brakes TOYOTA PRIUS 2003 1.G Owners Manual

8
Toyota hybrid system combines the
gasoline engine and the electric motor
power to improve the fuel economy
largely and minimize the emissions as
well as to provide higher power perfor-
mance than the ordinary gasolinepow-
ered vehicles.
Depending on the driving condition, the
vehicle runs on the best combination of;
Gasoline engine power
Electric motor power generated by
the gasoline engine
Electric motor power of the hybrid
vehicle battery
Furthermore, the energy is effectively used
in the following ways:
When stopping the vehicle, the gaso-
line engine is automatically stopped.
When decreasing the speed by apply-
ing the brakes, electricity converted
from the turning force of the wheels is
stored in the hybrid vehicle battery.
(This is called regenerative brake.) Since the battery is charged by the
gasoline engine as needed, it does not
require charging from the outside like
an electric vehicle.
In this way, greatly improved fuel economy
and reduced emissions are attained.
If you do not use the vehicle for a long
time (2 weeks or more),
the hybrid ve-
hicle battery and auxiliary battery will dis-
charge and their condition is liable to de-
cline. Therefore, in order to make up for
discharging, charge them once in every 2
weeks for about 30 minutes by starting
the hybrid system with all electrical com-
ponents turned off. Basic operations are described below. Be-
sides, Toyota hybrid system performs vari-
ous controls depending on the operating
condition, such as at the time of hybrid
system starting, at the time of charging
should be required, at the time of the air
conditioning is in use, etc.
6.Toyota hybrid system
7.Toyota hybrid system
operating condition

10
12p019a
Storing electric power
When decreasing speed or applying the
brakes, the turning force of the wheels
makes the electric motor operate as a
generator and additional electricity is
stored in the hybrid vehicle battery (regen-
erative brake).
12p020a
Not in use
When stopping, the gasoline engine auto-
matically shuts off.
12p030
Charging hybrid vehicle battery
When the hybrid vehicle battery power is
insufficient, the gasoline engine charges
the hybrid vehicle battery. The system al-
ways supplies electricity at a constant lev-
el.

95
(a) Brake System Warning Light andBuzzer
This light comes on in the following cases
when the ignition key is in the “ON” posi-
tion.
When the parking brake is applied...
This light comes on for a few seconds
when the ignition key is turned to the
“ON” position even after the parking brake
is released.
When the brake fluid level is low...
CAUTION
It is dangerous to continue driving
normally when the brake fluid level is
low.
When the regenerative brake system
is fails...
When the hydraulic brake booster
fails...
If the hydraulic booster causes a problem
resulting in poor braking performance, the
warning light comes on and buzzer sounds
continuously. Have your vehicle checked at your
Toyota dealer in the following cases:
The light does not come on even if the
parking brake is applied when the igni-
tion key is in the “ON” position.
The light does not come on even if the
ignition key is turned on with the park-
ing brake released.
A warning light turning on briefly during
operation does not indicate a problem.
CAUTION
If any of the following conditions oc-
curs, immediately stop your vehicle at
a safe place and contact your Toyota
dealer.
The light does not turn off even
after the parking brake is released
while the hybrid system is running.
The warning buzzer comes on to-
gether with the warning light.
In either case, this can indicate that
the brakes may not work properly and
your stopping distance will become
longer. Depress the brake pedal firmly
and bring the vehicle to an immediate
stop.
The brake system warning light re-
mains on together with the “ABS”
warning light.
In this case, not only the antilock
brake system will fail but also the
vehicle will become extremely unsta-
ble during braking.
Any of the following conditions may oc-
cur, but do not indicate the malfunc-
tion:
The light may stay on for about 60
seconds after the ignition key is turned
to the “ON” position. It is normal if it
turns off after a while.
Depressing the brake pedal repeatedly
may turn on the warning light and
buzzer. It is normal if the light turns off
and the buzzer stops sounding after a
few seconds.
You may hear a small sound in the
engine compartment after the hybrid
system is started or the brake p edal is
depressed repeatedly. This is a pump
pulsating sound of the brake system,
and it is not a malfunction.

