2004 Lexus GX470 check engine

STARTING AND DRIVING
402
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 lightº on page 60.
Drum-in-disc 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
413
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 efficiency
and may damage brake system components.
Always perform a maintenance inspection after each
day of off-road driving that has taken you through
rough terrain, sand, mud, or water. For scheduled
maintenance information, refer to the Owner's
Manual Supplement/Scheduled Maintenanceº.

DRIVING TIPS
414
WINTER DRIVING TIPS
Make sure your coolant is properly protected against
freezing.
Only use Toyota Super Long Life Coolantº or similar high
quality ethylene glycol based non- silicate, non- amine,
non- nitrite, and non- borate coolant with long- life hybrid
organic acid technology.
See Checking the engine coolant levelº on page 519 for
details of coolant type selection.
Toyota Super Long Life Coolantº is pre- mixed with 50%
coolant and 50% deionized water. This coolant provides
protection down to about -35C (-31F).
NOTICE
Do not use plain water alone.
Check the condition of the battery and cables.
Cold temperatures reduce the capacity of any battery, so it
must be in top shape to provide enough power for winter
starting. Page 562 tells you how to visually inspect the battery.
Your Lexus dealer and most service stations will be pleased to
check the battery charge level.Make sure the engine oil viscosity is suitable for the cold
weather.
See page 518 for recommended viscosity. Leaving a heavy
summer oil in your vehicle during winter months may cause
harder starting. If you are not sure about which oil to use, call
your Lexus dealer Ð they will be pleased to help.
Check the electronic ignition system for loose
connections or obvious damage.
Keep the door locks from freezing.
Squirt lock de-icer or glycerine into the locks to keep them from
freezing.

DRIVING TIPS
415 Use a washer fluid containing an antifreeze solution.
This product is available at your Lexus dealer and most auto
parts stores. Follow the manufacturer's directions for how
much to mix with water.
NOTICE
Do not use engine antifreeze or any other substitute
because it may damage your vehicle's paint.
Do not use your parking brake when there is a possibility
it could freeze.
When parking, put the transmission into Pº and block the front
wheels. Do not use the parking brake, or snow or water
accumulated in and around the parking brake mechanism may
freeze the parking brake, making it hard to release.Keep ice and snow from accumulating under the fenders.
Ice and snow built up under your fenders can make steering
difficult. During bad winter driving, stop and check under the
fenders occasionally.
Depending on where you are driving, we recommend you
carry some emergency equipment.
Some of the things you might put in the vehicle are tire chains,
window scraper, bag of sand or salt, flares, small shovel,
jumper cables, etc.

DRIVING TIPS
426
Trailer lights
Your vehicle is equipped with a wire harness stored in the rear
end underbody. Use either of them to connect and operate the
trailer lights. However, the trailer lights must comply with
federal, state/provincial and local regulations. See your local
recreational vehicle dealer or rental agency for the correct type
of wiring and relays for your trailer. Check for correct operation
of the turn signals and stop lights each time you hitch up. Direct
splicing may damage your vehicle's electrical system and
cause a malfunction of your lights.
Break-in schedule
Lexus recommends that you do not tow a trailer with a new
vehicle or a vehicle with any new power train component
(engine, transmission, differential, wheel bearing, etc.) for the
first 800 km (500 miles) of driving.
Maintenance
If you tow a trailer, your vehicle will require more frequent
maintenance due to the additional load. For this
information, please refer to the scheduled maintenance
information in the Owner's Manual Supplement/Scheduled
Maintenanceº.
Retighten all fixing bolts of the towing ball and bracket after
approximately 1000 km (600 miles) of trailer driving.
Connecting a trailer
Stop your vehicle and a trailer in line and perform the following:
1. Put the rear height control air suspension in the LOº (low)
mode. Turn the ignition switch off or push the HEIGHT
CONTROL OFFº switch to turn off the rear height control air
suspension.
2. Connect a trailer.
3. Turn the ignition switch on or push the HEIGHT CONTROL
OFFº switch to turn on the rear height control air suspension.
Select the Nº (normal) mode with the height select switch.
Disconnecting a trailer
Stop your vehicle and a trailer in line and perform the following:
1. Put the rear height control air suspension in the LOº (low)
mode. (Make sure the vehicle height is in the LOº (low) mode
by pushing the height select switch on the º side.)
2. Turn the ignition switch off or push the HEIGHT CONTROL
OFFº switch to turn off the rear height control air suspension.
3. Set the supporting leg of a trailer on the ground and raise the
hitch by 100 mm (4 in.).
4. Turn the ignition switch on or push the HEIGHT CONTROL
OFFº switch to turn on the rear height control air suspension.
5. Wait for about 20 seconds until the rear vehicle height is
lowered by the automatic leveling function.
6. Make sure the hitch is disconnected. If not, raise the hitch
higher and repeat steps 2 through 5.

