brake Lexus GS450h 2007 Using the hands-free system (for cellular phone) / LEXUS 2007 GS450H THROUGH JUNE 2006 PROD. (OM30727U) Owner's Guide

133
2-4. Using other driving systems
2
When driving
Cruising in vehicle-to-vehicle distance control mode
This mode employs a radar sensor to detect the presence of vehicles
within 400 ft. (120 m) ahead and to judge the distance between your
vehicle and those vehicles.
Note that vehicle-to-vehicle distance will close when traveling on long down -
hill slopes.
Example of constant speed cruising (when there are no vehicles
ahead): When set to 62 mph (100 km/h)
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehi-
cle distance can also be set by operating the vehicle-to-vehicle distance
swi
tch.
Example of deceleration cruising (wh en the vehicle ahead is driving
slower than the set speed): When fixed speed cruising is set at 6
2 mph
(100 km/h) and the vehicle ahead is driving at 50 mph (80 km/h)
When a vehicle is detected running ahead of you, in the same lane, the sys -
tem automatically decelerates your vehicle. When a greater reduction in
v
ehicle speed is necessary, the system applies the brakes. A warning tone
warns you on the system cannot decelerate sufficiently to prevent your vehi -
cle from closing on the vehicle ahead.

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2-4. Using other driving systems
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When driving
CAUTION
■Before using dynamic radar cruise control
Do not overly rely on vehicle-to-vehicle distance control.
Be aware of the set vehicle speed. If au tomatic deceleration/acceleration is not
appropriate, adjust the vehicle speed, as well as the distance between your vehicle
and vehicles ahead by applying the brakes, etc.
■To avoid operating the dynamic radar cruise control by mistake
Keep the “ON-OFF” button off when not in use.
■Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise contro l in any of the following situations.
Doing so may result in inappropriate cont rol of speed and could cause serious or
fatal accident.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as thos e covered with rain, ice or snow
●Where there are sudden changes between sharp up and down gradients
●At entrances to expressways
●When weather conditions are bad enough that they may prevent the sensors
from functioning correctly (f og, snow, sandstorm, etc.)
●Where buzzer can be heard often

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2-4. Using other driving systems
CAUTION
■When the radar sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are in
front of you.
As the sensor may not be able to correctly detect these types of vehicles, the prox-
imity alarm ( P. 447) will not be activated, and an accident may result.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving
●Vehicles with small rear ends (tra ilers with no load on board etc.)
●Motorcycles traveling in the same lane
■Conditions under which the vehicle-to-vehicle distance control may not function
correctly
Apply the brakes as necessary in the foll owing conditions as the radar sensor may
not be able to correctly detect vehicles ahead, and an accident may result.
●When water or snow thrown up by the surrounding vehicles hinders the function-
ing of the sensor
●When your vehicle is pointing upwards (caused by a heavy load in the trunk, etc.)
●When the road curves or when the lanes are narrow
●When steering wheel operation or your position in the lane is unstable
■To ensure the radar sensor functions correctly
Do not do the following to the sensor or grille cover as doing so may cause the sen-
sor not to function correctly and could result in an accident.
●Stick or attach anything to them
●Leave them dirty
●Disassemble, subject them to strong shocks
●Modify or paint them
●Replace them with non-genuine parts

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2-4. Using other driving systems
■When the system malfunctions
●If a malfunction occurs and no obstacles have been detected, a warning is dis-
played, and a malfunction beep sounds for 7 seconds. 
If an obstacle has been detected, or another malfunction occurs in a different
sensor
, the malfunction beeps will not sound.
●In the following circumstances the displayed warning will disappear:
• If you switch the screen to a different mode.
• If you turn OFF the intuitive parking assist main switch.
• If the vehicle speed exceeds 6 mph (10 km/h). Once the vehicle speed drops
b
elow 6 mph (10 km/h), the warning will be displayed again.
●If the malfunction screen is displayed, the detection range of the dual sensors is
shortened. In this case, the necessity fo r obstacle evasion (whether the obstacle
will come within 0.8 ft. (25 cm) of the vehicle or not) will not be calculated.
■When using intuitive parking assist
●The sensors' detection areas and reaction times are limited. When moving for -
ward or reversing, check the areas surrounding the vehicle (especially the sides
of the
vehicle) for safety, and drive slowly, using the brake to control the vehicle’s
speed.
• The sensors' detection areas are limited to the ar
eas around the vehicle’s front
and rear bumpers.
• Depending on the shape of the obstacle
and other factors, the detection dis-
tance may shorten, or dete ction may be impos
sible.
• There will be a short delay between ob stacl
e detection and display. Even at
slow speeds, there is a possibility that the obstacle will come within 0.8 ft. (25
cm) of the vehicle before the display is shown and the warning beep sounds.
• Braking distance may differ according to the road conditions (rain, gravel
et
c.).
• It might be difficult to hear beeps due to the volume of audio system or air fl
ow noise of air conditioning system.
• For long obstacles such as walls, the obstacle warning may change as the o
bstacle gets closer.

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2-4. Using other driving systems
Driving assist systems
To help enhance driving safety and performance, the following systems
operate automatically in response to various driving situations. Be aware,
however, that these systems are supplementary and should not be relied
upon too heavily when operating the vehicle.
■ABS (Anti-lock Brake System)
Restrains the vehicle from slipping when driving on slick road surfaces or
in the event of sudden braking.
■BA (Brake Assist)
Generates an increased level of braking force after the brake pedal is
depressed, when the system detects a panic stop situation.
■VSC (Vehicle Stability Control)
Helps the driver to control skidding wh en swerving suddenly or turning on
slippery road surfaces.
■ TRAC (Traction Control)
Maintains drive power and prevents the rear wheels from spinning when
starting the vehicle or accelerating on slippery roads.
■Hill-start assist control
Helps prevent the vehicle from rolling backwards when starting on an
incline or slippery slope. It operat es for approximately 5 seconds at maxi -
mum.
■ VGRS (Variable Gear Ratio Steering)
Adjusts the wheel turning angle in accordance with the vehicle speed and
steering wheel movement.
■EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.
■Active stabilizer suspension system
Turns at smaller angles to main tain the stable vehicle posture.

