warning Lexus GX470 2004 Engine / LEXUS 2004 GX470 FROM AUG. 2004 THROUGH SEP. 2004 PROD. (OM60B55U) Service Manual

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424
The indicator light comes on when the system is on while
driving.
NOTICE
Make sure that the center differential lock indicator light
goes off before normal driving.
VSC TRACº warning light
This li ght warns that when there is a problem somewhere in the
following. 
Vehicle stability control system
 Active traction control system
 Downhill assist control system
 Hill-start assist control system
When the system is normal and the ignition key is turned to
ONº, 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 ONº
position.
Depressing the brake pedal repeatedly may turn on the light.
It is normal if they go out after a few seconds.
If the light comes on while driving, the vehicle stability 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 ONº.
 The warning light remains on after the ignition key is turned
to ONº.

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The warning light comes on while driving.
DOWNHILL ASSIST CONTROL
SYSTEM
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 four-wheel drive control lever in the Lº position,
push the DACº 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 off-road surfaces on which sliding can
easily occur, such as extremely steep slopes or icy or
muddy roads.
Turning on the system
1. Shift the four-wheel drive control lever to the Lº
position.
The system will not operate if the four-wheel drive control lever
is in the Hº position.
2. In order to make full use of the engine brake, putting the
transmission in Lº or 2º is recommended.
The system will operate even if the transmission selector lever
is in Dº, 4º, 3º or Nº. However, when it is in Lº or 2º the
engine brake can also be utilized enabling the system to
operate more effectively.
3. Push the DACº switch to turn the system on. The
downhill assist control system indicator light on the
instrument panel will come on.

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VSC TRACº warning light
If there is any abnormality in the system, the VSC TRACº
warning light will come on. When the DACº switch is
pushed, the downhill assist control system indicator light
also flash.
If the VSC TRACº warning light comes on, there may be an
abnormality in any of the following systems in addition to the
downhill assist control system.
Hill-start assist control system
 Active traction control system
 Vehicle stability control system
When the system is normal and the ignition key is turned to
ONº, 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 ONº
position. 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 system on such as 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 downhill assist control
system can no longer operate. In this case, stop your vehicle
immediately 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 this time, the VSC TRACº
warning light will come on and the downhill assist control
system stops operating temporarily in order to protect the
brake actuator. (Although the downhill assist control system
does
not operate, it is no problem to continue your driving.) The
system w ill be automatically restored after a short time and the
VSC TRACº warning light goes out.
If the warning light comes on while driving, the system does not
work. However, as normal braking operates when being
applied, it 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 ONº.
 The warning light remains on after the ignition key is turned
to ONº.
 The warning light comes on while driving.

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429
The slip indicator light comes on for a few seconds when the
ignition key is turned to ONº. If the indicator light does not
come on when the ignition is turned on, contact your Lexus
dealer.
Keep in mind the following when driving.

The hill-start assist control system operates for 5 seconds
maximally. If both the brake and accelerator pedals remain
undepressed for longer than 5 seconds, the buzzer will
sound at more frequent intervals and the system will
gradually stop operating.
 The hill-start assist control system is not designed as a
function for stopping the vehicle on a uphill slope. When
stopping the vehicle, be sure to depress the brake pedal.
If the system is used frequently, the brake actuator
temperature may become too high and a buzzer will sound
intermittently.
In this case, a buzzer will sound intermittently. When the
temperature of the brake actuator goes down, the system will
begin to operate again. Until it restarts, the active traction
control system and downhill assist control system will not
operate; however, the conventional brake can be operated.
VSC TRACº warning light
If there is any abnormality in the system, the VSC TRACº
warning light will come on.
If the system malfunctions, the VSC TRACº warning light will
come on.
If the VSC TRACº warning light comes on, there may be an
abnormality in any of the following systems in addition to the
hill-start assist control system.
 Downhill assist control system
 Active traction control system
 Vehicle stability control system
When the system is normal and the ignition key is turned to
ONº, 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 ONº
position.

