2015 Lexus GS450h steering

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4-5. Using the driving support systems
●When driving on winding roads or roads that are uneven
●When driving on rough or unpaved roads
■When changing the tires
Depending on the tires used, sufficient performance may not be maintainable.
■Warning messages for LKA
Warning messages are used to indicate a system malfunction or to inform the driver
of the need for caution while driving. (P. 5 1 6 , 5 2 6 )
CAUTION
■Before using the LKA system
Do not rely solely on the LKA system. The LKA system does not drive the vehicle
automatically, nor does it reduce the amount of care you need to take. As such, the
driver must always assume full responsi bility for understanding his/her surround-
ings, for operating the steering wheel to correct the driving line, and for driving
safely.
Inappropriate or negligent driving could lead to an accident.
■To avoid operating the LKA by mistake
Switch the LKA off using the “LKA” switch when not in use.

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Sport mode• SPORT S mode
Assists acceleration response by controlling the hybrid system.
When not in SPORT S mode and the driving mode select switch is turned to
the right, the “SPORT S” indicator comes on in the multi-information display,
and the Hybrid System Indicator changes to the tachometer. (P. 9 1 )
Also, on vehicles equipped with a
12.3-inch display, the driving mode
is also automatically displayed on
the side display. ( P. 3 3 2 )
• SPORT S+ mode
Helps to ensure steering performa nce and driving stability by simul-
taneously controlling the steering an d suspension in addition to the
hybrid system. Suitable for sporty driving.
When in SPORT S mode and the driving mode select switch is turned to the
right, the “SPORT S+” indicator comes on in the multi-information display, and
the Hybrid System Indicator changes to the tachometer. (P. 9 1 )
Also, on vehicles equipped with a
12.3-inch display, the driving mode
is also automatically displayed on
the side display. ( P. 3 3 2 )
3

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Driving assist systems
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while dri ving on a slippery road surface
◆Brake assist
Generates an increased level of br aking 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 when swerving suddenly or turning
on slippery road surfaces
◆Enhanced VSC (Enhanced Vehicle Sta bility Control) (if equipped)
Provides cooperative control of the ABS, TRAC, VSC and EPS.
Helps to maintain directional stability when swerving on slippery road
surfaces by controllin g steering performance.
◆TRAC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from spin-
ning when starting the vehicle or accelerating on slippery roads
◆VGRS (Variable Gear Ratio Steering) (if equipped)
Adjusts the front wheel turning angl e in accordance with the vehicle
speed and steering wheel movement
To help enhance driving safety an d 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.

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Driving
◆DRS (Dynamic Rear Steering) (if equipped)
Contributes to the turning characteristics and responsiveness of the
vehicle by slightly adjusting the rear wheel angle of the vehicle in accor-
dance with steering wheel movement
◆EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to
turn the steering wheel
◆AVS (Adaptive Variable Suspension system)
By independently controlling the damping force of the shock absorbers
for each of the 4 wheel s according to the road and driving conditions,
this system helps riding comfort with superior steering stability, and
helps good vehicle posture
When SPORT S+ mode is selected by the driving mode select switch,
the damping force is suitable for sporty driving ( P. 2 8 1 )
◆LDH (Lexus Dynamic Handlin g system) (if equipped)
Provides independent control of the VGRS, DRS and EPS. Contributes
to turning characteristics at low speeds, responsiveness at medium
speeds and safety at high speeds by controlling the steering angle of
the front and rear wheels in accorda nce with the steering wheel opera-
tion and vehicle speed
◆VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, TRAC, VSC and
EPS, VGRS (if equipped) and DRS (if equipped) systems
Helps to maintain vehicle stability when swerving on slippery road sur-
faces by controlling the brakes, hybr id system output, steering assist,
and steering ratio
◆PCS (Pre-Collision System) (if equipped)
 P. 2 9 1

