2003 Lexus GX470 brake

DRIVING TIPS
351
Matching trailer ball height to trailer coupler
height
No matter which class of tow hitch applies, for a safe trailer
hookup, the trailer ball setup on must be the proper height for
the coupler on the trailer.
32PY007
 1 Coupler2 Trailer ball
Brakes and safety chains
 Lexus recommends trailers with brakes that conform to
any applicable federal and state/provincial regulations.
 A safety chain must always be used between the towing
vehicle and the trailer. Leave sufficient slack in the
chain for turns. The chain should cross under the
trailer tongue to prevent the tongue from dropping to
the ground in case it becomes damaged or separated.
For correct safety chain procedures, consult your
Lexus dealer.
CAUTION
If the total trailer weight exceeds 453 kg (1000 lb.),
trailer brakes are required.
 Never tap into your vehicle’s hydraulic system as it
will lower its braking effectiveness.
 Never tow a trailer without using a safety chain
securely attached to both the trailer and the vehicle.
If damage occurs to the coupling unit or hitch ball,
there is possible danger of the trailer wandering over
into another lane.

DRIVING TIPS
352
Service connector for towing brake controller
Your vehicle is equipped with a service connector for the
towing brake controller as shown. Link the connector to the
towing brake controller via the sub wire harness stored in the
glove box. The detailed explanation of the sub wire harness
circuit is packed together with the sub wire harness. Be sure
to position the towing brake controller where it does not prevent
the driver from operating the pedal. Lexus recommends that
the sub wire harness be stored in the glove box when it is not
in use.
Tires
 Ensure that your vehicle’s tires are properly inflated. Adjust
the tire pressure to the recommended cold tire pressure
indicated below.
Tire pressure: 220 kPa (2.2 kgf/cm
2 or bar, 32 psi)
 The trailer tires should be inflated to the pressure
recommended by the trailer manufacturer in respect to the
total trailer weight.

DRIVING TIPS
355

Remember that when making a turn, the trailer wheels will
be closer than the vehicle wheels to the inside of the turn.
Therefore, compensate for this by making a larger than
normal turning radius with your vehicle.
 Crosswinds and rough roads will adversely affect handling
of your vehicle and trailer, causing sway. Pay attention to
the rear from time to time to prepare yourself for being
passed by large trucks or buses, which may cause your
vehicle and trailer to sway. If swaying happens, firmly grip
the steering wheel and reduce speed immediately but
gradually. Never increase speed. If it is necessary to
reduce speed, brake slowly. Steer straight ahead. If you
make no extreme correction with the steering or brakes,
your vehicle and trailer will stabilize.
 Be careful when passing other vehicles. Passing requires
considerable distance. After passing a vehicle, do not forget
the length of your trailer and be sure you have plenty of room
before changing lanes.
 In order to maintain efficient engine braking and electrical
charging performance, do not use overdrive. Transmission
must be “4” position.
 Because of the added load of the trailer, your vehicle’s
engine may overheat on hot days (at temperatures over
30C [85 F]) when going up a long or steep grade with a
trailer. If the engine coolant temperature gauge indicates
overheating, immediately turn off the air conditioning (if in
use), pull your vehicle off the road and stop in a safe spot.
See “If your vehicle overheats” on page 363. 
Always pl ace wheel blocks under both the vehicle and trailer
wheels when parking. Apply the parking brake firmly. Put
the transmission in “P”. Avoid parking on a slope with a
trailer, but if it cannot be avoided, do so only after performing
the following:
1. Apply the brakes and keep them applied.
2. Have someone place wheel blocks under both the vehicle
and trailer wheels.
3. When the wheel blocks are in place, release your brakes
slowly until the blocks absorb the load.
4. Apply the parking brake firmly.
5. Shift into “P” and turn off the engine.

DRIVING TIPS
356When restarting out after parking on a slope:
1. With the transmission in “P” position, start the engine. Be
sure to keep the brake pedal depressed.
2. Shift into the “3”, “2”, “L” or “R” 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 vehicletrailer 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 − 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 warmup idling. Once the engine is
running smoothly, begin driving − but gently. Remember,
however, that on cold winter days this may take a little
longer.
 Always keep the automatic transmission selector lever
in the “D” position when engine braking is not required.
Driving with the overdrive off will reduce the fuel economy.
(For details, see “Automatic transmission” on page 303.)
 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 overrevving. Use a gear position suitable
for the road on which you are traveling.

