wheel Lexus GS350 2009 Service Manual

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AVS (Adaptive Variable Suspension System)∗
∗: If equipped
AVS controls the suspension according to the road and driving conditions.
Selecting an optimum driving mode allows good vehicle posture and steer-
ing wheel operation in conjunction with VGRS (GS460), EPS and active
stabilizer suspension system (if equipped).
Sports mode
For winding mountain road driv-
ing or high speed driving.
Normal mode
For normal driving.
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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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■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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Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■ Pre-winter preparations
●Use fluids that are appropria te to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific gravity of
battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the rear tires.
Ensure that all tires are the same size and brand, and that chains match
the size of the tires.
■ Before driving the vehicle
Perform the following according to the driving conditions.
● Do not try to forcibly open a window or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To ensure proper operation of the climate control system fan,
remove any snow that has accumu lated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumul ated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.
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Regulations on the use of tire chains● Regulations regarding the use of tire chains vary according to location
and type of road. Alwa ys check local regulations before installing
chains.
● Use SAE Class “S” type radial tire chains, with the exception of radial
cable chains or V-bar type chains.
• Install the chains on the rear tires.
• Refer to the explanation that comes with the tire chains for installa-
tion instructions.
● Retighten the chains after driving 1 /4 - 1 /2 mile (0.5 - 1.0 km).
■When driving the vehicle
Accelerate the vehicle slowly and dr ive at a reduced speed suitable
to road conditions.
■ When parking the vehicle
Park the vehicle and move the shift lever to “P” without setting the
parking brake. The parking brake may freeze up, preventing it from
being released. If necessary, bl ock the wheels to prevent inadvert-
ent sliding or creeping.
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CAUTION
■Driving with snow tires
Observe the following precautions to reduce the risk of accidents.
Failing to do so may result in a loss of vehicle control and cause death or serious
injury.
●Use tires of the size specified for your vehicle.
●Maintain the specified level of tire inflation 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.
■Driving with snow chains
Observe the following precautions to reduce the risk of accidents.
Failing 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 turns and braking, as use of chains may adversely affect vehicle
handling.
●Slow down sufficiently before entering a curve to ensure that vehicle control is
maintained.
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