engine overheat Lexus GX470 2003 How To Use This Manual / LEXUS 2003 GX470 OWNER'S MANUAL (OM60979U)

SWITCHES
37
SEAT HEATER SWITCHES
The seat heater has two dials; one marked “L” (for the
driver’s seat) and the other marked “R” (for the front
passenger’s seat). To turn the seat heaters on, turn the
dials forward. The indicator lights come on. To turn them
off, turn the dials backward until they stop. The indicator
lights go off.
You can adjust the heating temperature to 5 stages. To
increase the temperature, turn them forward. To decrease the
temperature, turn them backward.
The ignition key must be in the “ON” position.
CAUTION
Occupants must use caution when operating the seat
heater because they may experience minor burns even
at low temperatures. Use extra caution for;
 Babies, small children, elderly persons, sick persons
or handicapped persons
 Persons who have delicate skin
 Persons who are exhausted
 Persons who have taken alcohol or drugs which
induce sleep (sleeping drug, cold remedy, etc.).
To prevent the seat from overheating, do not use the
seat heater with a blanket, cushion, or other insulating
objects which cover the seat.
NOTICE
 Do not put unevenly weighted objects on the seat and
do not stick sharp objects (needles, nails, etc.) into
the seat.
 When cleaning the seats, do not use organic
substances (paint thinner, benzine, alcohol,
gasoline, etc.). They may damage the heater and seat
surface.
 To prevent the battery from being discharged, turn
the switches off when the engine is not running.

Finish
GAUGES, METERS AND SERVICE REMINDER INDICATORS
41
ENGINE COOLANT
TEMPERATURE GAUGE
 Normal range
The gauge indicates the engine coolant temperature when
the ignition switch is on. The engine operating
temperature will vary with changes in weather and engine
load.
If the needle points to the red zone or higher, stop your vehicle
and allow the engine to cool.
Your vehicle may overheat during severe operating conditions,
such as:
 Driving up a long hill on a hot day.
 Reducing speed or stopping after high speed driving.
 Idling for a long period with the air conditioning on in
stop−and−go traffic.
 Towing a trailer. It is not a malfunction even if the needle of the engine coolant
temperature gauge returns to “C” when the ignition switch is
turned to the “START”.
NOTICE

Do not remove the thermostat in the engine cooling
system as this may cause the engine to overheat. The
thermostat is designed to control the flow of coolant
to keep the temperature of the engine within the
specified operating range.
 Do not continue driving with an overheated engine.
See “If your vehicle overheats” on page 364.

STARTING AND DRIVING
297
THREEWAY CATALYTICCONVERTERS
Threeway catalytic converters are emission control
devices installed in the exhaust system.
The purpose is to reduce pollutants in the exhaust gas.
CAUTION
Keep people and combustible materials away from
the exhaust pipe while the engine is running. The
exhaust gas is very hot.
 Do not drive, idle or park your vehicle over anything
that might burn easily such as grass, leaves, paper or
rags.
NOTICE
A large amount of unburned gases flowing into the
threeway catalytic converter may cause it to overheat
and create a fire hazard. To prevent this and other
damage, observe the following precautions:
 Use only unleaded gasoline.
 Do not drive with an extremely low fuel level; running
out of fuel could cause the engine to misfire, creating
an excessive load on the threeway catalytic
converter.
 Do not allow the engine to run at idle speed for more
than 20 minutes.
 Avoid racing the engine.
 Do not pushstart or pullstart your vehicle.
 Do not turn off the ignition while the vehicle is
moving.
 Keep your engine in good running order.
Malfunctions in the engine electrical system, electric
ignition system or fuel system could cause an
extremely high threeway catalytic converter
temperature.
 If the engine becomes difficult to start or stalls
frequently, take your vehicle in for a checkup as
soon as possible. Remember, your Lexus dealer
knows your vehicle and its threeway catalytic
converter system best.

