaced, have them replaced
by the nearest Lexus dealer or authorized tire dealer.
The tire pressure sensor will be affected by the
installation or removal of tires.
 When the tires must be replaced, replace the
grommets for tire pressure sensors as well.

STARTING AND DRIVING
436Vehicles with standard tires:
Stop your vehicle at a safe place as soon as possible and
check that the tire inflation pressure
is as specified on the tire
and loading information label. If the low tire pressure warning
light comes on even after tire inflation pressure adjustment, it
is probable that you have a flat tire. If the tire goes flat, change
to the spare tire. (See page 469.)
The spare tire is not equipped with the tire pressure sensor.
So, the low tire pressure warning light remains on even if the
spare tire is mounted.
The light goes off a few minutes after air is put into the deflated
tire.
CAUTION
If the low tire pressure warning light comes on, observe
the following instructions:
 Decelerate as soon as possible to the most
appropriate speed that conditions permit.
 Avoid abrupt steering wheel maneuvering and
braking. If the vehicle tires deteriorate, you could
lose control of the steering wheel or the brakes,
causing death or serious injury.
 The warning system may not activate immediately if
bursts or sudden air leakage should occur.
When the tyre pressure warning system warning light is
lit, one or more of your tyres is significantly
underinflated. You should stop and check your tyres
as soon as possible, and inflate them to the proper
pressure as indicated on the vehicle’s tyre information
placard. Driving on a significantly underinflated tire
causes the tyre to overheat and can lead to tyre failure.
Underinflation also reduces fuel efficiency and tyre
tread life, and may affect the vehicle’s handling and
stopping ability. Each tyre, including the spare, should
be checked monthly when cold and set to the
recommended inflation pressure as specified in the
vehicle placard and owner’s manual.

DRIVING TIPS
450
BREAKIN PERIOD
Drive gently and avoid high speeds.
You need not follow a break−in schedule with your new Lexus.
But following a few simple tips for the first 1600 km (1000 miles)
can add to the future economy and long life of your vehicle:
 Avoid full throttle acceleration when starting and driving.
 Avoid racing the engine.
 Try to avoid hard stops during the first 300 km (200 miles).
 Do not drive for a long time at any single speed, either fast
or slow.
OPERATION IN FOREIGN
COUNTRIES
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 ”P”. 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 wet. To dry them, drive the vehicle cautiously while
lightly pressing the brake pedal with the parking brake
applied. If they still do not work safel y, pull to the side of the
road and call a Lexus dealer for assistance.

DRIVING TIPS
451
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 359.
 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 skid or spin.
 Even if the legal speed limit permits it, do not drive
over 140 km/h (85 mph) unless your vehicle has
highspeed 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
highspeed capability tires or not before driving at
such speeds.
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.

DRIVING TIPS
455

Avoid continuous speeding up and slowing down.
Stop−and−go driving wastes fuel.
 Avoid unnecessary stopping and braking. Maintain a
steady pace. Try to time the traf fic signals so you only need
to stop as little as possible or take advantage of through
streets to avoid traffic lights. Keep a proper distance from
other vehicles to avoid sudden braking. This will also
reduce wear on your brakes.
 Avoid heavy traffic or traffic jams whenever possible.
 Do not rest your foot on the brake pedal. This causes
premature wear, overheating and poor fuel economy.
 Maintain a moderate speed on highways. The faster you
drive, the greater the fuel consumption. By reducing your
speed, you will cut down on fuel consumption.
 Keep the front wheels in proper alignment. Avoid hitting
the curb and slow down on rough roads. Improper
alignment not only causes faster tire wear but also puts an
extra load on the engine, which, in turn, wastes fuel.
 Keep the bottom of your vehicle free from mud, etc.
This not only lessens weight but also helps prevent
corrosion. 
Keep your vehicle tunedup and in top shape. A dirty air
cleaner, improper valve clearance, dirty plugs, dirty oil and
grease, brakes not adjusted, etc. all lower engine
performance and contribute to poor fuel economy. For
longer life of all parts and lower operating costs, keep all
maintenance work on schedule, and if you often drive under
severe conditions, see that your vehicle receives more
frequent maintenance (For scheduled maintenance
information, please refer to the “Owner’s Manual
Supplement / Scheduled Maintenance”.)
CAUTION
Never turn off the engine to coast down hills. Your
power steering and brake booster will not function
without the engine running. Also, the emission control
system operates properly only when the engine is
running.