2003 TOYOTA PRIUS engine

155
FUNCTIONS OF ENGINE OIL
Engine oil has the primary functions of
lubricating and cooling the inside of the
engine, and plays a major role in main-
taining the engine in proper working order.
ENGINE OIL CONSUMPTION
It is normal that an engine should con-
sume some engine oil during normal
engine operation. The causes of oil
consumption in a normal engine are as
follows.
Oil is used to lubricate pistons, piston
rings and cylinders. A thin film of oil
is left on the cylinder wall when a
piston moves downwards in the cylin-
der. High negative pressure generated
when the vehicle is decelerating sucks
some of this oil into the combustion
chamber. This oil as well as some part
of the oil film left on the cylinder wall
is burned by the high temperature com-
bustion gases during the combustion
process.
Oil is also used to lubricate the stems
of the intake valves. Some of this oil
is sucked into the combustion chamber
together with the intake air and is
burned along with the fuel. High tem-
perature exhaust gases also burn the
oil used to lubricate the exhaust valve
stems.
The amount of engine oil consumed de-
pends on the viscosity of the oil, the
quality of the oil and the conditions the
vehicle is driven under.
More oil is consumed by highspeed driv-
ing and frequent acceleration and decel-
eration.
A new engine consumes more oil, since
its pistons, piston rings and cylinder walls
have not become conditioned.
When judging the amount of oil con-
sumption, note that the oil may become
diluted and make it difficult to judge
the true level accurately. As an example, if a vehicle is used for
repeated short trips, and consumes a nor-
mal amount of oil, the dipstick may not
show any drop in the oil level at all, even
after 1000 km (600 miles) or more. This
is because the oil is gradually becoming
diluted with fuel or moisture, making it
appear that the oil level has not changed.
The diluting ingredients evaporate out
when the vehicle is then driven at high
speeds, as on an expressway, making it
appear that oil is excessively consumed
after driving at high speeds.
IMPORTANCE OF ENGINE OIL LEVEL
CHECK
One of the most important points in prop-
er vehicle maintenance is to keep the en-
gine oil at the optimum level so that oil
function will not be impaired. Therefore, it
is essential that the oil level be checked
regularly. Toyota recommends that the oil
level be checked every time you refuel
the vehicle.
NOTICE
Failure to check the oil level regularly
could lead to serious engine trouble
due to insufficient oil.
111.Facts about engine oil
consumption

156
For detailed information on oil level check,
see “Checking the engine oil level” on
page 214 in Section 82.
Your engine is fitted with iridiumtipped
spark plugs.
NOTICE
Use only iridiumtipped spark plugs
and do not adjust gaps for your en-
gine performance and smooth drivabil-
ity.
REGENERATIVE BRAKE
When the brake is applied, the electric
motor used as a generator converts kinet-
ic energy into electric energy.
The regenerative brake works in the fol-
lowing operations.1. When the accelerator pedal is re- leased, the reduced speed equal to en-
gine braking in a gasolinefueled ve-
hicle is obtained in accordance with the
running mode position of the selector
lever.
2. When the brake pedal is depressed with the selector lever in “D” or “B”,
the regenerative brake works.
112.Iridiumtipped spark plugs 113.Brake system

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).

158
Depressing the brake pedal on slippery
road surfaces such as on the manhole
cover, the steel plate under the construc-
tion, joints in the bridge, etc. on a rainy
day tends to activate the antilock 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 is started. This means that the
antilock brake system is in the self
check mode, and does not indicate a mal-
function.
When the antilock brake system is ac-
tivated, the following conditions may
occur. They do not indicate a malfunc-
tion of the system:
You may hear the antilock brake sys-
tem operating and feel the brake pedal
pulsating and the vibrations of the ve-
hicle body and steering wheel. You
may also hear the motor sound in the
engine compartment even after the ve-
hicle is stopped.
At the end of the antilock brake sys-
tem activation, the brake pedal may
move a little forward.
CAUTION
Do not overestimate the antilock
brake system: Although the antilock
brake system assists in providing ve-
hicle control, it is still important to
drive with all due care and maintain
a moderate speed and safe distance
from the vehicle in front of you, be-
cause there are limits to the vehicle
stability and effectiveness of steering
wheel operation even with the anti
lock brake system on.
If tires grip performance exceeds its
capability, or if hydroplaning occurs
during high speed driving in the rain,
the antilock brake system does not
provide vehicle control.
Antilock brake system is not de-
signed to shorten the stopping dis-
tance: Always drive at the moderate
speed and maintain a safe distance
from the vehicle in front of you.
Compared with vehicles without an
antilock brake system, your vehicle
may require a longer stopping dis-
tance in the following cases:
Driving on rough, gravel or snow
covered roads.
Driving with tire chains installed.
Driving over the steps such as the
joints on the road.
Driving on roads where the road
surface is pitted or has other differ-
ences in surface height.
Install all 4 tires of specified size at
appropriate pressure: The antilock
brake system detects vehicle speeds
using the speed sensors for respec-
tive wheels’ turning speeds. The use
of tires other than specified may fail
to detect the accurate turning speed,
resulting in a longer stopping dis-
tance.

161
30p004a
The vehicle identification number (VIN)
is the legal identifier for your vehicle.
This number is on the left top of the
instrument panel, and can be seen
through the windshield from outside.
This is the primary identification number
for your Toyota. It is used in registering
the ownership of your vehicle.
30p005a
The vehicle identification number (VIN) is
also on the Certification Label.
30p006a
Engine number
Motor number
The engine and motor number plates
are installed on the engine and trans-
axle case as shown.
Your Toyota’s identification—
—Vehicle identification116.
number —Engine and motor number

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.