157
HYDRAULIC BRAKE
This brake system has 2 independent hy-
draulic circuits. If either circuit should fail,
the other will still work. However, the ped-
al will be harder to press, and your stop-
ping distance will be longer. Also, the
brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a
single brake system. Have your
brakes fixed immediately.
BRAKE BOOSTER
The brake booster uses brake fluid pres-
surized by the pump to powerassist the
brakes. If the brake booster fails during
driving, the brake system warning light
comes on and buzzer sounds continuous-
ly. In this case, the brakes may not work
properly. If they do not work well, depress
the brake pedal firmly. If the brake system
warning light comes on, immediately stop
your vehicle and contact your Toyota deal-
er.The brake system warning light may stay
on for about 60 seconds after the ignition
key is turned to the “ON” position. It is
normal if the light turns off after a while.
Depressing the brake pedal repeatedly
may turn on the brake system warning
light and buzzer. It is normal if the light
turns off and the buzzer stops sounding
after a few seconds.
You may hear a small sound in the engine
compartment after the hybrid system 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
hybrid system is not operating.
Each push on the pedal uses up
your reserved brake fluid pressure.
Even if the power assist is com-
pletely lost, the brakes will still
work. But you will have to push the
pedal hard, much harder than nor-
mal. 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 braking or
braking on slippery road surfaces. This
assists in providing directional stab
ility
and steering performance of the vehicle
under these circumstances.
Effective way to press the ABS brake
pedal: When the antilock brake system
function is in action, you may feel the
brake pedal pulsating and hear a noise.
In this situation, to let the antilock
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 perfor-
mance.
The antilock brake system becomes op-
erative 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).

160
30p003
The brake pad wear limit indicators on
your disc brakes give a warning noise
when the brake pads are worn to where
replacement is required.
If you hear a squealing or scraping noise
while driving, have the brake pads
checked and replaced by your Toyota
dealer as soon as possible. Expensive ro-
tor damage can result if the pads are not
replaced when necessary.When stowing luggage or cargo in the
vehicle, observe the following:
Put luggage or cargo in the trunk when
at all possible. Be sure all items are
secured in place.
Be careful to keep the vehicle bal-
anced. Locating the weight as far for-
ward as possible helps maintain bal-
ance.
For better fuel economy, do not carry
unneeded weight.
CAUTION
Do not place anything on the pack-
age tray behind the rear seatback
or luggage cover. Such items may
be thrown about and possibly injure
people in the vehicle during sudden
braking or an accident.
Do not drive with objects left on
top of the instrument panel. They
may interfere with the driver’s field
of view. Or they may move during
sharp vehicle acceleration or turn-
ing, and impair the driver’s control
of the vehicle. In an accident they
may injure the vehicle occupants.
NOTICE
Do not load the vehicle beyond the
vehicle capacity weight given in Sec-
tion 9.
114.Brake pad wear limit
indicators
115.Luggage stowage
precautions

