coolant temperature TOYOTA PRIUS PRIME 2023 Owners Manual

1503-1. Instrument cluster
3-1.Instrument cluster
For the purpose of explanation, the following illustrations display all
warning lights and indicators illuminated.
The units used on the meters and some indicators may differ depending on
the target region.
Warning lights inform the driver
of malfunctions in the indicated
vehicle’s systems.
Warning lights and indicators
The warning lights and indicators on the instrument cluster,
overhead console panel and outside rear view mirrors inform
the driver of the status of the vehicle’s various systems.
Instrument cluster
Warning lights
(U.S.A.)
Brake system warning
light
*1 (  P.555)
(Canada)
(Red)
Brake system warning
light
*1 ( P.555)
(Yellow)
Brake system warning
light
*1 ( P.555)
Charging system warning
light
*2 (  P.555)
High coolant temperature
warning light ( P.556)
Low engine oil pressure
warning light
*2 (  P.556)
Hybrid system overheat
warning light
*2 (  P.556)

1603-1. Instrument cluster
compliance with the License.
You may obtain a copy of the
License at
http://www.apache.org/licenses/
LICENSE-2.0
Unless required by applicable law or
agreed to in writing, software distrib-
uted under the License is distributed
on an “AS IS” BASIS, WITHOUT
WARRANTIES OR CONDITIONS
OF ANY KIND, either express or
implied. See the License for the
specific language governing permis-
sions and limitations under the
License.
The multi-information display
can be switched between dis-
play and hidden. Switches the items of the odom-
eter, trip meter A, trip meter B
and (oil maintenance) by
pressing the “ODO TRIP”
switch.
When the trip meter is dis-
played, pressing and holding the
switch will reset the trip meter.
■Pop-up display
Distance until the next engine oil
change will be displayed when a
warning message indicating that
oil maintenance is required or
should be performed soon is
displayed.
WARNING
■The information display at
low temperatures
Allow the interior of the vehicle to
warm up before using the liquid
crystal information display. At
extremely low temperatures, the
display monitor may respond
slowly, and display changes may
be delayed.
NOTICE
■To prevent damage to the
engine and its components
The engine may be overheating if
“Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” is shown on the multi-
information display. In this case,
immediately stop the vehicle in a
safe place, and check the engine
after it has cooled completely.
(  P.594)
Switching the meter dis-
play
Using the “O DO TRIP”
switch

4366-1. Using the air conditioning system and defogger
switch.
■Defogging the rear window
(if equipped)
A defogger is used to defog the
rear window.
Press the rear window defogger
switch.
When the rear window defogger
switch is on, the indicator illumi-
nates on the rear window defogger
switch.
The defogger will automatically turn
off after 15 minutes.
■Defogging the rear window
and outside rear view mir-
rors (if equipped)
Defoggers are used to defog the
rear window and to remove rain-
drops, dew and frost from the
outside rear view mirrors.
Press the rear window and out-
side rear view mirror defoggers
switch.
When the rear window and outside
rear view mirror defoggers switch is
on, the indicator illuminates on the
rear window and outside rear view
mirror defoggers switch.
The defoggers will automatically
turn off after 15 minutes.
■When the outside temperature
exceeds 75°F (24°C) and the air
conditioning system is on
●In order to reduce the air condi-
tioning power consumption, the air
conditioning system may switch to
recirculated air mode automati-
cally.
This may also reduce fuel con-
sumption.
●Recirculated air mode is selected
as a default mode when the power
switch is turned to ON.
●It is possible to switch to outside
air mode at any time by pressing
the outside air mode switch.
■Heating
●In HV mode, the gasoline engine
may operate in order to extract
heat from the engine coolant via
the heater.
●In EV mode, heating is done by a
heat pump system.
• When the outside temperature is low or it is snowing, compared to
conventional vehicles, heating
may be less effective and warm
air may not come out.
• When the outside heat exchanger
is frosted over, fan speed declines
and it may become harder to heat
the interior. However, it is not a
malfunction. In this situation, the
air temperature from the outlets
may not change even though the
set temperature is raised.
• When “AUTO” switch is turned on, the heating is controlled opti-
mally. Therefore, the set heating
performance may not be achieved
even if the fan speed setting is
increased.
Outside heat exchanger
●In the following situations the gas-
oline engine may operate in order
to extract heat from the engine
coolant via the heater even in EV
mode.
• The outside temperature is approximately 75°F (24°C) or low
• Windshield defogger is operating
A