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■When the message is displayed on the multi-information display showing that
TRAC has been disabled even if the VSC OFF switch has not been pressed
TRAC cannot be operated. Contact your Lexus dealer.
■VGRS is disabled when
VGRS may stop operating in the following situations.
In this event, the steering wheel may move from its straight forward position, but it
will return when the system restarts.
●The steering wheel is operated for an extended period of time while the vehicle is
stopped or is moving very slowly.
●When force is continuously applied for a long time with the steering wheel turned
as far as it will go.
The center position of the steering wheel may change when VGRS is disabled. How-
ever, the position will return to normal after VGRS is reactivated.
■When the battery is disconnected
The steering wheel may move from its straight forward position, but this will be cor-
rected automatically when driving.
■Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and VGRS sys-
tems
●A sound may be heard from the engine compartment when the brake pedal is
depressed repeatedly, when the hybrid syst em 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 operating.
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.
■EPS, VGRS and DRS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
■Reactivation of the TRAC/VSC systems
Even after the TRAC/VSC systems have been turned off, turning the hybrid system
off and then on again will automatically reactivate the TRAC/VSC systems.
■Reactivation of the TRAC sy stem linked to vehicle speed
When only the TRAC system is turned off, the TRAC system will turn on when vehi-
cle speed increases. However, when both TRAC/VSC systems are turned off, the
systems will not turn on even when vehicle speed increases.

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Driving
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from overheat-
ing when there is frequent steering input over an extended period of time. The steer-
ing wheel may feel heavy as a result.
* Should this occur, refrain from excessive
steering input or stop the vehicle and tu rn the hybrid system off. The EPS system
should return to normal within 10 minutes.
*: If the LKA (Lane-Keeping Assist) system cannot operate in this case, a warning
message will be shown on the multi-information display.
CAUTION
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded. (such as excessively
worn tires on a snow covered road).
●The vehicle hydroplanes while driving at high speed on wet or slick roads.
■Stopping distance when the ABS is operating may exceed that of normal condi-
tions
The ABS is not designed to shorten the ve hicle’s stopping distance. Always main-
tain a safe distance from the vehicle in front of you, especially in the following situa-
tions:
●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 uneven surfaces
■TRAC may not operate effectively when
Directional control and power may not be achievable while driving on slippery
road surfaces, even if the TRAC system is operating.
Drive the vehicle carefully in conditions where stability and power may be lost.
■When the VSC is activated
The slip indicator light flashes. Always drive carefully. Reckless driving may cause
an accident. Exercise particular care when the indicator light flashes.
■When the TRAC/VSC systems are turned off
Be especially careful and drive at a spee d appropriate to the road conditions. As
these are the systems to help ensure vehicle stability and driving force, do not turn
the TRAC/VSC systems off unless necessary.

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◆Suspension control
When the system determines that there is a high possibility of a frontal
collision, the operation of AVS ( P. 285) optimally controls the damp-
ing force of the shock absorber.
◆Steering control (if equipped)
Vehicles with VGRS
There is a high possibility of collisi on and if the steering wheel is oper-
ated, the steering gear ratio is chan ged by VGRS to help improve the
response to steering input.
Vehicles with LDH
There is a high possibility of collisi on and if the steering wheel is oper-
ated, the steering angles of the fr ont and rear wheels and the heaviness
of the steering wheel are controlled by LDH, thus heightening respon-
siveness in response to the steering operation.
◆Driver monitor system (if equipped)
When the system determines that there is a possibility of a collision, and
either the driver is not facing forwar d or the driver’s eyes are closed,
PCS warnings are given in advance to warn the driver. If the system
determines that the conditions to operate pre-collision alert braking
have been met even when the possib ility of a collision increases further,
pre-collision alert braking will operate.

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Driving
■The pre-collision system is operational when
The PCS OFF switch is not pressed and the following conditions are met:
●Pre-collision warning:
• Vehicle speed is greater than about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle run-ning ahead of you is greater than about 10 mph (15 km/h).
●Pre-collision seat belts (operating conditions A):
• Vehicle speed is greater than about 19 mph (30 km/h).
• The system detects sudd en braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (operating conditions B):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle run- ning ahead of you is greater than about 19 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision brake assist:
• Vehicle speed is greater than about 19 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle run- ning ahead of you is greater than about 19 mph (30 km/h).
• The brake pedal is depressed.
●Pre-collision braking:
• Vehicle speed is greater than about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle run- ning ahead of you is greater than about 10 mph (15 km/h).
●Suspension control:
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle run-ning ahead of you is greater than about 19 mph (30 km/h).
●Pre-collision alert braking:
• The system determines that the driver is not facing forward, or that the driver’s
eyes are closed.
• Vehicle speed is greater than about 25 mph (40 km/h).
• The speed at which your vehicle is approaching the vehicle running ahead of
you is greater than about 25 mph (40 km/h).
• The steering is not being turned.