167
When the ignition switch is turned to on
or off, you may hear a sound coming from
the hybrid vehicle battery in the trunk.
However, this does not indicate any
trouble.
NOTICE
The “READY” light does not come on
when the selector lever is put in a
position other than “P”. Depress the
brake pedal and put the selector lever
in “P” and turn the ignition switch to
“START” again.
If there is a problem somewhere in the
hybrid system, the hybrid system malfunc-
tion warning light will come on in place of
the “READY” light. If this happens, contact
Toyota dealer.
NOTICE
When you start the hybrid system at
a lowered outside temperature, it may
take longer before the blinking
“READY” light changes to stay on.
Always slow down in gusty crosswinds.
This will allow you much better control.
Drive slowly onto curbs and, if pos-
sible, at a right angle. Avoid driving
onto high, sharpedged objects and
other road hazards. Failure to do so
can lead to severe tire damage result-
ing in tire bursts.
Drive slowly when passing over bumps
or travelling on a bumpy road. Other-
wise, the impact could cause severe
damage to the tires and/or wheels.
When parking on a hill, turn the front
wheels until they touch the curb so
that the vehicle will not roll. Apply the
parking brake, and put the selector le-
ver into “P”. If necessary, block the
wheels.
Washing your vehicle or driving through
deep water may get the brakes wet. To
see whether they are wet, check that
there is no traffic near you, and then
press the pedal lightly. If you do not
feel a normal braking force, the brakes
are probably wet. To dry them, drive
the vehicle cautiously while lightly
pressing the brake pedal with the park-
ing brake pulled. If they still do not
work safely, pull to the side of the road
and call a Toyota dealer for assistance.
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 unat-
tended with the “READY” light on.
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.
Be careful when accelerating or
braking on a slippery surface. Sud-
den acceleration or engine braking,
could cause the vehicle to spin or
skid.
Tips for driving in various
conditions123.

168
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 lon-
ger stopping distance, and it may
pull to one side when the brakes
are applied. Also, the parking brake
will not hold the vehicle securely.
Make sure you have a proper freeze
protection of coolant.
Your coolant must contain ethyleneglycol
type coolant for a proper corrosion
protection of aluminum components. Use
“Toyota Genuine Long Life Coolant” or
equivalent.
See 217 page in Section 82 for details
about coolant type selection.
NOTICE
Do not use alcohol type antifreeze or
plain water alone.
When it is extremely cold, we recommend
to use 60% solution for your Toyota, to
provide protection down to about 50°C
(58 °F). Do not use more than 70% solu-
tion for better coolant performance.
Check the condition of the auxiliary
battery and cables.
Cold temperatures reduce the capacity of
any auxiliary battery, so it must be in top
shape to provide enough power for winter
starting. Section 83 tells you how to
visually inspect the auxiliary battery. Your
Toyota dealer will be pleased to check the
level of charge. Make sure the engine oil viscosity is
suitable for the cold weather.
See 215 page in Section 82 for recom-
mended viscosity. Leaving a heavy sum-
mer oil in your vehicle during winter
months may cause harder starting. If you
are not sure about which oil to use, call
your Toyota dealer—he will be pleased to
help.
Keep the door locks from freezing.
Squirt lock deicer or glycerine into the
locks to keep them from freezing.
Use a washer fluid containing an anti
freeze solution.
This product is available at your Toyota
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 as washer fluid be-
cause it may damage your vehicle’s
paint.
Winter driving tips124.

170
Improving fuel economy is easyjust 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 cor-
rect pressure. Underinflation causes
tire wear and wastes fuel. See page
221 in Section 82 for instructions.
Do not carry unneeded weight in
your vehicle. Excess weight puts a
heavier load on the engine, causing
greater fuel consumption.
Accelerate slowly and smoothly.
Avoid jackrabbit starts.
Avoid continuous speeding up and
slowing down. Stopandgo driving
wastes power.
Avoid unnecessary stopping and
braking. Maintain a steady pace. Try
to time the traffic signals so you only
need to stop as little as possible or
take advantage of through streets to
avoid traffic lights. Keep a proper dis-
tance from other vehicles to avoid sud-
den braking. This will also reduce wear
on your brakes.
Avoid heavy traffic or traffic jams
whenever possible.
Do not rest your foot on brake ped-
al. This causes premature wear, over-
heating and poor fuel economy.
Maintain a moderate speed on high-
ways. The faster you drive, the greater
the fuel consumption. By reducing your
speed, you will cut down on fuel con-
sumption.
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 corro-
sion.
Keep your vehicle tunedup and in
top shape . A dirty air cleaner, improp-
er valve clearance, dirty plugs, dirty oil
and grease, brakes not adjusted, etc.
all lower engine performance and con-
tribute 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 ve-
hicle receives more frequent mainte-
nance.
CAUTION
Never turn off the hybrid system to
coast down hills. Your power steering
and brake booster will not function
without the hybrid system running.
Also, the emission control system op-
erates properly only when the hybrid
system is running.
How to save fuel and make
your vehicle last longer,
too127.