163
2-4. Using other driving systems
2
When driving
When the VSC/TRAC/hill-start assist control systems are operating
If the vehicle is in danger of slip-
ping, rolling backwards when
star
ting on an incli ne, or if the rear
wheels spin, the slip indicator light
flashes to indicate that the VSC/
TRAC/hill-start assist control sys -
tems have been engaged.
A buzzer (intermittent) sounds to
indicate that VSC is operating.
The stop lights and high mounted
stoplight turn on when the hill-star
t
assist control system is operating.
The slip indicator light flashes as
well when ABS is operating.
■ VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the AB S, VSC, TRAC, hill-start assist con-
trol, VGRS and EPS systems. 
Maintains vehicle stability when swerving on slippery road surfaces by
contr
olling the brakes, engine output, and the movement of the front
wheels.
■ PCS (Pre-Collision System) (if equipped)
 P. 1 6 7

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2-4. Using other driving systems
To disable TRAC
If the vehicle gets stuck in fresh snow or mud, TRAC may reduce power
from the engine to the wheels. You may need to turn the system off to
enable you to rock the vehicle in order to free it.
Push the button to turn off TRAC.
The slip indicator light should come
on.
Push the button again to turn the
sy
stem back on.
Once you turn the power switch
“
OFF”, TRAC will be activated
automatically.
■Automatic TRAC reactivation
TRAC is reactivated when vehicle speed exceeds 30 mph (50 km/h) even if
“

TRAC OFF” has been turned off.
■Sounds and vibrations caused by the ABS, BA, VSC, TRAC, hill-start assist con-
trol and VGRS systems
●A sound may be heard from the engine compartment when the hybrid system is
started or just after the vehicle begins to move. This sound does not indicate that
a malfunction has occurred in any of these systems.
●Any of the following conditions may occur when the above systems are operat -
ing. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly af
ter the ABS is activated.
■Hill-start assist control is operational when
●The shift lever is in the “D” or “S” position.
●The brake pedal is not depressed.

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2-4. Using other driving systems
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When driving
PCS (Pre-Collision System) (if equipped)
Radar sensor
Detects vehicles or other obsta-
cles on or near the road ahead and
determines whether a collision is
imminent based on the position,
sp

eed, and heading of the obsta -
cles.
Grille cover
Radar sensor
Safety systems such as the brakes and seat belts are automatically
engaged to lessen impact and injuries to occupants as well as vehicle dam
-
age when the radar sensor detects a
n unavoidable frontal collision.
■Pre-collision seat belts (front seats only)
The seat belts are immediately retracted as the effect of the pretensioner is
increased ( P. 4 4 ), to provide even greater constraining force to protect
the driver and passengers. In the event of sudden braking or skidding, the
s
ystem will operate even if no obstacle has been detected.
■Pre-collision brake assist
Applies greater braking force in relation to how strongly the brake pedal is
depressed.
■ Pre-collision AVS
If the system determines that the collision is unavoidable, the operation of
AV S ( P. 1 6 1 ) helps prevent the vehicle front from going down when hard
brakes are applied.
■Obstacles not detected
The sensor cannot detect plastic obstacles such as pylons. There may also be occa -
sions when the sensor cannot detect pedestrians, animals, bicycles, motorcycles,
tr
ees, or snowdrifts.

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2-4. Using other driving systems
■The pre-collision system is operational when
●Seat belt (linked to the radar sensor)
• Vehicle speed is above 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming vehicle exceeds 18 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Seat belts (linked to brake operation)
• Vehicle speed exceeds 9 mph (15 km/h).
• The system detects sudd en braking or skidding.
• The front occupants are wearing a seat belt.
●Brake Assist
• Vehicle speed is above 18 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming vehicle exceeds 18 mph (30 km/h).
• The brake pedal is depressed.
●AV S
• Vehicle speed is above 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming vehicle exceeds 18 mph (30 km/h).
■Conditions that may trigger the system even if there is no danger of collision
●When there is an object by the roadside at the entrance to a curve
●When passing an oncoming vehicle on a curve
●When driving over a narrow iron bridge
●When there is a metal object on the road surface
●When driving on an uneven road surface
●When passing an oncoming vehicle on a left-turn
●When your vehicle rapidly closes on the vehicle in front
When the system is activated in the situations described above there is also a possi-
bility that the seat belts will retract quickly and the brakes will be applied with a force
greater than normal. When the seat belt is locked in the retracted position, stop the
vehicle in a safe place, release the seat belt and refasten.
■When there is a malfunction in the system
Warning lights and/or warning messages will turn on or flash. ( P. 432, 439)

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2-5. Driving information
2
When driving
■Before driving the vehicle
Perform the following according to the driving conditions.
● D
o not try to forcibly open a w indow or move a wiper that is fro-
zen. Pour warm water over the frozen ar
ea to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● T
o ensure proper operation of the climate control system fan,
remove any snow that has accumulated on the air inlet vents in
front of the windshield.
● R
emove any ice that has accumul ated on the vehicle chassis.
● P
eriodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.
■ When driving the v
ehicle
Accelerate the vehicle slowly and dr iv
e at a reduced speed suitable
to road conditions.
■ When parking the v
ehicle
Park the vehicle and move the shift lever to “P” without setting the
parking br
ake. The parking brake ma y freeze up, preventing it from
being released.