2008 Lexus GX470 suspension

154
2-4. Using other driving systems
CAUTION
Failure to observe the following precautions may result in an accident.
■ Using the “HI” (high) mode
This mode should only be used for rough off-road conditions. Because the vehicle’s
center of gravity is higher when in the high mode, the vehicle may become unstable
when turning abruptly.
■When loading cargo on the roof luggage carrier
Do not select the “HI” (high) mode. Because the vehicle’s center of gravity is higher
when in the high mode, the vehicle may become unstable when turning abruptly
and unexpected loss of control or vehicle rollover may occur.
■When jacking up the vehicle or installing tire chains
Turn off the rear height control air suspension and stop the engine, otherwise the
vehicle height may change due to the automatic leveling function.
■ When driving through water deeper than 28 in. (700 mm)
Select the “HI” (high) mode, turn off the rear height control air suspension and drive
at 19 mph (30 km/h) or slower. Otherwise, the vehicle height may change due to
the automatic leveling function.
■If your vehicle must be towed
Put the vehicle height in the normal mode and turn off the rear height control air
suspension, otherwise the vehicle height may change due to the automatic leveling
function.
■If your vehicle becomes stuck in a ditch
Turn off the rear height control air suspension, otherwise the vehicle height may
change due to the automatic leveling function.

156
2-4. Using other driving systems
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
2
When driving
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.
■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.
■Limited Slip Differential
Transfers drive power to the rear tires when front tires spin, and vice versa,
in order to improve traction.
■Kinetic Dynamic Suspension System (if equipped)
Kinetic Dynamic Suspension System helps to significantly enhance han-
dling response by reducing roll stiffness of the suspension stabilizer bars
through means of a hydraulic control system.

162
2-4. Using other driving systems
CAUTION
■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 VSC will not function correctly if different tires are fitted on the vehi-
cle.
Contact your Lexus dealer for further information 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.

166
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 when 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 terrain, 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.

179
2-5. Driving information
2
When driving
NOTICE
■Repairing or replacing snow tires
Request repairs of and obtain replacement snow tires from Lexus dealer.
This is because the removal and attachment of snow tires affects the operation of
the tire pressure warning valves and transmitters.
■When jacking up or installing tire chains
Be sure to turn off the rear height control air suspension and stop the engine.
Otherwise, the vehicle height may change because of the automatic leveling func-
tion, resulting in an accident.
■Fitting tire chains
The tire pressure warning valves and transmitters may not function correctly when
tire chains are fitted.

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2-5. Driving information
2
When driving
Connecting trailer lightsUse the wire harness stored in the rear end underbody.
■When connecting and disconnecting a trailer Connecting
Set the rear height control air suspension to “LO” mode.
Turn off the engine switch or the rear height control air suspension.
Connect the trailer.
Turn on the switch that was turned off on STEP 2.
Set the rear height control air suspension to “N” mode.
Disconnecting
Set the rear height control air suspension to “LO” mode.
Turn off the engine switch or the rear height control air suspension.
Set the supporting leg of the trailer on the ground and raise the hitch by
4 in. (100 mm).
Turn on the switch that was turned off on STEP 2.
Wait until vehicle height is stabilized.
Make sure the hitch is disconnected. If the hitch does not disconnect, raise
the hitch higher and repeat steps 2 through 5.
Move the vehicle forward in the “LO” mode where the hitch does not
touch anything in the “N” mode.
Set the rear height control air suspension in the “N” mode.
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4
STEP1STEP5STEP5STEP5
STEP1STEP1
STEP2STEP2
STEP1STEP3STEP3
STEP1STEP4STEP4
STEP1STEP5STEP5STEP5
STEP1STEP5STEP6STEP6STEP6
STEP1STEP5STEP6STEP7STEP7
STEP1STEP5STEP6STEP8STEP8

184
2-5. Driving information
■Before towing
Check that the following conditions are met:
●The vehicle’s tires are properly inflated. (→P. 4 1 9 )
●Trailer tires are inflated according to the trailer manufacturer’s recommenda-
tion.
●All trailer lights work.
●All lights work each time you connect them.
●The trailer ball is set up at the proper height for the coupler on the trailer.
●The vehicle remains level when a loaded or unloaded trailer is hitched. Do not
drive if the vehicle is not level, and check for improper tongue load, overloading,
worn suspension, or other possible causes.
●The trailer cargo is securely loaded.
●The rear view mirrors conform to all applicable federal, state/provincial or local
regulations. If they do not, install rear view mirrors appropriate for towing pur-
poses.
■Break-in schedule
Lexus recommends that you do not use a new vehicle or a vehicle with any new
power train components (engine, transmission, differential, wheel bearings, etc.) to
tow a trailer for the first 500 miles (800 km) of driving.
■Maintenance
●If you tow a trailer, your vehicle will require more frequent maintenance due to
the additional load. (See “Warranty and Services Guide/Owner’s Manual Sup-
plement/Scheduled Maintenance”.)
●Retighten the fixing bolts of the towing ball and bracket after approximately
600 miles (1000 km) of trailer towing.