2004 Lexus GX470 air suspension

OCCUPANT RESTRAINT SYSTEMS
189
Do not use seat accessories which cover the parts
where the side airbags inflate. 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
Checking and replacing tiresº on page 594.

OCCUPANT RESTRAINT SYSTEMS
190
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 Roof luggage
carrierº on page 119.
Failure to follow these instructions can result in death
or serious injury. Consult your Lexus dealer about any
repair and modification.
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 compact disc
player
Modification of the suspension system
Modification of the structure of the passenger compartment
Repairs made on or near the console or front seat

SECTION 3 ± 1
383
STARTING AND DRIVING
Starting and driving
Three-way catalytic converters384
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Engine exhaust caution 387
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Before starting the engine 389
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Ignition switch with steering lock 389
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Parking brake 391
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How to start the engine 392
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Automatic transmission 393
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Four-wheel drive system 401
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Rear view monitor system 405
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Cruise control 409
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Rear height control air suspension 412
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Electronic modulated suspension 419
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Active traction control system 420
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Vehicle stability control system 422
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Downhill assist control system 425
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Hill-start assist control system 428
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Brake system 430
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Tire pressure warning system 434
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Brake pad wear limit indicators 444
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Limited-slip differential 445
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STARTING AND DRIVING
412
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 HIº (high), Nº
(normal) and LOº (low) modes with the height select
switch.
(a) Vehicle height modes
Nº (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. HIº
(high) mode: The vehicle height is about 40 mm (1.6 in.)
higher at the rear than the Nº 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 HIº mode, the Nº mode is automatically
selected.
CAUTION
The HIº 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.
LOº (low) mode: The vehicle height is about 20 mm (0.8 in.)
lower at the rear than the Nº 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
415
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 LOº mode in the bumpy roads. Ifthe underbody of the vehicle touches the ruggedroad surface, the vehicle may be damaged.

STARTING AND DRIVING
416
(d) Turning off the rear height control airsuspension
To turn off the rear height control air suspension with the
vehicle stopped, push the HEIGHT CONTROL OFFº
switch. The height control OFFº 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 OFFº 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 HEIGHT CONTROL OFFº switch, if the vehicle speed
exceeds 30 km/h (19 mph), the rear height control air
suspension automatically selects the Nº mode.
CAUTION
If you drive through deep water over about 700 mm (28
in.) in depth, put the vehicle height in the HIº mode with
the height select switch and then turn off the rear height
control air suspension by pushing the HEIGHT
CONTROL OFFº switch.

STARTING AND DRIVING
417
NOTICE
When jacking up or installing tire chains, be sure toturn off the rear height control air suspension withthe HEIGHT 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 Nº 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 HEIGHT CONTROLOFFº switch. Otherwise, the vehicle height maychange because of the automatic leveling functionresulting in accident.

STARTING AND DRIVING
418
(e) Height control indicator lights

1Height control indicator lights
2Height control OFFº 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 Nº mode to
HIº:
1. The Nº mode indicator light goes off and the HIº mode
indicator light blinks.
2. After the vehicle height control reaches the HIº mode, the
HIº 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 OFFº 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 HEIGHT CONTROL OFFº switch,
the rear height control air suspension is turned off. The height
control OFFº 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 OFFº indicator light does not come on
when the ignition switch is turned on.
 The height control OFFº indicator light blinks.