2005 Lexus GX470 air suspension

OCCUPANT RESTRAINT SYSTEMS
190
Do not use seat accessories which cover the parts
where the side airbags infla te. Such accessories may
prevent the side airbags from activating correctly,
causing death or serious injury.
 Do not modify or replace the seats or upholstery of
the seats with side airbags. Such changes may
prevent the side airbag system form activating
correctly, disable the system or cause the side
airbags to inflate accidentally, resulting in death or
serious injury.
 Do not disassemble or repair the front and rear pillars
and roof side rails containing the curtain shield
airbags. Such changes may disable the system or
cause the curtain shield airbags to inflate
accidentally, resulting in death or serious injury.
 Do not modify or change the suspension system.
Such changes may cause the curtain shield airbags
to inflate accidentally, which could result in death or
serious injury. Consult your Lexus dealer about any
repair and modification.
 Do not use tires or wheels other than the
manufacture's recommended size. Such a use may
cause the curtain shield airbags and seat belt
pretensioners to inflate accidentally, which could
result in death or serious injury. For details, see
ªChecking and replacing tiresº on page 589.

OCCUPANT RESTRAINT SYSTEMS
191
Do not place luggage heavier than specified on the
roof luggage carrier. Such luggage may cause the
curtain shield airbags and seat belt pretensioners to
inflate accidentally, which could result in death or
serious injury. For details, see ªRoof luggage
carrierº on page 120.
Failure to follow these instructions can result in death
or serious injury. Consult your Lexus dealer about any
repair and modification.
If you wish to modify your vehicle for a person with a
physical disability, consult your Lexus dealer. It may
dangerously interfere with the SRS side airbags and
curtain shield airbags operation.
NOTICE
Do not perform any of the following changes without consulting your Lexus dealer. Such changes caninterfere with proper operation of the SRS side airbagand curtain shield airbag system in some cases.
Installation of electronic devices such as a mobiletwo±way radio, cassette tape player or CD player
Modification of the suspension system
Modification of the structure of the passengercompartment
Repairs made on or near the console or front seat

SECTION 3 ± 1
392
STARTING AND DRIVING
Starting and driving
Three±way catalytic converters393
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Engine exhaust caution 396
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Before starting the engine 398
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Ignition switch 398
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Parking brake 400
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How to start the engine 401
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Automatic transmission 403
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Four±wheel drive system 411
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Rear view monitor system 415
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Cruise control 419
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Rear height control air suspension 422
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Electronic modulated suspension 429
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Active traction control system 430
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Vehicle stability control system 433
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Downhill assist control system 436
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Hill±start assist control 439
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Brake system 442
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Tire pressure warning system 446
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Brake pad wear limit indicators 456
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Limited±slip differential 457
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STARTING AND DRIVING
422
REAR HEIGHT CONTROL AIRSUSPENSION
This rear height control air suspension controls the
vehicle height depending on the vehicle driving condition.
Select your desired height among the ªHIº (high), ªNº
(normal) and ªLOº (low) modes with the height select
switch.
(a) Vehicle height modes
ªNº (normal) mode: The vehicle height in this mode is
standard. Regardless of the number of occupants or the
luggage loading condition, the vehicle height is always
automatically adjusted to a fixed height in any mode while the
engine is running.
This mode is suitable for ordinary driving. ªHIº
(high) mode: The vehicle height is about 40 mm (1.6 in.)
higher at the rear than the ªNº mode height.
This mode is suitable when driving on the bumpy roads and
through water.
However, when the vehicle speed exceeds about 30 km/h (19
mph) or over in the ªHIº mode, the ªNº mode is automaticall\
y
selected.
CAUTION
The ªHIº mode should be used for severe off±road
driving condition only. As the vehicle's center of gravity
is higher in this setting, the vehicle may become
unstable when turning abruptly resulting in accident.
ªLOº (low) mode: The vehicle height is about 20 mm (0.8 in.)
lower at the rear than the ªNº mode height.
This mode allows you easy access to the vehicle (getting in and
out) and easy loading and unloading operation.
This mode is available when the vehicle speed is under about
12 km/h (7 mph).