STARTING AND DRIVING
430Depressing 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 system on such as 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 hill-start assist control
system can no longer operate. In this case, stop your vehicle
immediately 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 this time, the VSC TRACº
warning light will come on and the hill-start assist control
system stops operating temporarily in order to protect the
brake actuator. (Although the hill-start assist control system
does
not operate, it is no problem to continue your driving.) The
system w ill be automatically restored after a short time and the
VSC TRACº warning light goes out.
If the warning light comes on while driving, the system does not
work. However, as normal braking operates when being
applied, it 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 ONº.
 The warning light remains on after the ignition key is turned
to ONº.
 The warning light comes on while driving.
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
to power-assist the brakes. If the brake booster fails during
driving, the brake system warning light comes on and buzzer
sounds continuously. 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 comes on, immediately
stop your vehicle and contact your Lexus dealer.
The brake system warning light may stay on for about 60
seconds after the ignition key is turned to the ONº position. It
is normal if the light turns off after a while.
Depressing the brake pedal repeatedly may turn on the brake
system warning light and buzzer. It is normal if the light goes
out and the buzzer stops sounding after a few seconds.

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ABSº warning light

1U.S.A.2Canada
The light comes on when the ignition key is turned to the ONº
position. If the anti-lock brake system and the brake assist
system work properly, the light turns off after a few seconds.
Thereafter, if either of the systems malfunctions, the light
comes on again.
When the ABSº warning light is on (and the brake system
warning light is off), the anti-lock brake system, the brake
assist system, the active traction control system and the
vehicle stability control system do/does not operate, but the
brake system still operates conventionally.
When the ABSº warning light is on (and the brake system
warning light is off), the anti-lock brake system does not
operate so that the wheels could lock up during a sudden
braking or braking on slippery road surfaces.
If either of the following conditions occurs, 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 ignition key is turned
to the ONº position, or remains on.
 The light comes on while you are driving.
A warning light turning on briefly during operation does not
indicate a problem.
CAUTION
If the ABSº warning light remains on together with the
brake system warning light, immediately stop your
vehicle at a safe place and contact your Lexus dealer.
In this case, not only the anti-lock brake system will fail
but also the vehicle will become extremely unstable
during braking.
Either of the following conditions may occur, but do not
indicate a malfunction:
 The light may stay on for about 60 seconds after the ignition
key is turned to the ONº position. It is normal if it turns off
after a while.
 Depressing the brake pedal repeatedly may turn on the
light. It is normal if it turns off after a few seconds.

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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 67.
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.

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If 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 579.) 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 487.
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.

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NOTICE
Do not use liquid sealants for a flat tire as air pressuresensors will be damaged.
When the tires must be repaired or replaced, havethem repaired or replaced by the nearest Lexusdealer or authorized tire dealer. The tire pressuresensors will be affected by the installation or removal
of tires.
The tire pressure warning system is not to be used as a substitute for regular inspections. Be sure to check
the air pressure in the tires on a regular basis.
When the tires must be replaced, replace the grommets for air pressure sensors as well.
If the warning light blinks:
The tire pressure warning system may be malfunctioning.
Contact your Lexus dealer.System malfunction
The tire pressure warning system does not function
properly under certain circumstances. In the following
cases, the low tire pressure warning light may not come
on even if the tire inflation pressure is low, or it may come
on when the tire inflation pressure is actually normal.
 Electric devices or facilities using similar radio wave
frequencies are nearby.
 A radio set to similar frequencies is in use.
 A lot of snow or ice covers the vehicle, in particular, around
the wheels or wheel housings.
 The tires are not equipped with an air pressure sensor.
 Tire chains are used.

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CAUTION
When the tire pressure monitoring system warning light
is lit, one or more of your tires is significantly
under-inflated. You should stop and check your tires as
soon as possible, and inflate them to the proper
pressure as indicated on the vehicle's tire information
placard. Driving on a significantly under-inflated tire
causes the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle's handling and
stopping ability. Each tire, 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.
For vehicles sold in U.S.A.