2003 Lexus GX470 4 wheel drive

STARTING AND DRIVING
309
(g) If you cannot shift the selector lever
If you cannot shift the selector lever even though the brake
pedal is depressed, use the shift lock override button. For
instructions, see “If you cannot shift automatic transmission
selector lever” on page 382.
(h) Driving in second start mode
In the second start mode, the transmission system shifts up
from second gear. Use this mode when starting your vehicle
in sand, mud, ice or snow.
To set the second start mode, push the “2nd STRT” switch. In
the second start mode, the “2nd STRT” indicator light comes
on. To cancel the second start mode, push the “2nd STRT”
switch once again.
FOURWHEEL DRIVE SYSTEM
(a) Fourwheel drive control
Use the fourwheel drive control lever and center
differential lock button to select the following transfer and
center differential modes.
The “H” and “L” position of the four −wheel drive control lever
provides either lock or unlock mode of the center differential
depending on the center differential lock button position.
Use the center dif ferential lock system if your wheels get stuck
in a ditch, or when you are driving on a slippery or bumpy
surface. When the center dif ferential is locked, the vehicle skid
control system is automatically turned off and the center
differential lock and “VSC OFF” indicator lights come on
because the function that controls engine performance
interferes with the process of freeing your wheels.

STARTING AND DRIVING
310
NOTICE
As soon as the center differential lock switch is turned
on, the “VSC OFF” indicator light comes on. After the
wheels are out of the ditch or off the slippery or bumpy
surface, turn the center differential lock switch off.
Make sure the center differential lock indicator light and
vehicle skid control system off indicator light turn off.
“H” (high speed position, center differential unlocked):
Lever at “H”, center differential lock button left out
Use this for normal driving on all types of roads, from dry
hard−surfaced roads to wet, icy or snow −covered roads. This
position gives greater economy, quietest ride, least wear and
better vehicle control.
“H” (high speed position, center differential locked):
Lever at “H”, center differential lock button pushed in
Use this for greater traction when you experience a loss of
power, such as wheel slipping, in the center dif ferential unlock
mode.
“N” (neutral position): Lever at “N”
No power is delivered to the wheels. The vehicle must be
stopped. “L” (low speed position, center differential unlocked):
Lever at “L”, center differential lock button left out
Use this for maximum power and traction. Use this for climbing
or descending steep hills, off
−road driving, and hard pulling in
sand or mud.
In this mode, the braking feeling that occurs when the wheels
are negotiating a sharp corner is further reduced than in the “L”
(low position, center differential locked) mode.
“L” (low speed position, center differential locked): Lever
at “L”, center differential lock button pushed in
Use this for maximum power and traction. Use this for hard
pulling in situations the vehicle cannot negotiate even in the “L”
(low speed position, center differential unlocked) mode. Also,
using this mode when driving down steep off −road inclines will
help contribute to increased vehicle stability.
The indicator light tells when the differential lock is engaged.
Note that the differential is not still locked as long as the
indicator light remains off.
When the operation is not completed, the indicator blinks. If the
indicator light does not go off when you push out the center
differential lock switch, drive straight ahead while accelerating
or decelerating, or drive in reverse.
The center differential lock system operation is not completed
within 5 seconds while the cruise control system is set, cancel
the cruise control system. To cancel the cruise control system,
see “Cruise control” on page 312.
If the indicator light does not go off when you push out the
center differential lock button, drive straight ahead while
accelerating or decelerating, or drive in reverse.

STARTING AND DRIVING
311
See “(b) Shifting procedure” for further instructions.
Advice for driving on slippery roads in “L” (low speed
position) mode
If you shift the four−wheel drive control lever to “L”, the
automatic transmission lever to “2” when you drive in steep
off−road areas, the output of the brake can be controlled
effectively by the active traction control system, which assists
the driver to control the driving power of 4 wheels.
Use the “L” position of the automatic transmission lever for
maximum power and traction when your wheels get stuck or
when you drive down a steep incline. In the following cases,
the out put of the brake can be controlled by the active traction
control system if the engine speed is under 3,000 rpm
(normally engine speed is under 3,000 rpm when the wheels
get unstuck).
 The four− wheel drive control lever in the “L” position and the
automatic transmission lever in the “L” position or the
automatic transmission lever in the “D” or “2” with the
transmission downshifting to the first gear.
 The four− wheel drive control lever in the “L” position and the
automatic transmission lever in the “R” position
(As for the automatic transmission lever positions, see
“Automatic transmission” on page 303.)
(b) Shifting procedure
To shift between unlock and lock modes in “H”, push the
center differential lock button.
To shift between unlock and lock modes in “L”, push the
center differential lock button.
To shift between “H” and “L”, stop the vehicle, put the
transmission into “N” and move the four −wheel drive control
lever.
CAUTION
Never move the fourwheel drive control lever if wheels
are slipping. Stop the slipping or spinning before
shifting.
NOTICE
For normal driving on dry and hard surface roads,
unlock the center differential. To prevent damage to the
center differential lock system, do not push the center
differential lock button when the vehicle is cornering or
when its wheels are spinning freely of f the ground. If the
indicator light does not go off when unlocking the
center differential, drive straight ahead while
accelerating or decelerating, or drive in reverse.

STARTING AND DRIVING
321
When your vehicle is loaded heavily or you are driving in an
unpaved road, the mode

3
or 4
will be recommended. To
provide good vehicle stability, the damping effect will be harder
than for ordinary driving mode.
With the four−wheel drive control lever at “L”, the damping
effect suitable for off −road driving will be harder in any mode.ACTIVE TRACTION CONTROL
SYSTEM
The active traction control system automatically helps
prevent the spinning of 4 wheels when the vehicle is
started or accelerated on slippery road surfaces.
When the ignition key is turned to “ON”, the system
automatically turns on.
CAUTION
Under certain slippery road conditions, full traction of
the vehicle and power to the 4 wheels cannot be
maintained, even though the traction control system is
in operation. Do not drive the vehicle under any speed
or maneuvering conditions which may cause the
vehicle to lose traction control. In situations where the
road surface is covered with ice or snow, your vehicle
should be fitted with snow tires or tire chains. Always
drive at an appropriate and cautious speed for the
present road conditions.

STARTING AND DRIVING
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.

STARTING AND DRIVING
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
333
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 tires 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 the 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 steps such as the joints on the road.
 Driving on roads where the road surface is pitted or
has other differences in surface height.
Install all 4 tires of specified size at appropriate
pressure: The antilock brake system detects vehicle
speeds using the speed sensors for respective wheels’
turning speeds. The use of tires other than specified
may fail to detect the accurate turning speed resulting
in a longer stopping distance.

STARTING AND DRIVING
336
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.