2003 Lexus GX470 engine

STARTING AND DRIVING
322
 Slip indicator light
Leave the system on during the ordinary driving so that it
can operate when needed.
You may hear a 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 active traction control
system is in the self−check mode, but does not indicate a
malfunction.
When the active traction control system is operating, the
following conditions occur:
 The system controls the spinning of the 4 wheels. At this
time, the slip indicator light blinks.
 You may feel vibration or noise in your vehicle, caused by
operation of the brakes. This indicates the system is
functioning properly. The slip indicator light comes on for a few seconds when the
ignition key is turned to “ON”. If the indicator light does not
come on when the ignition is turned on, contact your Lexus
dealer.
“VSC TRAC” warning light
This light warns that there is a problem somewhere in the
following.

Active traction control system
 Vehicle skid control system
 Downhill assist control system
 Hill− start assist control system
When the system is normal and the ignition key is turned to
“ON”, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the “ON”
position.

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323
Depressing the brake pedal repeatedly may turn on the light.
It is normal if it goes out after a few seconds.
The brake actuator temperature increases during continuous
operation of
the above mentioned systems such as on slippery
roads. If the brake actuator temperature becomes too high
while any of the systems is operating, a buzzer will start to
sound intermittently to indicate that the active traction control
system can no longer operate. In this case, immediately stop
your vehicle at a safe place.
If the system continues to operate, the buzzer sound changes
from intermittent to continuous. (The continuous buzzer
sounds for about 3 seconds.) At the time, the “VSC TRAC”
warning light will come on and the active traction control
system temporarily stops operating in order to protect the
brake actuator. (Although the active traction control system
does not operate, there is no problem to continue your driving.)
The system will be automatically restored after a short time and
the “VSC TRAC” warning light goes out.
If the light comes on while driving, the active traction control
system does not work. However, as normal braking operates
when being applied, there is no problem to continue your
driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to “ON”.
 The warning light remains on after the ignition key is turned
to “ON”.
 The warning light comes on while driving.
VEHICLE SKID CONTROL SYSTEM
The vehicle skid control system helps provide integrated
control of the systems such as antilock brake system,
traction control, engine control, etc. This system
automatically controls t he output of the brakes or engine
to help prevent the vehicle from skidding when cornering
on a slippery road surface or operating steering wheel
abruptly.
The vehicle skid control activates when the vehicle speed is
more than following speed:
Four− wheel drive control lever in “H” 15 km/h (9 mph) . . .
Four−wheel drive control lever in “L” 30 km/h (19 mph) . . .
You may hear a 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 system is in the
self−check mode, but does not indicate a malfunction.
CAUTION
 Do not rely excessively on the vehicle skid control
system. Even if the vehicle skid control system is
operating, you must always drive carefully and
attentively to avoid serious injury. Reckless driving
will result in an unexpected accident. If the slip
indicator light blinks and an alarm sounds, special
care should be taken while driving.

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326
DOWNHILL ASSIST CONTROLSYSTEM
The downhill assist control system is a system that
assists the deceleration of the engine brake when you
drive down a steep hill. When you are driving down a hill
with the fourwheel drive control lever in the “L” position,
push the “DAC” switch to limit the vehicle’s acceleration.
If the vehicle is traveling at a speed of 25 km/h (15 mph) or
less, you can descend at a constant speed.
CAUTION
Do not rely excessively on the downhill assist control
system. It may not be able to maintain a low speed over
road surfaces or offroad surfaces on which sliding can
easily occur, such as extremely steep slopes or icy or
muddy roads.
Turning on the system
1. Shift the fourwheel drive control lever to the “L”
position.
The system will not operate if the four −wheel drive control lever
is in the “H” position.
2. In order to make full use of the engine brake, putting the
transmission in “L” or “2” is recommended.
The system will operate even if the transmission selector lever
is in “D”, “4”, “3” or “N”. However, when it is in “L” or “2” the
engine brake can also be utilized enabling the system to
operate more effectively.
3. Push the “DAC” switch to turn the system on. The
downhill assist control system indicator light on the
instrument panel will come on.
If the downhill assist control system indicator light flashes, the
transmission selector lever may be in “N” or four −wheel drive
control lever may be in the “H” position.

STARTING AND DRIVING
332You 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.
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 be longer.
Antilock brake system
The antilock brake system is designed to automatically
help prevent lockup of the wheels during a sudden brake
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.
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 the manhole cover, the steel plate under the construction,
joints in the 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 to the forward.

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335
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 48.
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 PAD WEAR LIMIT
INDICATORS
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.

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LIMITEDSLIP DIFFERENTIAL
Your Lexus is equipped with a limited−slip center differential
(transfer).
If one wheel − either front or rear − begins to spin, the transfer
(limited −slip center differential) is designed to aid traction by
automatically transmitting driving force to the wheels on the
other drive axle. It transmits driving force to the front wheels
if a rear wheel spins, and to the rear wheels if a front wheel
spins.
CAUTION
Do not start or run the engine while your vehicle is
supported by a jack. The vehicle could be driven off the
jack and could pose a danger or result in serious injury.
NOTICE
Use only a spare tire of the same size, construction and
load capacity as the original tires on your Lexus
because damage to the limitedslip differential could
possibly occur with another tire type.
TYPES OF TIRES
Determine what kind of tires your vehicle is originally equipped
with.
1. Summer tires
Summer tires are high −speed capability tires best suited to
highway driving under dry conditions.
Since summer tires do not have the same traction performance
as snow tires, summer tires are inadequate for driving on
snow−covered or icy roads. For driving on snow −covered or
icy roads, we recommend using snow tires. If installing snow
tires, be sure to replace all four tires.
2. All season tires
All season tires are designed to provide better traction in snow
and to be adequate for driving in most winter conditions, as well
as for use all year round.
All season tires, however, do not have adequate traction
performance compared with snow tires in heavy or loose snow.
Also, all season tires fall short in acceleration and handling
performance compared with summer tires in highway driving.

DRIVING TIPS
340
When driving offroad or in rugged terrain, do not
drive at excessive speeds, jump, make sharp turns,
strike objects, etc. This may cause loss of control or
vehicle rollover causing death or serious injury. You
are also risking expensive damage to your vehicle’s
suspension and chassis.
 Do not drive horizontally across steep slopes.
Driving straight up or straight down is preferred.
Your vehicle (or any similar offroad vehicle) can tip
over sideways much more easily than forward or
backward.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.
 Do not tow a trailer during the first 800 km (500 miles).

DRIVING TIPS
342
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 306.
 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 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.
 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.