DRIVING TIPS
429 When restarting out after parking on a slope:
1. With the transmission in Pº position, start the engine. Be
sure to keep the brake pedal depressed.
2. Shift into the 3º, 2º, Lº or Rº position.
3. Release the parking brake and brake pedal and slowly pull
or back away from the wheel blocks. Stop and apply your
brakes.
4. Have someone retrieve the blocks.
CAUTION
Do not exceed 72 km/h (45 mph) or the posted towing
speed limit, whichever is lower. Because instability
(swaying) of a towing vehicle-trailer combination
usually increases as the speed increases, exceeding
72 km/h (45 mph) may cause loss of control.
Slow down and downshift before descending steep
or long downhill grades. Do not make sudden
downshifts.
Avoid holding the brake pedal down too long or too
frequently. This could cause the brakes to overheat
and result in reduced braking efficiency.
HOW TO SAVE FUEL AND MAKE
YOUR VEHICLE LAST LONGER
Improving fuel economy is easy Ð just take it easy. It will help
make your vehicle last longer, too. Here are some specific tips
on how to save money on both fuel and repairs:
Keep your tires inflated at the correct pressure. Check
the pressure every two weeks, or at least once a month.
Underinflation causes tire wear and wastes fuel.
Do not carry unneeded weight in your vehicle. Excess
weight puts a heavier load on the engine, causing greater
fuel consumption.
Avoid lengthy warm-up idling. Once the engine is
running smoothly, begin driving Ð but gently. Remember,
however, that on cold winter days this may take a little
longer.
Always keep the automatic transmission selector lever
in the Dº position when engine braking is not required.
Driving with the overdrive off will reduce the fuel economy.
(For details, see Automatic transmissionº on page 365.)
Accelerate slowly and smoothly. Avoid jackrabbit starts.
Avoid long engine idling. If you have a long wait and you
are not in traffic, it is better to turn off the engine and start
again later.
Avoid engine over-revving. Use a gear position suitable
for the road on which you are traveling.

IN CASE OF AN EMERGENCY
438
IF YOUR ENGINE STALLS WHILE
DRIVING
If your engine stalls while driving...
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place.
2. Turn on your emergency flashers.
3. Turn the ignition key to ACCº or LOCKº, and try starting the
engine again.
If the engine will not start, see If your vehicle will not startº.
CAUTION
If the engine is not running, the power assist for the
brakes and steering will not work, so steering and
braking will be much harder than usual.
IF YOUR VEHICLE WILL NOT
START
(a) Simple checks
Before making these checks, make sure you have followed the
correct starting procedure instructions in How to start the
engineº on page 363 and that you have sufficient fuel. Since
your vehicle is equipped with the engine immobilizer system,
also check whether the other keys will start the engine. If they
work, your key may be broken. Have the key checked at your
Lexus dealer. If none of your keys work, there may be a
malfunction in the immobilizer system. Call your Lexus dealer.
See Keysº on page 8.
If the engine is not turning over or is turning over too
slowly Ð
1. Check that the battery terminals are tight and clean.
2. If the battery terminals are O.K., switch on the interior light.
3. If the light is out, dim or goes out when the starter is cranked,
the battery is discharged. You may try jump starting. See (c)
Jump startingº for further instruction.
If the light is O.K., but the engine still will not start, it needs
adjustment or repair. Call a Lexus dealer, Roadside
Assistance or Customer Service Assistance. (See
Forewordº.)

IN CASE OF AN EMERGENCY
442
CAUTION
When making the connections, to avoid serious injury,
do not lean over the battery or accidentally let the
jumper cables or clamps touch anything except the
correct battery terminals or the ground.
5. Start your engine in the normal way. After starting, run it at
about 2000 rpm for several minutes with the accelerator pedal
lightly depressed.
6. Carefully disconnect the cables in the exact reverse order:
the negative cable and then the positive cable.
7. Carefully dispose of the battery cover cloths which may now
contain sulfuric acid.
8. If removed, replace all the battery vent plugs.
If the cause of your battery discharging is not apparent (for
example, lights left on), you should have it checked at your
Lexus dealer.
IF YOU CANNOT INCREASE THE
ENGINE SPEED
If the engine speed does not increase with the accelerator
pedal depressed down, there may be a problem somewhere
in your electronic throttle control system.
At this time, vibration may occur. However, if you depress the
accelerator pedal more firmly and slowly, you can drive your
vehicle at low speeds. Have your vehicle checked by your
Lexus dealer as soon as possible.
Even if the abnormality of the electronic throttle control system
is corrected during low speed driving, the system may not be
recovered until the engine is stopped and the ignition key is
turned to ACCº or LOCKº position.
CAUTION
Be especially careful to prevent erroneous pedal
operation.