2004 Lexus GX470 suspension

SECTION 3 ± 1
366
STARTING AND DRIVING
Starting and driving
Three-way catalytic converters367 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine exhaust caution370 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Before starting the engine372 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition switch with steering lock372 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking brake374 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to start the engine374 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic transmission376 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Four-wheel drive system384 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear view monitor system388 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cruise control392 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear height control air suspension395 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronic modulated suspension402 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Active traction control system403 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vehicle stability control system405 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Downhill assist control system408 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hill-start assist control system411 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake system413 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tire pressure warning system417 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake pad wear limit indicators426 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Limited-slip differential427 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

STARTING AND DRIVING
395
REAR HEIGHT CONTROL AIR
SUSPENSION
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
397 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
398
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 vehicle 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 LOº mode in the bumpy roads. If
the underbody of the vehicle touches the rugged
road surface, the vehicle may be damaged.

STARTING AND DRIVING
399
(d) Turning off the rear height control air
suspension
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
400
NOTICE
When jacking up or installing tire chains, be sure to
turn off the rear height control air suspension with
the HEIGHT CONTROL OFFº 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 Nº 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
OFFº switch. Otherwise, the vehicle height may
change because of the automatic leveling function
resulting in accident.

STARTING AND DRIVING
401
(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 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 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.

STARTING AND DRIVING
402
(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 Nº mode is automatically selected. If this
occurs, the height control OFFº 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
We recommend you to select the mode 2
for ordinary
driving. The damping effect will be changed automatically to
provide good riding comfort.