176
If your hybrid system 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 switch to ”OFF” posi- tion, and try starting the hybrid system
again.
If the hybrid system will not start, see “If
your vehicle will not start” on page 172.
CAUTION
If the hybrid system is not operating,
the power assist for the brakes and
steering will not work so steering and
braking will be much harder than usu-
al.
If your high coolant temperature warn-
ing light comes on, if you experience a
loss of power, or if you hear a loud
knocking or pinging noise, the hybrid
system has probably overheated. You
should follow this procedure... 1. Pull safely off the road, stop the ve- hicle and turn on your emergency
flashers. Put the transmission in “P”
and apply the parking brake. Turn off
the air conditioning if it is being used.
2. If coolant or steam is boiling out of the radiator or reservoir, stop the hybrid
system. Wait until the steam subsides
before opening the hood. If there is no
coolant boiling over or steam, leave the
hybrid system running and make sure
the electric cooling fan is operating. If
it is not, turn the ignition off.
CAUTION
To help avoid personal injury, keep
the hood closed until there is no
steam. Escaping steam or coolant is
a sign of very high pressure.
3. Look for obvious coolant leaks from theradiator, hoses, and under the vehicle.
However, note that water draining from
the air conditioning is normal if it has
been used.
CAUTION
When the hybrid system is running,
keep hands and clothing away from
the moving fan and engine drive
belts.
4. If the coolant is leaking, stop the hy-brid system immediately. Call a Toyota
dealer for assistance.
5. If there are no obvious leaks, check the coolant reservoir. If it is dry, add
coolant to the reservoir while the hy-
brid system is running. Fill it about half
full.
CAUTION
Do not attempt to remove the radiator
cap when the hybrid system and ra-
diator are hot. Serious injury could
result from scalding hot fluid and
steam blown out under pressure.
If your hybrid system stalls
while driving130. 131.If your vehicle overheats

186
50p035a
Front
50p028b
Rear
If towing is necessary, we recommend
you to have it done by your Toyota
dealer or a commercial tow truck ser-
vice.
If towing service is not available in an
emergency, your vehicle may be tempo-
rarily towed by a cable or chain se-
cured to emergency towing eyelet in-
side of front bumper. Use extreme
caution when towing vehicles.
The front towing eyelet is provided in the
trunk. (For the front towing eyelet storage
location, see “—Required tools and spare
tire” on page 179.)
NOTICE
Only use specified towing eyelet;
otherwise your vehicle may be dam-
aged.
A driver must be in the vehicle to steer
it and operate the brakes.
Towing in this manner may be done only
on hardsurfaced roads for a short dis-
tance and at low speeds. Also, the
wheels, axles, drive train, steering and
brakes must all be in good condition.
CAUTION
Use extreme caution when towing
vehicles. Avoid sudden starts or er-
ratic driving maneuvers which
would place excessive stress on the
emergency towing eyelet and towing
cable or chain. The eyelet and tow-
ing cable or chain may break and
cause serious injury or damage.
In case of installing the front eyelet
on the vehicle, be sure to tighten
in the front eyelet securely. If the
tightening is loose, it may come off
when towing and result in death or
serious injury to the passenger in
the front vehicle or damage to that
vehicle.
NOTICE
Use only a cable or chain specifically
intended for use in towing vehicles.
Securely fasten the cable or chain to
the towing eyelet provided.
Before towing, release the parking brake
and put the selector lever in “N”. The key
must be in “ACC” (hybrid system off) or
“ON” (hybrid system on).
135.—Emergency towing