DRIVING TIPS
357

Avoid continuous speeding up and slowing down.
Stop−and−go driving wastes fuel.
 Avoid unnecessary stopping and braking. Maintain a
steady pace. Try to time the traf fic signals so you only need
to stop as little as possible or take advantage of through
streets to avoid traffic lights. Keep a proper distance from
other vehicles to avoid sudden braking. This will also
reduce wear on your brakes.
 Avoid heavy traffic or traffic jams whenever possible.
 Do not rest your foot on the brake pedal. This causes
premature wear, overheating and poor fuel economy.
 Maintain a moderate speed on highways. The faster you
drive, the greater the fuel consumption. By reducing your
speed, you will cut down on fuel consumption.
 Keep the front wheels in proper alignment. Avoid hitting
the curb and slow down on rough roads. Improper
alignment not only causes faster tire wear but also puts an
extra load on the engine, which, in turn, wastes fuel.
 Keep the bottom of your vehicle free from mud, etc. This
not only lessens weight but also helps prevent corrosion. 
Keep your vehicle tunedup and in top shape. A dirty air
cleaner, improper valve clearance, dirty plugs, dirty oil and
grease, brakes not adjusted, etc. all lower engine
performance and contribute to poor fuel economy. For
longer life of all parts and lower operating costs, keep all
maintenance work on schedule, and if you often drive under
severe conditions, see that your vehicle receives more
frequent maintenance. (For scheduled maintenance
information, please refer to the “Owner’s Manual
Supplement / Scheduled Maintenance”.)
CAUTION
Never turn off the engine to coast down hills. Your
power steering and brake booster will not function
without the engine running. Also, the emission control
system operates properly only when the engine is
running.

IN CASE OF AN EMERGENCY
359
IF YOUR ENGINE STALLS WHILEDRIVING
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 “ACC” or “LOCK”, and try starting
the engine again.
If the engine will not start, see “If your vehicle will not start”\
.
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
engine” on page 302 and that you have sufficient fuel. Since
your vehicle is equipped with the engine immobiliser 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 immobiliser system. Call your Lexus dealer.
See “Keys” on page 8.
If the engine is not turning over or is turning over too
slowly
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 starting” 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
“Foreword”.)

IN CASE OF AN EMERGENCY
363
IF YOU CANNOT INCREASE THEENGINE 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 “ACC” or “LOCK” position.
CAUTION
Be especially careful to prevent erroneous pedal
operation.
IF YOUR VEHICLE OVERHEATS
If your engine coolant temperature gauge indicates
overheating, if you experience a loss of power, or if you
hear a loud knocking or pinging noise, the engine has
probably overheated.
When the engine overheats
Pull safely off the road, stop the vehicle and turn on your
emergency flashers. Put the transmission in “P” and apply the
parking brake.
A: If steam is coming from your engine:
Turn off the engine. Leave the hood closed until there is no sign
of steam or coolant. Your engine could have been seriously
damaged already. Call your Lexus dealer for assistance.
CAUTION
To help avoid personal injury, keep the hood closed until
there is no steam. Escaping steam or coolant is sign of
very high pressure.

IN CASE OF AN EMERGENCY
364B: If no steam is coming from your engine:
Leave the engine running and turn off the air conditioning.
Check the following.

Is the cooling fan operating?
 Is the coolant in the acceptable range?
 Is the engine drive belt O.K.?
CAUTION
When the engine is running, keep hands and clothing
away from the moving fan and engine drive belt.
 Do not attempt to remove the radiator cap when the
engine and radiator are hot. Serious injury could
result from scalding hot fluid and steam blown out
under pressure.
If the cooling fan is not operating or the coolant is not in the
acceptable range, turn off the engine and call your Lexus
dealer.
If both conditions are O.K., after the engine coolant
temperature has cooled to normal, continue driving your
vehicle.
If the engine coolant temperature does not cool down, or your
vehicle overheats again, have it checked as soon as possible
by your Lexus dealer.
IF YOU HAVE A FLAT TIRE
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place − well away from the
traffic. A void stopping on the center divider of a highway. Park
on a level spot with firm ground.
2. Stop the engine and turn on your emergency flashers.
3. Firmly set the parking brake and put the transmission in “P”.
4. Have everyone get out of the vehicle on the side away from
traffic.
5. Read the following instructions thoroughly.
CAUTION
When jacking, be sure to observe the following to
reduce the possibility of personal injury:
 Turn off the active height control suspension by
pushing the active height control switch.
 Follow jacking instructions.
 Do not put any part of your body under a vehicle
supported by a jack. Personal injury may occur.
 Do not start or run the engine while your vehicle is
supported by the jack.
 Stop the vehicle on a level firm ground, firmly set the
parking brake and put the transmission in “P”. Block
the wheel diagonally opposite to the one being
changed if necessary.