2009 Lexus GS350 Owner's Manual

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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)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while driving on a slippery road surface.
■Brake assist
Generates an increased level of braking force after the brake pedal is
depressed, when the system detects a panic stop situation.
■Enhanced VSC (Enhanced Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or turning on
slippery road surfaces.
■ TRAC (Traction Control)
Helps to maintain drive power and prev ents 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 operates for approximately 5 seconds at maxi-
mum.
■ EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.
■Active stabilizer suspension system (if equipped)
Reduces sway when cornering accord ing to steering wheel movement
and the selected suspension damping mode, in order to maintain a stable
vehicle posture.
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When the Enhanced VSC/TRAC/hill-start assist control systems are
operatingIf the vehicle is in danger of slip-
ping, rolling backwards when
starting on an incline, or if the rear
wheels (2WD models) or all
wheels (4WD models) spin, the
slip indicator light flashes to indi-
cate that the Enhanced VSC/
TRAC/hill-start assist control sys-
tems have been engaged.
A buzzer (intermittent) sounds to
indicate that Enhanced VSC is
operating.
The stop lights and high mounted
stoplight turn on when the hill-start
assist control system is operating.
GS460: The slip indicator lightflashes as well when
ABS is operating.
■PCS (Pre-Collision System) (if equipped)
→ P. 2 0 7
■VGRS (Variable Gear Ratio Steering) (GS460)
Adjusts the wheel turning angle in accordance with the vehicle speed and
steering wheel movement.
■VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, Enhanced VSC, TRAC, hill-start
assist control, VGRS (GS460) and EPS systems.
Helps to maintain vehicle stability when swerving on slippery road sur-
faces by controlling the brakes, engine output, and the movement of the
front wheels.
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To disable TRAC and/or Enhanced VSCIf the vehicle gets stuck in fresh snow or mud, TRAC and Enhanced VSC
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.
■ Turning off TRAC only
Quickly push and release the but-
ton to turn off TRAC.
The message “TRAC OFF”
appears on the multi-information
display.
Push the button again to turn the
system back on.
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■Turning off both TRAC and Enhanced VSC
Push and hold the button for more
than 3 seconds while the vehicle is
stopped to turn off TRAC and
Enhanced VSC.
The slip off indicator light should
come on and the message “TRAC
OFF” appears on the multi-infor-
mation display.
Push the button again to turn the
system back on.
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■Automatic reactivation of TRAC and Enhanced VSC
Turning the “ENGINE START STOP” switch OFF after turning off the TRAC and
Enhanced VSC systems will automatically re-enable them.
■Automatic TRAC reactivation
If only the TRAC system is turned off, th e TRAC system will turn on when the vehi-
cle speed increases.
■Automatic TRAC and Enhanced VSC reactivation
If the TRAC and Enhanced VSC systems are turned off, the systems will not turn on
even when the vehicle speed increases.
■Sounds and vibrations caus ed by the ABS, brake assist, Enhanced VSC, TRAC,
hill-start assist control and VGRS (GS460) systems
●A sound may be heard from the engi ne compartment when the engine 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 after the ABS is activated.
■Hill-start assist control operating conditions
This system comes into operation under the following conditions after the brake
pedal has been depressed and the vehicle has come to a stop:
●The shift lever is in the “D” or “S”.
●The system has detect ed that the vehicle is moving backwards.
●GS350: The brake pedal is not depressed.
■EPS operation sound
When the steering wheel operates, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
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■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating when
there is frequent steering input over an extended period of time. The steering wheel
may feel heavy as a result. Should this occur, refrain from excessive steering input or
stop the vehicle and turn the engine off. The system should return to normal about
10 minutes.
■GS460: VGRS is disabled in the following situations
●During stopping or the st eering wheel has been moved for a long time while
driving at lower speeds.
●After the engine is restarted at less than -22°F (-30°C).
CAUTION
Any of the following conditions may result in an accident which could cause death or
serious injury:
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded.
●The vehicle hydroplanes while driving at high speed on a wet or slick road.
■Stopping distance when the ABS is operating will exceed that of normal condi-
tions
The ABS is not designed to shorten the vehicle’s stopping dist ance. Always main-
tain a safe distance from the vehicle in front of you in the following situations.
●When driving on dirt, gravel or snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes or roads with uneven roads
■TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC is operating.
Do not drive the vehicle in conditions where stability and power may be lost.
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CAUTION
■The hill-start assist control may not operate effectively when
●On steep inclines.
●On icy surfaces.
■When the Enhanced VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■When TRAC and Enhanced VSC are off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are systems to ensure vehicle stability and driving force, do not turn off TRAC
and Enhanced VSC unless necessary.
■Replacing tires
Make sure that all tires are of the same size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the specified tire pres-
sure level.
The ABS and Enhanced VSC will not function correctly if different tires are fitted on
the vehicle.
Contact your Lexus dealer for further info rmation when replacing tires or wheels.
■Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will affect the driv-
ing assist systems, and may cause the system to malfunction.
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PCS (Pre-Collision System)∗
Radar sensorDetects vehicles or other obsta-
cles on or near the road ahead and
determines whether a collision is
imminent based on the position,
speed, 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 an unavoidable frontal collision.
■Pre-collision seat belts (front seats only)
If the pre-collision sensor detects that a collision is unavoidable, the pre-
collision system will retract the seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses
control of the vehicle. ( →P. 6 5 )
■Pre-collision brake assist
Applies greater braking force in relation to how strongly the brake pedal is
depressed.
■AVS (if equipped)
If the system determines that the collision is unavoidable, the operation of
AV S ( →P. 199) helps prevent the vehicle front from going down when
hard brakes are applied.
∗: If equipped
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