brakes Lexus GS300 2006 Starting and Driving

STARTING AND DRIVING
368
Indicators and steering guide symbol
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1
Detection by dual sensors
2
Detection by rear corner sensors
3
Detection by back sensors
4
Steering guide symbol (See page 371)
The approximate distance to the obstacle is shown with up to
4 bars on the front, front corners and rear of the vehicle and up
to 3 bars on the rear corners of the vehicle.
CAUTION
To avoid an accident or injury, observe the following
instructions, and then drive slowly using the brakes
while confirming a safe distance around your vehicle
with your eyes.
The sensor detection range is limited around the
bumper. Be sure to confirm safety outside sensor
detection with your eyes. For the sensor detection
range, see page 376.
It might take time for the sensors to detect the
obstacle.
Depending on the shape of the obstacle, indicators or
beeps may not warn you properly, and the detection
range may also be shortened.
It might be difficult to hear beeps due to the volume
of audio or air flow noise of air conditioning.

STARTING AND DRIVING
376The warning for the obstacle closer to the vehicle will be
issued. The above illustration indicates the obstacle detected
by the back sensors is closer to the vehicle. So, the warning for
the obstacle detected by the back sensors will be given.
2
The obstacle detected on the front or rear of the
vehicle is in an area where continuous beeping
should sound:
If the possibility of collision with the obstacle is high as shown,
the system warns the driver by continuous beeping (repeating
6 intermittent beeps and one longer beep as one cycle).
3
Both obstacles detected on the front and rear of the
vehicle are in areas where continuous beeping
should sound:
If the possibility of collision with the obstacles is very high as
shown, the system warns the driver by continuous beeping
(repeating 2 quick beeps and one longer beep as one cycle).
CAUTION
It might be difficult to hear beeps due to the volume of
audio or air flow noise of air conditioning. To avoid an
accident or injury, drive slowly using the brakes while
confirming a safe distance around your vehicle with
your eyes.
Detection range of sensors*
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1
About 3 m (10 ft.) 2
About 1 m (3 ft.)
3
About 1m 50 cm (5 ft.) 4
About 50 cm (1.5 ft.)
The sensor detection range is limited around the bumper.
Be sure to confirm a safe distance around your vehicle
and drive slowly.

STARTING AND DRIVING
397 (a) Dynamic radar cruise control operations
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The dynamic radar cruise control function operates
automatically and depending on whether a vehicle is
detected ahead may change the speed of your vehicle as
follows:If no vehicle is running ahead of you:
1
Cruising at a fixed speed: If there is no vehicle detected
ahead, your cruising speed is maintained at the preset
speed from about 45 km/h (28 mph) to about 135 km/h (85
mph). The preset speed is displayed in the
multi−information display. For the vehicle speed setting,
see “Setting operation ” on page 402.
If a vehicle is detected ahead of you:
2
Deceleration cruising function: If a slower moving
vehicle is detected ahead of you, your vehicle cruising
speed decreases within the range of about 40 km/h (25
mph) to about 135 km/h (85 mph). The multi−information
display shows the preset speed, the detected vehicle
ahead and selected vehicle−to−vehicle distance. If your
vehicle gets closer to the vehicle ahead because of
insufficient automatic deceleration, then the warning tone
warns you to also manually apply brakes.
3
Follow−up cruising function: After deceleration, your
vehicle cruising speed changes in proportion to the speed
of the vehicle ahead to maintain an appropriate distance
from your vehicle to the vehicle ahead. The
vehicle−to−vehicle distance can be changed. For details,
see “Changing vehicle−to−vehicle distance setting” on
page 406.
4
Acceleration cruising function: If the vehicle ahead
changes lanes, your vehicle cruising speed will be
gradually increased up to the preset speed, and your
vehicle resumes fixed−speed cruising.

