steering Lexus GS350 2014 Using the air conditioning system and defogger / LEXUS 2014 GS350 (OM30D41U) Service Manual

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4-5. Using the driving support systems
CAUTION
■When using the rear view monitor system
The rear view monitor system is a supplemental device intended to assist the driver
when backing up. When backing up, be sure to check visually behind and all
around the vehicle before proceeding.
Observe the following precautions to avoid an accident that could result in death
or serious injuries.
●Never depend on the rear view monitor system entirely when backing up. The
image and the position of the guide lines displayed on the screen may differ from
the actual state.
Use caution, just as you would when backing up any vehicle.
●Be sure to back up slowly, depressing the brake pedal to control vehicle speed.
●The instructions given are only guidelines.
When and how much to turn the steering wheel will vary according to traffic con-
ditions, road surface conditions, vehicle condition, etc. when parking. It is neces-
sary to be fully aware of this before using the rear view monitor system.
●When parking, be sure to check that the parking space will accommodate your
vehicle before maneuvering into it.
●Do not use the rear view monitor system in the following cases:
• On icy or slick road surfaces, or in snow
• When using tire chains or the compact spare tire
• When the trunk lid is not closed completely
• On roads that are not flat or straight, such as curves or slopes.
●In low temperatures, the screen may darken or the image may become faint. The
image could distort when the vehicle is moving, or you may become unable to
see the image on the screen. Be sure to check direct visually and with the mirrors
all around the vehicle before proceeding.
●If the tire sizes are changed, the position of the fixation guide lines displayed on
the screen may change.
●The camera uses a special lens. The di stances between objects and pedestrians
that appear in the image displayed on th e screen will differ from the actual dis-
tances. ( P. 2 5 6 )

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Driving
Sport mode
Assists acceleration response by controlling the transmission and
steering. Suitable for when precise handling is desirable, for example
when driving on mountain roads.
When not in sport mode and the driving mode select switch is turned to the right,
the “SPORT” indicator comes on in the multi-information display.
Also, on vehicles equipped with a
12.3-inch display, the driving mode is
also automatically displayed on the
“Side Display”. ( P. 3 1 4 )
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Driving
Sport mode• SPORT S mode
Assists acceleration response by controlling the transmission.
When not in SPORT S mode and the driving mode select switch is turned to
the right, the “SPORT S” indicator come s on in the multi-information display.
Also, on vehicles equipped with a
12.3-inch display, the driving mode
is also automatically displayed on
the “Side Display”. ( P. 3 1 4 )
• 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
transmission. 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.
Also, on vehicles equipped with a
12.3-inch display, the driving mode
is also automatically displayed on
the “Side Display”. (P. 3 1 4 )
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Driving
Driving assist systems
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lo ck 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 Stability Control)
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
◆Hill-start assist control
P. 2 7 7
◆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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◆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) (if equipped)
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. 266)
◆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 AB S, brake assist, TRAC, VSC, hill-
start assist control, 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, engine output, steering assist, and
steering ratio and rear wheel angle
◆PCS (Pre-Collision System) (if equipped)
 P. 279

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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 engine is started or
just after the vehicle begins to move. This sound does not indicate that a malfunc-
tion 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 engine off and
then on again will automatically reactivate the TRAC/VSC systems.

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■Reactivation of the TRAC system 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.
■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 ov er 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 engine 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.

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◆Suspension control (if equipped)
When the system determines that there is a high possibility of a frontal
collision, the operation of AVS ( P. 270) 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 possibility of a collision increases further,
pre-collision alert braking will operate.

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■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).
●Steering control:
• 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).
●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.

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4-6. Driving tips
CAUTION
■Driving with snow tires
Observe the following precautions to reduce the risk of accidents.
Failure to do so may result in a loss of vehicle control and cause death or serious
injury.
●Use tires of the specified size.
●Maintain the recommended level of air pressure.
●Do not drive in excess of 75 mph (120 km/h), regardless of the type of snow tires
being used.
●Use snow tires on all, not just some wheels.
●Do not use LKA (Lane-Keeping Assist) system.
■Driving with tire chains (vehicles with front and rear tires of the same size except
for the vehicles with LDH and 19 inch tires)
Observe the following precautions to reduce the risk of accidents.
Failure to do so may result in the vehicle being unable to be driven safely, and may
cause death or serious injury.
●Do not drive in excess of the speed limit specified for the tire chains being used,
or 30 mph (50 km/h), whichever is lower.
●Avoid driving on bumpy road surfaces or over potholes.
●Avoid sudden acceleration, abrupt steering, sudden braking and shifting opera-
tions that cause sudden engine braking.
●Slow down sufficiently before entering a curve to ensure that vehicle control is
maintained.
●Do not use LKA (Lane-Keeping Assist) system.