2006 Lexus GX470 air suspension

OCCUPANT RESTRAINT SYSTEMS
166
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
carrier” on page 107.
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 can
interfere with proper operation of the SRS side airbag
and curtain shield airbag system in some cases.
 Installation of electronic devices such as a mobile
twoway radio, cassette tape player or CD player
 Modification of the suspension system
 Modification of the structure of the passenger
compartment
 Repairs made on or near the console or front seat
The indicator comes on when the ignition key is turned to
the “ON” position. It goes off after about 6 seconds. This
means the SRS side airbags and curtain shield airbags are
operating properly.
This warning light system monitors the airbag sensor
assembly, front airbag sensors, side and curtain shield airbag
sensor assemblies, curtain shield airbag sensor assemblies,
driver’s seat position sensor, driver’s seat belt buckle switch,
front passenger occupant classification system, “AIRBAG ON”
indicator light, “AIRBAG OFF” indicator light, front passenger’s
seat belt buckle switch, front seat belt pretensioner
assemblies, inflators, warning light, “RSCA OFF” indicator
light, interconnecting wiring and power sources. (For details,
see “Service reminder indicators and warning buzzers” on
page 51 for instructions.)

SECTION 3 – 1
341
STARTING AND DRIVING
Starting and driving
Three−way catalytic converters342
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Engine exhaust caution 343
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Before starting the engine 344
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Ignition switch 345
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Parking brake 347
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How to start the engine 348
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Automatic transmission 349
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Four−wheel drive system 356
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Rear view monitor system 358
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Cruise control 362
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Rear height control air suspension 366
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Electronic modulated suspension 371
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Active traction control system 372
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Vehicle stability control system 375
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Downhill assist control system 377
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Hill −start assist control 380
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Brake system 383
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Tire pressure warning system 387
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Brake pad wear limit indicators 394
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Limited −slip differential 395
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STARTING AND DRIVING
366
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 “HI” (high), “N”
(normal) and “LO” (low) modes with the height select
switch.
(a) Vehicle height modes
“N” (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. “HI”
(high) mode: The vehicle height is about 40 mm (1.6 in.)
higher at the rear than the “N” 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 “HI” mode, the “N” mode is automaticall\
y
selected.
CAUTION
The “HI” mode should be used for severe offroad
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.
“LO” (low) mode: The vehicle height is about 20 mm (0.8 in.)
lower at the rear than the “N” 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
368The height control indicator light indicates which mode is
selected. (See “(e) Height control indicator light” described
below.)

Selecting the “HI” mode
Push the height select switch on the “ ” side when the vehicle
speed is under about 30 km/h (19 mph).
To change the “N” mode to “HI”: Push the switch once.
To change the “LO” mode to “HI”: Push the switch twice. It
takes about 30 seconds until the “LO” mode changes to the “HI”
mode.
 Selecting the “N” mode
To change the “HI” mode to “N”: Push the height select
switch on the “
” side once.
To change the “LO” mode to “N”: Push the height select
switch on the “ ” side once.
 Selecting the “LO” mode
Push the height select switch on the “
” side while the vehicle
is stopped.
To change the “N” mode to “LO”: Push the switch once.
To change the “HI” mode to “LO”: 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.
NOTICE
 If the vehicle height is changed frequently when the
vehicle is heavily loaded, the compressor may
overheat causing the vehicle height adjustment
operation to stop.
 Before you lower the vehicle height with the height
select switch, check under the vehicle to make sure
nothing to damage 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 vehicl e equipped with
the rear height control air suspension becomes
slightly higher than the normal vehicle height. Take
sufficient care where the overhead height is
restricted.
 Do not select the “LO” mode in the bumpy roads. If
the underbody of the vehicle touches the rugged
road surface, the vehicle may be damaged.