STARTING AND DRIVING
398
CAUTION
Under certain conditions where the vehicle in front
slows drastically, or is stopped, the dynamic radar
cruise control will neither warn you nor decelerate. The
driver must depress the brake pedal to slow down,
ensuring collision avoidance or that sufficient
vehicle−to−vehicle distance is maintained.
When vehicle−to−vehicle distance control mode is activated,
you must still be attentive to road and traffic conditions. Should
your vehicle speed decrease below about 40 km/h (25 mph),
the dynamic radar cruise control will shut off, requiring you to
apply the brakes to slow. When a vehicle ahead slows
suddenly, stops or a vehicle cuts in front, the system may slow
your vehicle abruptly, but the automatic braking will cease if the
speed decreases below about 40 km/h (25 mph) requiring the
driver’s manual application of brakes.
CAUTION
Certain conditions make vehicle detection difficult or
impossible.
As this system operates by detecting primarily the
reflected wave from the rear end of the vehicle ahead,
the distance cannot be accurately detected in the
following cases, resulting in improper
vehicle−to−vehicle distance.
♦The rear section of the vehicle ahead is extremely
small such as an unloaded trailer.
♦The vehicle ahead or other vehicles around you
are flinging up water or snow.
♦Heavy luggage which is loaded in your trunk or on
top of your rear seats is raising up the nose of your
vehicle.
The millimeter wave radar sensor automatically
detects dirt if it is sticking to the front of the sensor
or cover of your vehicle, and if detected, a message
appears on the multi−information display. However,
if the sensor or cover is covered with a metallic vinyl
bag, icicle, snowflakes, etc., dirt may not be detected,
resulting in improper vehicle−to−vehicle distance.
Continue driving with due care to the vehicle ahead.
If dirt is detected, the dynamic radar cruise control
function is automatically cancelled. Always keep the
sensor and cover clean.

STARTING AND DRIVING
403
2
Cancelling the preset speed
You can cancel the preset speed by doing any of the following:
a. Pulling the control lever, in the ”CANCEL” direction.
b. Depressing the brake pedal.
c. Pushing the “ON−OFF” button.
If cancelled by a. or b., the multi−information display shows
“RADAR READY” and the dynamic radar cruise control enters
the ready mode.
If cancelled by c., the “CRUISE” indicator light goes off in the
instrument cluster and the multi−information display shows
“CRUISE OFF”. In this case, the preset speed data is cleared,
and you must set the speed from the beginning.
In the following case, the preset speed automatically
cancels out. At this time, the multi−information display
shows “RADAR READY” and the dynamic radar cruise
control enters the ready mode.
The vehicle speed falls below about 40 km/h (25 mph). (40
km/h (25 mph) is designated as a cancel speed.)
CAUTION
In this case, the warning tone reminds you that the
dynamic radar cruise control is cancelled and you must
apply the brakes to slow the vehicle.
In the following cases, the warning messages appear and
the preset speed automatically cancels out. When
dynamic radar cruise control is restored, the warning
messages turn off and dynamic radar cruise control
enters “RADAR READY” mode.
a. The slip indicator light blinks and a warning tone sounds.
(This occurs when the vehicle is about to skid.)
b. The driving pattern selector switch is set to snow mode.
c. The anti−lock brake system is activated by automatic
braking. (The warning tone sounds.)
d. The sensor does not operate properly because a foreign
matter sticks to the sensor.
e. The wipers are operated at high speed (including high
speed operation with the wiper lever in the “AUTO” position.)
NOTICE
If the preset speed automatically cancels out for other
than the above reasons, do not operate the dynamic
radar cruise control. Although it is no problem to
continue driving, have your vehicle checked by your
Lexus dealer at the earliest opportunity.

STARTING AND DRIVING
407 (e) Braking control
Dynamic radar cruise control is not a collision avoidance
system. If an approach warning is activated, depress the brake
pedal to decelerate to ensure an appropriate
vehicle−to−vehicle distance.
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1
Under the vehicle−to−vehicle distance control
2
Braking activated
Braking control is operating only when the vehicle−to−vehicle
distance control mode is selected and your vehicle speed
exceeds about 40 km/h (25 mph).
If you are getting closer to the vehicle ahead at relatively higher
speed than those of the vehicle ahead or if engine braking
cannot be applied properly, braking control is automatically
activated. At this time, “BRAKE” flashes on the
multi−information display, indicating that the brakes are being
used.
CAUTION
Braking control will not ensure that your vehicle will
reduce speed appropriately. Do not rely on dynamic
radar cruise control to prevent collision.

STARTING AND DRIVING
418
TRACTION CONTROL SYSTEM
The traction control system automatically helps prevent
the spinning of rear wheels when the vehicle is started or
accelerated on slippery road surfaces.
When the engine switch is selected in “IG−ON” mode, the
system automatically turns on.
CAUTION
Under certain slippery road conditions, full traction of
the vehicle and power against rear 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.
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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 just after the vehicle begins to move. This means that
the traction control system is in the self−check mode, but does
not indicate a malfunction.
When the traction control system is operating, the following
conditions occur:
The system controls the spinning of the rear 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.
GS430—The slip indicator light comes on when the engine
switch is selected in “IG−ON” mode. The light goes off when
the engine is started.

STARTING AND DRIVING
420
Traction control system failure warning
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1
GS430 2
GS300
If the traction control system malfunctions, the slip
indicator light (two−wheel drive models only) and brake
system warning light (yellow) come on. At this time, the
above message appears. (GS430 only—In some cases,
the multi−information 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 anti−lock
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
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.
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.