2004 TOYOTA PRIUS heating

126
(a) Discharge Warning Light
This light warns that the auxiliary battery
is being discharged.
If it comes on while you are driving, there
is a problem somewhere in the charging
system.
The hybrid system will continue to oper-
ate, however, until the auxiliary battery is
discharged. Turn off the air conditioning,
blower, radio, etc., and drive directly to
the nearest Toyota dealer or repair shop.(b) Low Engine Oil Pressure Warning
Light
This light warns that the engine oil pres-
sure is too low.
If it stays on while you are driving, pull
off the road to a safe place and stop the
engine immediately. Call a Toyota dealer
or qualified repair shop for assistance.
The light may come on when the oil level
is extremely low. It is not designed to
indicate low oil level, and the oil level
must be checked using the level dipstick.
NOTICE
Do not drive the vehicle with the
warning light on—even for one block.
It may ruin the engine.
(c) High Coolant Temperature Warning Light
The light operates to warn that the hybrid
system is almost over heating.
If it comes on while you are driving, stop
the vehicle and check your hybrid system.
For detailed instructions, see “If your ve-
hicle overheats” on page 242.
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.
NOTICE
 Do not remove the thermostat in
the cooling system as this may
cause the hybrid system to over-
heat. The thermostat is designed to
control the flow of coolant to keep
the temperature of the hybrid sys-
tem within the specified operating
range.
 Continued driving with the light on
could result in the overheating of
hybrid system.

183
SETTING OPERATION—manual control
When one of the manual control
switches is touched while operating in
automatic mode, the mode relevant to
the touched switch is set. Other condi-
tions continue to be adjusted automati-
cally.If manual air flow selection is desired—
27p113a
The outlets from which air is delivered
can be selected manually by touching the
switch. The function of each mode is as
follows:
1. Panel— Air flows mainly from the
instrument panel vents.
2. Bilevel— Air flows from both the floor
vents and the instrument panel vents.
3. Floor— Air flows mainly from the floor
vents.
4. Floor/Windshield— Air flows mainly
from the floor vents and windshield
vents.
The selected mode is highlighted in green. If quick heating or cooling is desired—
27p112a
Touch the “TEMP” switch and hold it until
the maximum figure or minimum figure ap-
pears.

184
If manual fan speed control is desired—
27p114a
1. Fan speed at low
2. Fan speed at high
The fan speed can be set to your desired
speed by touching the appropriate air flow
control switch. The higher the fan speed
is, the more air is delivered. Touching the
“OFF” switch turns off the fan.
To remove exterior windshield frost, use the
high speed setting.
The selected mode is highlighted in green.
If manual switching of air intake is de-
sired—
27p115a
The air intake control switch is used to
switch the air intake between the OUT-
SIDE AIR mode and RECIRCULATED AIR
mode.
With the switch in the OUTSIDE AIR
mode, the system will take fresh outside
air into the vehicle.
If quick circulation of cooled air is de-
sired, touch the air intake control switch
for RECIRCULATED AIR.
The indicator will come on in the instru-
ment cluster while the RECIRCULATED
AIR mode is selected.If recirculated air is used during heating,
the windows will fog up more easily.
If the hybrid system is turned off in the
OUTSIDE AIR mode, the automatic control
of the air intake is activated when the
hybrid system is turned on again.
2way air intake control
To improve fuel economy, OUTSIDE AIR
mode control changes when the air in-
take selector is set in OUTSIDE AIR on
the following conditions:
When the maximum heating is needed
with the air flow in “Floor” or “Floor/
Windshield”, fresh air flows in the up-
per compartment, while air is recircu-
lated in the lower compartment.
When cooling is needed, both fresh
and recirculate modes turns on.

206
CAUTION
Avoid inhaling the engine exhaust.
It contains carbon monoxide, which
is a colorless and odorless gas. It
can cause unconsciousness or even
death.
Make sure the exhaust system has
no holes or loose connections. The
system should be checked from
time to time. If you hit something,
or notice a change in the sound of
the exhaust, have the system
checked immediately.
Do not run the hybrid system in a
garage or enclosed area except for
the time needed to drive the vehicle
in or out. The exhaust gases cannot
escape, making this a particularly
dangerous situation.
Do not remain for a long time in a
parked vehicle with the hybrid sys-
tem running. If it is unavoidable,
however, do so only in an uncon-
fined area and adjust the heating or
cooling system to force outside air
into the vehicle.
Keep the back door closed while
driving. An open or unsealed back
door may cause exhaust gases to
be drawn into the vehicle.
To allow proper operation of your
vehicle’s ventilation system, keep
the inlet grilles in front of the wind-
shield clear of snow, leaves, or oth-
er obstructions.
If you smell exhaust fumes in the
vehicle, drive with the windows
open and the back door closed.
Have the cause immediately located
and corrected.
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.
Engine exhaust cautionsFacts about engine oil
consumption

213
The electric power steering system, us-
ing an electric motor, assists the turn-
ing of the steering wheel.
In the following cases, you may feel the
steering becomes heavy. However, the
electric power steering system warning
light does not come on. (Because it is
not a malfunction.)
When maneuvering the steering fre-
quently or keeping the steering wheel
turned fully while the vehicle is stopped
or moving very slowlyThe power steering effect will be re-
duced to prevent the system from over-
heating. Avoid turning the steering
wheel, or stop the vehicle. When you
leave the vehicle in the “IG −ON” mode
for a while, the system will become
cool.
NOTICE
If you repeat the operation which will
turn on the overheating prevention
function, the electric power steering
system may be damaged.
When the auxiliary battery is dis-
charged
Check the auxiliary battery’s condition.
If necessary, recharge or replace the
battery. For details, see “Checking aux-
iliary battery condition” on page 298.
When the steering wheel is operated
with the hybrid system not to be turned
on (with the “READY” light off)
The auxiliary battery capacity is de-
creased temporarily. The system re-
turns to normal some time after the
hybrid system is turned on.
If there is a problem somewhere in the
electric power steering system, the warn-
ing light comes on in the multi −information
display. For details, see “Multi −information
display” on page 124.30p003
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.
Electric power steering system Brake pad wear limit
indicators

233
CAUTION
Before driving off, make sure the
parking brake is fully released and
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 skid or
spin.
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 for engine coolant.
Only use “Toyota Super Long Life Coolant”
or similar high quality ethylene glycol
based non−silicate, non −amine, non− nitrite,
and non− borate coolant with long −life
hybrid organic acid technology. (Coolant
with long −life hybrid organic acid
technology is a combination of low
phosphates and organic acids.)
See “Checking the coolant level” on page
284 for details of coolant type selection.
For the U.S.A.—“Toyota Super Long Life
Coolant” is a mixture of 50% coolant and
50% deionized water. This coolant pro-
vides protection down to about −35 C
( − 31 F).
For Canada—“Toyota Super Long Life
Coolant” is a mixture of 55% coolant and
45% deionized water. This coolant pro-
vides protection down to about −42 C
( − 44 F).
NOTICE
Do not use plain water alone.
Winter driving tips

235
40p003b
Toyota does not recommend towing a
trailer with your Toyota. It is not de-
signed for trailer towing.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 cor-
rect pressure. Underinflation causes
tire wear and wastes fuel. See page
289 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. Stop−and− go 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.
Trailer towing How to save fuel and make
your vehicle last longer, too