5007-3. Do-it-yourself maintenance
Radiator and
condenser
( P.508)

Tire inflation
pressure
( P.532)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.510)
• Water or washer
fluid containing
antifreeze (for win-
ter use)
• Funnel (used only for adding water or
washer fluid)
WARNING
The engine compartment contains
many mechanisms and fluids that
may move suddenly, become hot,
or become electrically energized.
To avoid death or serious injury,
observe the following precautions.
■When working on the engine
compartment
●Make sure that “POWER ON”
on the meter and the “READY”
indicator are both off.
●Keep hands, clothing and tools
away from the moving fan.
●Be careful not to touch the
engine, power control unit, radi-
ator, exhaust manifold, etc. right
after driving as they may be hot.
Oil and other fluids may also be
hot.
●Do not leave anything that may
burn easily, such as paper and
rags, in the engine compart-
ment.
ItemsParts and tools●Do not smoke, cause sparks or
expose an open flame to fuel or
the battery. Fuel and battery
fumes are flammable.
■When working near the elec-
tric cooling fan or radiator
grille
Be sure the power switch is OFF.
With the power switch in ON, the
electric cooling fan may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. ( P.508)
■Safety glasses
Wear safety glasses to prevent
flying or falling material, fluid
spray, etc., from getting in your
eyes.
NOTICE
■If you remove the air cleaner
filter
Driving with the air cleaner filter
removed may cause excessive
engine wear due to dirt in the air.

5047-3. Do-it-yourself maintenance
Engine oil filler cap (P.506)
Engine oil level dipstick ( P.504)
Brake fluid reservoir ( P.509)
Fuse boxes ( P.540)
Washer fluid tank ( P.510)
Radiator ( P.508)
Electric cooling fan
Condenser ( P.508)
Power control unit coolant reservoir ( P.507)
Engine coolant reservoir ( P.507)
■12-volt battery
 P.511
With the engine at operating
temperature and turned off,
check the oil level on the dip-
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
Checking the engine oil

5097-3. Do-it-yourself maintenance
7
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN”
lines on the tank.
■Adding fluid
1 Slide and lift up the rubber
strip to partly remove it, and then remove the clip remove
it as shown in the illustration.
2 Disconnect the claws and
remove the service cover.
3 Remove the reservoir cap.
4 Add brake fluid slowly while
checking the fluid level.
Make sure to check the fluid
type and prepare the necessary
WARNING
■When the electric cooling fan
is operating
Do not touch the engine compart-
ment.
With the power switch in ON, the
electric cooling fan may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. Be sure the
power switch is OFF when work-
ing near the electric cooling fan or
radiator grille.
Checking and adding the
brake fluid

5548-2. Steps to take in an emergency
Fluid leaks under the vehicle
(Water dripping from the air
conditioning after use is nor-
mal.)
 Flat-looking tires or uneven
tire wear
 High coolant temperature
warning light flashes or
comes on
 Changes in exhaust sound
 Excessive tire squeal when
cornering
 Strange noises related to the
suspension system
 Pinging or other noises
related to the hybrid system
 Engine missing, stumbling or
running roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side when braking
 Vehicle pulls heavily to one
side when driving on a level
road
 Loss of brake effectiveness,
spongy feeling, pedal almost
touches the floor
If you think something
is wrong
If you notice any of the fol-
lowing symptoms, your
vehicle probably needs
adjustment or repair. Con-
tact your Toyota dealer as
soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