STARTING AND DRIVING
425
NOTICE
If the vehicle height is changed frequently when thevehicle is heavily loaded, the compressor mayoverheat causing the vehicle height adjustmentoperation to stop.
Before you lower the vehicle height with the heightselect switch, check under the vehicle to make surenothing to dam age the vehicle or no one to be injured
is there and that the underbody of the vehicle does not touch the ground.
After unloading, the height of a vehicle equipped with
the rear height control air suspension becomes
slightly higher than the normal vehicle height. Takesufficient care where the overhead height isrestricted.
Do not select the ªLOº mode in the bumpy roads. Ifthe underbody of the vehicle touches the ruggedroad surface, the vehicle may be damaged.

STARTING AND DRIVING
426
(d) Turning off the rear height control airsuspension
To turn off the rear height control air suspension with the
vehicle stopped, push the ªHEIGHT CONTROL OFFº
switch. The height control ªOFFº indicator light comes on
and the vehicle height is fixed in the same mode as the
height control switch is pushed.
This status is memorized in the system even after the engine
is stopped.
If you push the switch again, the height control ªOFFº indicator
light goes out and the rear height control air suspension is
turned on.
Even after the rear height control air suspension is turned off
with the ªHEIGHT CONTROL OFFº switch, if the vehicle speed
exceeds 30 km/h (19 mph), the rear height control air
suspension automatically selects the ªNº mode.
CAUTION
If you drive through deep water over about 700 mm (28
in.) in depth, put the vehicle height in the ªHIº mode with
the height select switch and then turn off the rear height
control air suspension by pushing the ªHEIGHT
CONTROL OFFº switch.

STARTING AND DRIVING
427
NOTICE
When jacking up or installing tire chains, be sure toturn off the rear height control air suspension withthe ªHEIGHT CONTROL OFFº switch and stop theengine. Otherwise, the vehicle height may changebecause of the automatic leveling function resultingin accident.
If your vehicle must be towed, put the vehicle heightin the ªNº mode and turn off the rear height control airsuspension. Otherwise, the vehicle height may
change because of the automatic leveling functionresulting in accident.
If your vehicle gets ditched, turn off the rear heightcontrol air suspension with the ªHEIGHT CONTROLOFFº switch. Otherwise, the vehicle height maychange because of the automatic leveling functionresulting in accident.

STARTING AND DRIVING
428
(e) Height control indicator lights

1Height control indicator lights
2Height control ªOFFº indicator light
When the ignition switch is turned on, all the indicator lights
come on. Only the indicator light showing the present mode
remains on and all other lights go off after a few seconds. This
means the system operates correctly.
When you change the vehicle height mode, the indicator lights
change as follows:
When changing the vehicle height from the ªNº mode to
ªHIº:
1. The ªNº mode indicator light goes off and the ªHIº mode
indicator light blinks.
2. After the vehicle height control reaches the ªHIº mode, the
ªHIº mode indicator light remains on. If the underbody of the vehicle has touched the surface on
bumpy roads or the area around the rear suspension is
coated with ice, the height control suspension will not
operate and the indicator lights change as follows:
1. The present mode indicator light goes off and the selected
mode indicator light blinks.
2. The selected mode indicator light goes off. (The vehicle
height does not change.) The present mode indicator light
comes on again.
Height control ªOFFº indicator light: When the ignition
switch is t
urned on, this light comes on. If it goes out after a few
seconds, the rear height control air suspension operates
correctly. If you push the ªHEIGHT CONTROL OFFº switch,
the rear height control air suspension is turned off. The height
control ªOFFº indicator light comes on.
In the following cases, there is a problem somewhere in the
rear height control air suspension. Although there is no
problem to continue normal driving, have the rear height
control air suspension checked by your Lexus dealer as soon
as possible.
 The height control ªOFFº indicator light does not come on
when the ignition switch is turned on.
 The height control ªOFFº indicator light blinks.