STARTING AND DRIVING
369
(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 OFF”
switch. The height control “OFF” 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 “OFF” 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 OFF” switch, if the vehicle speed
exceeds 30 km/h (19 mph), the rear height control air
suspension automatically selects the “N” mode.
CAUTION
If you drive through deep water over about 700 mm (28
in.) in depth, put the vehicle height in the “HI” mode with
the height select switch and then turn off the rear height
control air suspension by pushing the “HEIGHT
CONTROL OFF” switch.
NOTICE
 When jacking up or installing tire chains, be sure to
turn off the rear height control air suspension with
the “HEIGHT CONTROL OFF” switch and stop the
engine. Otherwise, the vehicle height may change
because of the automatic leveling function resulting
in accident.
 If your vehicle must be towed, put the vehicle height
in the “N” mode and turn off the rear height control air
suspension. Otherwise, the vehicle height may
change because of the automatic leveling function
resulting in accident.
 If your vehicle gets ditched, turn off the rear height
control air suspension with the “HEIGHT CONTROL
OFF” switch. Otherwise, the vehicle height may
change because of the automatic leveling function
resulting in accident.

STARTING AND DRIVING
370
(e) Height control indicator lights
1Height control indicator lights
2Height control “OFF” 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 “N” mode to
“HI”:
1. The “N” mode indicator light goes off and the “HI” mode
indicator light blinks.
2. After the vehicle height control reaches the “HI” mode, the
“HI” 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 “OFF” indicator light:
When the ignition
switch is turned 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 OFF” switch,
the rear height control air suspension is turned off. The height
control “OFF” 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 “OFF” indicator light does not come on
when the ignition switch is turned on.
 The height control “OFF” indicator light blinks.

STARTING AND DRIVING
371
(f) Parking and stopping tips
If you immediately stop the engine to park the vehicle after
off−road driving, the vehicle height is lowered slightly as the
vehicle becomes cool. When parking, make sure there is
nothing that will be in contact with the underbody of the vehicle.
When you start the engine, the vehicle returns to the previous
height.
If you park the vehicle for a long time, the vehicle height may
be gradually lowered. When parking for a long time, make sure
there is nothing that will be in contact with the underbody of the
vehicle. When you start the engine, the vehicle returns to the
previous height.
If you stop the engine, the vehicle height may change in
accordance with the change in the temperature. When you
start the engine, the vehicle returns to the previous height.
(g) Rear height control failure warning
If there is a problem somewhere in the rear height control air
suspension, the “N” mode is automatically selected. If this
occurs, the height control “OFF” indicator light blinks and the
vehicle height control cannot be activated until the malfunction
is corrected. If this is the case, bring your vehicle to your Lexus
dealer as soon as possible and have it checked.
ELECTRONIC MODULATED SUSPENSION
This electronic modulated suspension adjusts the
damping effect on the shock absorbers with the control
switch. Select one of the 4 modes which is suited to the
driving conditions with the control switch to provide good
riding comfort and stability.
1For driving on a bumpy road
2For ordinary driving such as in the city traffic
3For moderate high speed driving
4For sporty type driving such as on winding mountain
roads and high speed driving
5Soft
6Firm

DRIVING TIPS
403
When driving offroad or in rugged terrain, do not
drive at excessive speeds, jump, make sharp turns,
strike objects, etc. This may cause loss of control or
vehicle rollover causing death or serious injury. You
are also risking expensive damage to your vehicle’s
suspension and chassis.
NOTICE
 If driving through water, such as when crossing
shallow streams, first check the depth of the water
and the bottom of the river bed for firmness. Drive
slowly and avoid deep water.
 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 can wash the grease from wheel bearings,
causing rusting and premature failure, and may also
enter the differentials, transmission and transfer
case, reducing the gear oil’s lubricating qualities.
 Sand and mud that has accumulated in brake drums
and around brake discs may affect braking ef ficiency
and may damage brake system components.
 Always perform a maintenance inspection after each
day of offroad driving that has taken you through
rough terrain, sand, mud, or water. For scheduled
maintenance information, refer to the “Owner’s
Manual Supplement/Scheduled Maintenance”.