5568-2. Steps to take in an emergency
■High coolant temperature warning light (warning buzzer)
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the multi-information display with a message.
■Hybrid system overheat warning light* (warning buzzer)
*: This light illuminates on the multi- information display with a message.
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates that the engine is overheating
Immediately stop the vehicle in a safe
place.
Handling method ( P.594)
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
 Immediately stop the vehicle in a safe
place and contact your Toyota dealer.
( P.506)
Warning lightDetails/Actions
Indicates that the hybrid system has overheated
 Stop the vehicle in a safe place. Handling
method ( P.595)
Warning lightDetails/Actions
(U.S.A.)
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engine control system;
 The electronic throttle control system; or
 The emission control system (if equipped)
 Have the vehicle inspected by your Toyota
dealer immediately.

5958-2. Steps to take in an emergency
8
When trouble arises
5Add coolant if necessary.
Water can be used in an emer-
gency if engine coolant is unavail-
able.
If water was added in an emer-
gency, have the vehicle inspected
at your Toyota dealer as soon as
possible.
6Start the hybrid system and
turn the air conditioning sys-
tem on to check that the radi-
ator cooling fan operates and
to check for coolant leaks
from the radiator or hoses.
The fan operates when the air con-
ditioning system is turned on imme-
diately after a cold start. Confirm
that the fan is operating by check-
ing the fan sound and air flow. If it is
difficult to check these, turn the air
conditioning system on and off
repeatedly. (The fan may not oper-
ate in freezing temperatures.)
7If the fan is not operating:
Stop the hybrid system
immediately and contact your
Toyota dealer.
If the fan is operating:
Have the vehicle inspected at
the nearest Toyota dealer.
8 Check if “Engine Coolant
Temp High Stop in a Safe
Place See Owner’s Manual” is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact
your Toyota dealer.
If the message is not displayed:
Have the vehicle inspected at the
nearest Toyota dealer.
■If “Hybrid System Over-
heated Output Power
Reduced” is shown on the
multi-information display
1 Stop the vehicle in a safe
place.
2 Stop the hybrid system and
carefully lift the hood.
3 After the hybrid system has
cooled down, inspect the
hoses and radiator core (radi-
ator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the “MAX”
A
B

5968-2. Steps to take in an emergency
and “MIN” lines on the reser-
voir.
Reservoir
“MAX” line
“MIN” line
5 Add coolant if necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable.
If water was added in an emer-
gency, have the vehicle inspected
at your Toyota dealer as soon as
possible.
6After stopping the hybrid sys-
tem and waiting for 5 minutes
or more, start the hybrid sys-
tem again and check for the
multi-information display.
If the message does not disappear:
Stop the hybrid system and contact
your Toyota dealer.
If the message is not displayed:
The hybrid system temperature has dropped and the vehicle may be
driven normally.
However, if the message appears
again frequently, contact your
Toyota dealer.
A
B
C
WARNING
■When inspecting under the
hood of your vehicle
Observe the following precau-
tions.
Failure to do so may result in seri-
ous injury such as burns.
●If steam is seen coming from
under the hood, do not open the
hood until the steam has sub-
sided. The engine compart-
ment may be very hot.
●After the hybrid system has
been turned off, check that the
“READY” indicator is off.
When the hybrid system is oper-
ating, the gasoline engine may
automatically start, or the cool-
ing fan may suddenly operate
even if the gasoline engine
stops. Do not touch or approach
rotating parts such as the fan,
which may lead to fingers or
clothing (especially a tie, a scarf
or a muffler) getting caught,
resulting in serious injury.
●Do not loosen the coolant reser-
voir cap while th e hybrid system
and radiator are hot.
High temperature steam or
coolant could spray out.
NOTICE
■When adding engine/power
control unit coolant
Add coolant slowly after the
hybrid system has cooled down
sufficiently. Adding cool coolant to
a hot hybrid system too quickly
can cause damage to the hybrid
system.