2003 Lexus GX470 check engine

STARTING AND DRIVING
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HOW TO START THE ENGINE
Cranking hold function
Once you turn the ignition key to “START” position and release
it, the cranking hold function continues to crank the engine in
“ON” position until it starts.
The function stops cranking the engine after about 25 seconds
maximum if the engine has not started yet. When you crank
the engine again, wait a few seconds and restart it.
If you hold the key in “START” position, the function will keep
cranking for about 30 seconds maximum.
Before cranking
1. Apply the parking brake firmly.
2. Turn off unnecessary lights and accessories.
3. Put the selector lever in “P”. If you need to restart the engine
while the vehicle is moving, put the selector lever in “N”. A
starter safety device will prevent the starter from operating if
the selector lever is in any drive position.
4. Depress the brake pedal and hold it to the floor until driving
off.
Starting the engine
Before starting the engine, be sure to follow the instructions in
“Before cranking”.
Normal starting procedure
The multiport fuel injection system/sequential multiport fuel
injection system in your engine automatically controls the
proper air −fuel mixture for starting. You can start a cold or hot
engine as follows:
1. With your foot off the acce lerator pedal, turn the ignition key
to “START” position, then release it.
2. After the engine runs for about 10 seconds, you are ready
to drive.
If the weather is below freezing, let the engine warm up for a
few minutes before driving. Do not leave the vehicle while the
engine is warming up.
If the engine stalls ...
Simply restart it , using the correct procedure given in normal
starting.
If the engine will not start ...
See “If your vehicle will not start” on page 359.
NOTICE
 Do not race a cold engine.
 If the engine becomes difficult to start or stalls
frequently, have the engine checked immediately.

STARTING AND DRIVING
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The 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 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 “LO” mode in the bumpy roads. If
the underbody of the vehicle touches the rugged
road surface, the vehicle may be damaged.

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(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.
1 For driving on a bumpy road
2 For ordinary driving such as in the city traffic
3 For moderate high speed driving
4 For sporty type driving such as on winding mountain
roads and high speed driving
5 Soft
6 Firm
We recommend you to select the mode
2
for ordinary
driving. The damping effect will be changed automatically to
provide good riding comfort.

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 Slip indicator light
Leave the system on during the ordinary driving so that it
can operate when needed.
You may hear a sound in the engine compartment for a few
seconds when the engine is started or just after the vehicle
begins to move. This means that the active traction control
system is in the self−check mode, but does not indicate a
malfunction.
When the active traction control system is operating, the
following conditions occur:
 The system controls the spinning of the 4 wheels. At this
time, the slip indicator light blinks.
 You may feel vibration or noise in your vehicle, caused by
operation of the brakes. This indicates the system is
functioning properly. The slip indicator light comes on for a few seconds when the
ignition key is turned to “ON”. If the indicator light does not
come on when the ignition is turned on, contact your Lexus
dealer.
“VSC TRAC” warning light
This light warns that there is a problem somewhere in the
following.

Active traction control system
 Vehicle skid control system
 Downhill assist control system
 Hill− start assist control system
When the system is normal and the ignition key is turned to
“ON”, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the “ON”
position.

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Depressing the brake pedal repeatedly may turn on the light.
It is normal if it goes out after a few seconds.
The brake actuator temperature increases during continuous
operation of
the above mentioned systems such as on slippery
roads. If the brake actuator temperature becomes too high
while any of the systems is operating, a buzzer will start to
sound intermittently to indicate that the active traction control
system can no longer operate. In this case, immediately stop
your vehicle at a safe place.
If the system continues to operate, the buzzer sound changes
from intermittent to continuous. (The continuous buzzer
sounds for about 3 seconds.) At the time, the “VSC TRAC”
warning light will come on and the active traction control
system temporarily stops operating in order to protect the
brake actuator. (Although the active traction control system
does not operate, there is no problem to continue your driving.)
The system will be automatically restored after a short time and
the “VSC TRAC” warning light goes out.
If the light comes on while driving, the active traction control
system does not work. However, as normal braking operates
when being applied, there is no problem to continue your
driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to “ON”.
 The warning light remains on after the ignition key is turned
to “ON”.
 The warning light comes on while driving.
VEHICLE SKID CONTROL SYSTEM
The vehicle skid control system helps provide integrated
control of the systems such as antilock brake system,
traction control, engine control, etc. This system
automatically controls t he output of the brakes or engine
to help prevent the vehicle from skidding when cornering
on a slippery road surface or operating steering wheel
abruptly.
The vehicle skid control activates when the vehicle speed is
more than following speed:
Four− wheel drive control lever in “H” 15 km/h (9 mph) . . .
Four−wheel drive control lever in “L” 30 km/h (19 mph) . . .
You may hear a sound in the engine compartment for a few
seconds when the engine is started or just after the vehicle
begins to move. This means that the system is in the
self−check mode, but does not indicate a malfunction.
CAUTION
 Do not rely excessively on the vehicle skid control
system. Even if the vehicle skid control system is
operating, you must always drive carefully and
attentively to avoid serious injury. Reckless driving
will result in an unexpected accident. If the slip
indicator light blinks and an alarm sounds, special
care should be taken while driving.

