steering Lexus GS430 2006 Scheduled Maintenance Guide / LEXUS 2006 GS430/GS300 FROM JAN. 2006 PROD. (OM30786U) Repair Manual

STARTING AND DRIVING
434Any 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.
 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.
CAUTION
Do not pump the brake pedal if the engine stalls.
Each push on the pedal uses up your reserved brake
fluid pressure.
 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.
Brake booster (GS300)
The brake booster uses engine vacuum to power −assist the
brakes. If the engine should quit 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 reserved
vacuum.
 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.
Antilock brake system
The antilock brake system is designed to automatically
help prevent lockup of the wheels during a sudden
braking or braking on slippery road surfaces. This assists
in providing directional stability and steering
performance of the vehicle under these circumstances.
Effective way to press the ABS brake pedal: When the
anti−lock brake system function is in action, you may feel the
brake pedal pulsating and hear a noise. In this situation, to
let the anti−lock brake system work for you, just hold the
brake pedal down more firmly. Do not pump the brake in a
panic stop. This will result in reduced braking performance.

STARTING AND DRIVING
435
The anti
−lock brake 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).
Depressing the brake pedal on slippery road surfaces such as
on a manhole cover, a steel plate at a construction site, joints
in a bridge, etc. on a rainy day tends to activate the anti −lock
brake system.
You may hear a click or motor sound in the engine
compartment for a few seconds when the engine is started or
just after the vehicle begins to move. This means that the
anti−lock brake system is in the self− check mode, and does not
indicate a malfunction.
When the antilock brake system is activated, the
following conditions may occur. They do not indicate a
malfunction of the system:
 You may hear the anti− lock brake system operating and feel
the brake pedal pulsating and the vibrations of the vehicle
body and steering wheel. You may also hear the motor
sound in the engine compartment even after the vehicle is
stopped.
 At the end of the anti−lock brake system activation, the
brake pedal may move a little forward.
CAUTION
Do not overestimate the antilock brake system:
Although the antilock brake system assists in
providing vehicle control, it is still important to drive
with all due care and maintain a moderate speed and
safe distance from the vehicle in front of you, because
there are limits to the vehicle stability and effectiveness
of steering wheel operation even with the antilock
brake system on.
If tire grip performance exceeds its capability, or if
hydroplaning occurs during high speed driving in the
rain, the antilock brake system does not provide
vehicle control.
Antilock brake system is not designed to shorten the
stopping distance: Always drive at a moderate speed
and maintain a safe distance from the vehicle in front of
you. Compared with vehicles without an antilock
brake system, your vehicle may require a longer
stopping distance in the following cases:
 Driving on rough, gravel or snowcovered roads.
 Driving with tire chains installed.
 Driving over the st eps such as the joints on the road.
 Driving on roads where the road surface is pitted or
has other differences in surface height.

STARTING AND DRIVING
438
BRAKE PAD WEAR LIMITINDICATORS
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.
ELECTRIC POWER STEERING SYSTEM
The electric power steering system, using an electric
motor, assists the turning of the steering wheel.
In the following cases, you may feel the steering becomes
heavy. However, the electric power steering system
warning light does not come on. (Because it is not a
malfunction.)
When maneuvering or turning frequently over a long time, the
power steering effect will be reduced to prevent the system
from overheating. A void turning the steering wheel, or stop the
vehicle. The system will become cool in about 10 minutes.
NOTICE
Frequent maneuvering and turning over a long time may
cause damage to the system in which the mechanism
prevents overheating of the electric power steering
system.
When the battery is discharged, check the battery’s condition.
If necessary, recharge or replace the battery. For details, see
“Checking battery condition” on page 581.

STARTING AND DRIVING
439
G31040
Electric power steering system warning light
The light comes on when the engine switch is selected in
“IG−ON” mode. If the electric power steering system works
properly, the light turns off after a few seconds. If the system
has malfunctions, the light comes on again.
If the following conditions occur, this indicates a
malfunction somewhere in the components monitored by
the warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.
 The light does not come on when the engine switch is
selected in “IG −ON” mode or remains on.
 The light stays on while you are driving.
CAUTION
If the electric power steering system warning light
comes on, take your vehicle to your Lexus dealer as
soon as possible. In this case, more effort is required
for the steering wheel to turn than usual. Drive your
vehicle while firmly gripping the steering wheel.

STARTING AND DRIVING
441
Display
Indicator
statusMeaningsDo this
Tire pressure
warning lightONTire inflation
pressure is
lowAdjust the tireinflation
pressure
Multi
information
displayLOW TIRE
(PRESSURE)
Tire pressure
warning lightBlinkingTire pressure
warning
system
malfunctionHave the
system
checked at
your Lexus
dealer
Multi
information
displayCHECK
(TIRE
PRES-
SURE)
SYSTEM
CAUTION
If the tire pressure warning light comes on, be sure to
observe the following precautions. Failure to do so
could cause loss of vehicle control and result in death
or serious injury.
Vehicles with runflat tires:
 Decelerate to the lowest appropriate speed as soon
as possible. Do not drive over 90 km/h (55 mph).
 Check and adjust the tire inflation pressure
immediately.
 If the tire pressure warning light comes on even after
tire inflation pressure adjustment, it is probable that
you have a flat tire. Have the tire replaced by the
nearest Lexus dealer.
 Avoid abrupt maneuvering and braking. If the vehicle
tires deteriorate, you could lose control of the
steering wheel or the brakes.
Vehicles with standard tires:
 Stop your vehicle in a safe place as soon as possible.
Adjust the tire inflation pressure immediately.
 If the tire pressure warning light comes on even after
tire inflation pressure adjustment, it is probable that
you have a flat tire. Check the tires. If the tire is flat,
change to the spare tire and have the flat tire repaired
by the nearest Lexus dealer.
 Avoid abrupt maneuvering and braking. If the vehicle
tires deteriorate, you could lose control of the
steering wheel or the brakes.