STARTING AND DRIVING
307
(c) Using the “3”, “2” and “L” positions
The “3”, “2” and “L” positions are used for strong engine\
braking
as described previously.
With the selector lever in “3”, “2” or “L”, you can start the vehicle
in motion as with the lever in “D”.
With the selector lever in “3” or “2”, the vehicle will start in firs\
t
gear and automatically shift to second gear.
With the selector lever in “L”, the transmission is engaged in
first gear.
NOTICE
 Be careful not to overrev the engine. Watch the
tachometer to keep engine rpm from going into the
red zone. The approximate maximum allowable
speed for each position is given below for your
reference:
Transmission Transfer
“L” “H”
“3” 53 km/h (33 mph) 136 km/h (85 mph)
“2” 36 km/h (22 mph) 93 km/h (58 mph)
“L” 21 km/h (13 mph) 54 km/h (33 mph)
 Do not continue hill climbing or hard towing for a long
time in the “3”, “2” or “L” position. This may cause
severe automatic transmission damage from
overheating. To prevent such damage, “4” position
should be used in hill climbing or hard towing.
(d) Backing up
 1 Brake pedal 2 “R” (Reverse) position
1. Bring the vehicle to a complete stop.
2. With the brake pedal held down with your foot, shift the
selector lever to the “R” position.
NOTICE
Never shift into reverse while the vehicle is moving.
When the shift lever is shifted into “R” position, the outside rear
view mirrors automatically down to help backing up. For
details, see page 116.

STARTING AND DRIVING
308
(e) Parking
 1 Brake pedal

2 Parking brake lever

3 “P” (Park) position
1. Bring the vehicle to a complete stop.
2. Apply the parking brake fully.
3. With the brake pedal held down with your foot, shift the
selector lever to the “P” position.
CAUTION
While the vehicle is moving, never attempt to move the
selector lever into “P” under any circumstances.
Serious mechanical damage and loss of vehicle control
may result.
(f) Good driving practice
 If the transmission repeatedly shifts up and down between
the fourth and overdrive gears when climbing a gentle slope,
shift the selector lever to the “4” position. Be sure to shift the
selector lever to the “D” position after climbing the slope.
 When towing a trailer, in order to maintain efficient engine
braking and electrical charging performance, do not use
overdrive.
CAUTION
Always keep your foot on the brake pedal while stopped
with the engine running. This prevents the vehicle from
creeping.
NOTICE
Always use the brake pedal or parking brake to hold the
vehicle on an upgrade. Do not attempt to hold the
vehicle using the accelerator pedal, as this can cause
the transmission to overheat.

STARTING AND DRIVING
317
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.

DRIVING TIPS
342
CAUTION
Before driving off, make sure the parking brake is
fully released and that the parking brake reminder
light is off.
 Do not leave your vehicle unattended while the
engine is running.
 Do not rest your foot on the brake pedal while driving.
It can cause dangerous overheating, needless wear,
and poor fuel economy.
 To drive down a long or steep hill, reduce your speed
and downshift. Remember, if you ride the brakes
excessively, they may overheat and not work
properly. See page 306.
 Be careful when accelerating, upshifting,
downshifting or braking on a slippery surface. The
abrupt change in engine speed, such as sudden
acceleration or engine braking, could cause the
vehicle to spin or skid.
 Do not drive in excess of the speed limit. Even if the
legal speed limit permits it, do not drive over 140 km/h
(85 mph) unless your vehicle has highspeed
capability tires. Driving over 140 km/h (85 mph) may
result in tire failure, loss of control and possible
injury. Be sure to consult a tire dealer to determine
whether the tires on your vehicle are highspeed
capability tires or not before driving at such speeds.
 Do not continue normal driving when the brakes are
wet. If they are wet, your vehicle will require a longer
stopping distance, and it may pull to one side when
the brakes are applied. Also, the parking brake will
not hold the vehicle securely.
 If you drive through deep water over about 500 mm
(20 in.) in depth, put the vehicle height in the HI (High)
mode with the active height select switch and then
turn off the active height control suspension by
pushing the height control switch. Drive your vehicle
at 30 km/h (19 mph) or lower speed.

DRIVING TIPS
355

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.