STARTING AND DRIVING
332You may hear a small sound in the engine compartment after
the engine is started or the brake pedal is depressed
repeatedly. This is a pump pulsating sound of the brake
system, and it is not a malfunction.
CAUTION

Do not pump the brake pedal if the engine stalls.
Each push on the pedal uses up your brake fluid
pressure reserve.
 Even if the power assist is completely lost, the brakes
will still work. But you will have to push the pedal
hard, much harder than normal. And your braking
distance will be longer.
Antilock brake system
The antilock brake system is designed to automatically
help prevent lockup of the wheels during a sudden brake
or braking on slippery road surfaces. This assists in
providing directional stability and steering performance
of the vehicle under these circumstances.
Effective way to press the ABS brake pedal: When the
anti−lock brake system function is in action, you may feel the
brake pedal pulsating and hear a noise. In this situation, to
let the anti−lock brake system work for you, just hold the
brake pedal down more firmly. Do not pump the brake in a
panic stop. This will result in reduced braking performance.
The anti−lock brake system becomes operative after the
vehicle has accelerated to a speed in excess of approximately
10 km/h (6 mph). It stops operating when the vehicle
decelerates to a speed below approximately 5 km/h (3 mph).
Depressing the brake pedal on slippery road surfaces such as
on the manhole cover, the steel plate under the construction,
joints in the bridge, etc. on a rainy day tends to activate the
anti−lock brake system.
You may hear a click or motor sound in the engine
compartment for a few seconds when the engine is started or
just after the vehicle begins to move. This means that the
anti−lock brake system is in the self −check mode, and does not
indicate a malfunction.
When the antilock brake system is activated, the
following conditions may occur. They do not indicate a
malfunction of the system:
 You may hear the anti −lock brake system operating and feel
the brake pedal pulsating and the vibrations of the vehicle
body and steering wheel. You may also hear the motor
sound in the engine compartment even after the vehicle is
stopped.
 At the end of the anti−lock brake system activation, the
brake pedal may move a little to the forward.

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Brake assist system
When you slam the brakes on, the brake assist system
judges as an emergency stop and provides more powerful
braking for a driver who cannot hold down the brake pedal
firmly.
When you slam the brakes on, more powerful braking will be
applied. At this time, you may hear a sound in the engine
compartment and feel the vibrations of the brake pedal. This
does not indicate a malfunction.
The brake assist system becomes operative after the vehicle
has accelerated to a speed in excess of approximately 10 km/h
(6 mph). It stops operating when the vehicle decelerates to a
speed below approximately 5 km/h (3 mph).
The brake assist system may not work for about 60 seconds
after the engine is started.
For an explanation of this system’s warning light, see “ABS
warning light” on page 48.
Drumindisc type parking brake system
Your vehicle has a drum−in−disc type parking brake system.
This type of brake system needs bedding −down of the brake
shoes periodically or whenever the parking brake shoes and/or
drums are replaced.
Have your Lexus dealer perform the bedding −down.
BRAKE PAD WEAR LIMIT
INDICATORS
The brake pad wear limit indicators on your disc brakes
give a warning noise when the brake pads are worn to the
extent that replacement is required.
If you hear a squealing or scraping noise while driving, have the
brake pads checked and replaced by your Lexus dealer as
soon as possible. Expensive rotor damage can result if the
pads are not replaced when needed.

DRIVING TIPS
344
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”.