DRIVING TIPS
459
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 things you might put in the vehicle are tire chains,
window scraper, bag of sand or salt, flares, small shovel,
jumper cables, etc.
DINGHY TOWING
G32001
Your vehicle is not designed to be dinghy towed (with four
wheels on the ground) behind a motorhome.
NOTICE
Do not tow your vehicle with four wheels on the ground.
This may cause serious damage to your vehicle.

DRIVING TIPS
461

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.

DRIVING TIPS
462
VEHICLE LOAD LIMITS
Vehicle load limits include total load capacity, seating
capacity, towing capacity and cargo capacity . Follow the
load limits shown below. Total load capacity and seating
capacity are also described on the tire and loading
information label. For location of the tire and loading
information label, see “Checking tire inflation pressure”
on page 548.
Total load capacity: 370 kg (815 lb.)
Total load capacity means combined weight of
occupants, cargo and luggage.
Seating capacity: Total 5 (Front 2, Rear 3)
Seating capacity means the maximum number of
occupants whose estimated average weight is 68 kg
(150 lb.) per person. Depending on the weight of each
person, the seating capacity given may exceed the total
load capacity.
NOTICE
Even if the number of occupants are within the
seating capacity, do not exceed the total load
capacity.
Towing capacity
Lexus does not recommend towing a trailer with your
vehicle. Your vehicle is not designed for trailer towing.
Cargo capacity
Cargo capacity may increase or decrease depending on
the size (weight) and the number of occupants. For
details, see “Capacity and distribution” that follows.
CAUTION
Do not apply the load more than each load limit.
That may cause not only damage to the tires, but
also deterioration to the steering ability and
braking ability, which may cause an accident.

DRIVING TIPS
465
Example on Your Vehicle
32SA03
 1Cargo capacity 2Total load capacity
In case that 2 people with the combined weight of 166 kg
(366 lb.) are riding in your vehicle with the total load
capacity of 370 kg (815 lb.), the available amount of
cargo and luggage load capacity will be as follows:
370 kg – 166 kg = 204 kg.
(815 lb. – 366 lb. = 449 lb.)
From this condition, if 3 more passengers with the
combined weight of 176 kg (388 lb.) get on, the available
cargo and luggage load will be reduced as follows:
204 kg – 176 kg = 28 kg.
(449 lb. – 388 lb. = 61 lb.) As shown in the above example, if the number of
occupants increases, the cargo and luggage load
equaling the
combined weight of occupants who got on
later must be reduced. In other words, if the increase in
the number of occupants causes the excess of the total
load capacity (combined weight of occupants plus cargo
and luggage load), you have to reduce the cargo and
luggage on your vehicle.
For details about total load capacity, see “Vehicle load
limits” on page 462.CAUTION
Even if the total load of occupant’s weight and the
cargo load is less than the total load capacity, do
not apply the load unevenly. That may cause not
only damage to the tire but also deterioration to
the steering ability due to unbalance of the
vehicle, causing an accident.

IN CASE OF AN EMERGENCY
468
IF YOUR ENGINE STALLS WHILEDRIVING
If your engine stalls while driving . . .
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place.
2. Turn on your emergency flashers.
3. Turn the engine switch off, and try starting the engine again.
If the engine will not start, see ”If your vehicle will not start”\
.
CAUTION
If the engine is not running, the power assist for the
brakes and steering will not work, so steering and
braking will be much harder than usual.
IF YOUR VEHICLE WILL NOT START
(a) Simple checks
Before making these checks, make sure you have followed the
correct starting procedure instructions in ”Operating the
engine switch” on page 348 and that you have sufficient fuel.
Since your vehicle is equipped with the engine immobilizer,
also check whether the other keys will start the engine. If they
work, your electronic key may be broken. Have the key
checked at your Lexus dealer. If none of your keys work, there
may be a malfunction in the engine immobilizer. Call your
Lexus dealer. See ”Keys” on page 8.
If the engine is not turning over or is turning over too
slowly
1. Check that the battery terminals are tight and clean.
2. If the battery terminals are O.K., switch on the interior light.
3. If the light is out, dim or goes out when the starter is cranked,
the battery is discharged. You may try jump starting. See ”(c)
Jump starting” for further instruction.
4. If the engine does not start even after the battery has been
recharged or replaced, see “(d) Starting the engine after a
battery discharge” on page 472.
If the light is O.K., but the engine still will not start, it needs
adjustment or repair. Call a Lexus dealer, Roadside
Assistance or Customer Service Assistance. (See
”Foreword”.)