2004 Lexus GX470 suspension

OCCUPANT RESTRAINT SYSTEMS
179
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 574.

OCCUPANT RESTRAINT SYSTEMS
180
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 109.
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
368
STARTING AND DRIVING
Starting and driving
Three-way catalytic converters369
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Engine exhaust caution 372
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Before starting the engine 374
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Ignition switch with steering lock 374
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Parking brake 376
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How to start the engine 377
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Automatic transmission 378
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Four-wheel drive system 386
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Rear view monitor system 390
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Cruise control 394
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Rear height control air suspension 397
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Electronic modulated suspension 404
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Active traction control system 405
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Vehicle stability control system 407
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Downhill assist control system 410
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Hill-start assist control system 413
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Brake system 415
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Tire pressure warning system 419
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Brake pad wear limit indicators 428
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Limited-slip differential 429
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STARTING AND DRIVING
397
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
399
In the following cases, the rear height control suspension
will not operate.

The underbody of the vehicle has touched the surface on
bumpy roads.
 The area around the rear suspension is coated with ice.
If the vehicle is moved to its usual location or the ice is removed
and the height select switch is pressed, the vehicle height
control cannot be operated. In this case, turn off and restart the
engine, then push the control switches.
(c) Vehicle height adjustment

1Higher2Lower
To change the mode, push the height select switch on
either side of  º (higher) or º (lower). The height control indicator light indicates which mode is
selected. (See (e) Height control indicator lightº described
below.)

Selecting the HIº mode
Push the height select switch on the  º side when the vehicle
speed is under about 30 km/h (19 mph).
To change the Nº mode to HIº: Push the switch once.
To change the LOº mode to HIº: Push the switch twice. It
takes about 30 seconds until the LOº mode changes to the HIº
mode.
 Selecting the Nº mode
To change the HIº mode to Nº: Push the height select
switch on the  º side once.
To change the LOº mode to Nº: Push the height select
switch on the  º side once.
 Selecting the LOº mode
Push the height select switch on the º side while the vehicle
is stopped.
To change the Nº mode to LOº: Push the switch once.
To change the HIº mode to LOº: Push the switch twice.
Even if the engine is stopped while the vehicle height is being
lowered, the operation continues for up to 25 seconds. If within
this 25 seconds, any of the side doors or the back door is
opened, operation will continue for a further 15 seconds.

STARTING AND DRIVING
400
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
401
(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
402
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.