wheel Lexus GX470 2007 Using other driving systems /

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2-4. Using other driving systems
■The center differential lock/unlock button can be operated when
●The ignition switch is in the “ON” position, and
●The four-wheel drive control lever is in the “H” or “L” position.
■Locking/unlocking the center differential
●When the center differential is locked, VSC is automatically turned off. (The
center differential lock and “VSC OFF” indicator lights come on.)
●If the operation is not completed, the center differential lock indicator blinks. If
the indicator light does not go off when unlocking the center differential, drive
straight ahead while accelerating or decelerating, or drive in reverse.
●If center differential lock system oper ation is not completed within 5 seconds
while the cruise control system is set, cancel the cruise control system.
CAUTION
■While driving
Never move the four-wheel drive control lever if the wheels are slipping. Doing so
may cause an accident resulting in death or serious injury.
NOTICE
■To prevent damage to the center differential
●Unlock the center differential after the wh eels are out of the ditch or off the loose
or bumpy surface.
●Do not push the center differential lock/u nlock button when the vehicle is corner-
ing or when its wheels are spin ning freely off the ground.

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2-4. Using other driving systems
2
When driving
Electronic modulated suspension
■Driving mode
●Mode is suitable for ordinary driving.
●Mode or is suitable for heavy load or driving on a unpaved road.
●With the four-wheel drive control lever at “L”, the damping effect suitable for off-
road driving will be provided.
The electronic modulated suspension controls the suspension according to
the road and driving conditions. Selected driving mode allows for good
riding comfort and stability.
For driving on a bumpy road
For ordinary driving such as
in the city traffic
For moderate high speed
driving
For sporty type driving such
as on winding mountain
roads and high speed driving.
Soft Hard

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2-4. Using other driving systems
DAC (Downhill Assist Control system)
The DAC system helps to prevent excessive speed on steep downhill
slopes.
The system will operate when the vehicle is traveling under 15 mph
(25km/h) and the four wheel drive control lever is in the “L” position.
■System operation
Press the “DAC” switch. The
indicator will come on, and the
system will operate.
When the system is in operation,
the slip indicator light will flash,
and the stop lights/high
mounted stop lights will be lit.
■Turning off the system
Press the “DAC” switch while the system is in operation. The indica-
tor will flash as the system gradua lly ceases operation, and will turn
off when the system is fully off.
Press the “DAC” switch while the indicator is flashing to start the
system again.

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2-4. Using other driving systems
2
When driving
■Operating tips
The system will operate when the shift lever is in a position other than “P”, however
to make effective use of the system it is recommended that the shift lever be shifted
to “2” or “L”.
■If the four wheel drive control lever is in “H”
The system will not operate.
■If the brake system overheats
The system will cease operation and a bu zzer will sound to alert the driver.
Stop the vehicle in a safe place. (There is no problem with continuing normal driv-
ing.)
■System malfunction
●The “DAC” indicator does not come on when the ignition key is turned to the
“ON” position.
●The “DAC” indicator does not come on when the “DAC” switch is pressed.
In the above cases have your vehicle checked by your Lexus dealer.
CAUTION
■The system may not operate on the following surfaces, which may lead to an acci-
dent causing death or serious injury.
●Slippery surfaces such as wet or muddy roads
●Icy surfaces
●Unpaved roads

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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 when swerving suddenly or turning on
slippery road surfaces.
■ Active traction control
Maintains drive power and prevents the 4 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.
■ LSD (Limited Slip Differential)
Transfers drive power to the rear tires when front tires spin, and vice versa,
in order to improve traction.
■KDSS (Kinetic Dynamic Suspension System) (if equipped)
KDSS helps to significantly enhance handling response by reducing roll
stiffness of the suspension stabilizer bars through means of a hydraulic
control system.

133
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
starting on an incline, 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-start
assist control system is operating.
The slip indicator light flashes as
well when ABS is operating.
■Sounds and vibrations caused by the ABS, BA, VSC, TRAC and hill-start assist
control 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 s lightly after the ABS is activated.
■Hill-start assist control is operational when
●The shift lever is in any of the positions “D”, “4”, “3”, “2” or “L”.
●The brake pedal is not depressed.

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2-4. Using other driving systems
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 the wet or slick road.
■Stopping distance when the ABS is operating on the wet or slick roads
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.
■The hill-start assist control may not operate effectively when
●On steep inclines.
●On icy surfaces.
■When the 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.
■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 ti res are inflated to the specified tire pres-
sure level.
The ABS and VSC will not function correctly if different tires are fitted on the vehi-
cle.
Contact your Lexus dealer for further info rmation when replacing tires or wheels.

138
2-5. Driving information
CAUTION
■Off-road driving precautions
Always observe the following precautions to minimize the risk of serious personal
injury or damage to your vehicle:
●Drive carefully when off the road. Do not take unnecessary risks by driving in
dangerous places.
●Do not grip the steering wheel spokes wh en driving off-road. A bad bump could
jerk the wheel and injure your hands. Keep both hands and especially your
thumbs on the outside of the rim.
●Always check your brakes for effectiveness immediately after driving in sand,
mud, water or snow.
●After driving through tall grass, mud, rock, sand, rivers, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped on the underbody.
Clear off any such matter from the underbody. If the vehicle is used with these
materials trapped or adhering to the underbody, a breakdown or fire could occur.
●When driving off-road or in rugged te rrain, do not drive at excessive speeds,
jump, make sharp turns, strike objects, etc. This may cause loss of control or vehi-
cle rollover causing death or serious injury. You are also risking expensive dam-
age to your vehicle’s suspension and chassis.
NOTICE
■To prevent the water damage
Take all necessary safety measures to ensure that water damage to the engine or
other components does not occur.
●Water entering the engine air intake will cause severe engine damage.
●Water entering the automatic transmission will cause deterioration in shift quality,
locking up of your transmission accompanied by vibration, and ultimately dam-
age.
●Water can wash the grease from wheel bearings, causing rusting and premature
failure, and may also enter the differentials, transmission and transfer case, reduc-
ing the gear oil’s lubricating qualities.

146
2-5. Driving information
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 w indow 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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2-5. Driving information
■Snow chain installation
Observe the following precautions when installing and removing chains.
●Install and remove tire chains in a safe location.
●Install tire chains on the rear tires.
●Install tire chains in accordance with the accompanying instructions.
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 65 mph (105 km/h), regardless of the type of snow tires
being used.
●Snow tires should be installed on all 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.