2021 TOYOTA PRIUS cooling

PRIUS_OM_OM47E09U_(U)
5236-3. Do-it-yourself maintenance
6
Maintenance and care
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene
glycol based non-silicate, non-amine, non-nitrite, and non-bora te coolant with
long-life hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -31 F [-35 C])
Canada:
“Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deion-
ized water. (Minimum temperature: -44 F [-42 C])
For more details about coolant, contact your Toyota dealer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit c oolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Toyota dealer test the cap and check for
leaks in the cooling system.
WARNING
■ When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir c aps.
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
■ When adding coolant
Coolant is neither plain water nor straight antifreeze. The cor rect mixture of
water and antifreeze must be used to provide proper lubrication , corrosion
protection and cooling. Be sure to read the antifreeze or coolant label.
■ If you spill coolant
Be sure to wash it off with water to prevent it from damaging p arts or paint.

524
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of
their condition, have your vehic le inspected by your Toyota dea ler.
Check the 12-volt battery as follows:
■12-volt battery exterior
Make sure that the 12-volt battery terminals are not corroded a nd
that there are no loose connecti ons, cracks, or loose clamps.
Terminals
Radiator and condenser
WARNING
■ When the hybrid system is hot
Do not touch the radiator or condenser as they may be hot and c ause seri-
ous injuries, such as burns.
■ When the electric cooling fans are operating
Do not touch the engine compartment.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. Be sure the power switch is off when working near the electric cool-
ing fans or radiator grille.
12-volt battery

551
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
6
Maintenance and care
Cleaning the hybrid batter y (traction bat-
ter y) air intake vent and filter
Remove the dust from the air
intake vent with a vacuum
cleaner, etc.
Make sure to only use a vacuum to
suck out dust and clogs. Attempt-
ing to blow out dust and clogs
using an airgun, etc. may push it
into the air intake vent. ( P. 5 5 5 )
If dust and clogs cannot be completely removed with the air int ake
vent cover installed, remove t he cover and clean the filter.
Turn the power switch off.
Using a Phillips screwdriver,
remove the clip.
To prevent the fuel economy from being affected, visually
inspect the hybrid battery (traction battery) air intake vent p eri-
odically for dust and clogs. If i t is dusty or clogged or if “Mainte-
nance required for Traction batt ery cooling parts See owner’s
manual” is shown on the multi-info rmation display, clean the air
intake vent using the following procedures:
Cleaning the air intake vent
If dust and clogs cannot be completely removed
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554
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
■Scheduled maintenance of the air intake vent is necessary when
In some situations such as when the vehicle is used frequently or in heavy
traffic or dusty areas, the air intake vent may need to be clea ned more regu-
larly. For details, refer to the “Scheduled Maintenance Guide” or “Owner’s
Manual Supplement”.
■ Cleaning the air intake vent
●Dust in the air intake vent may interfere with the cooling of t he hybrid battery
(traction battery). If charging/discharging of the hybrid batte ry (traction bat-
tery) becomes limited, the distance that the vehicle can be dri ven using the
electric motor (traction motor) may be reduced and the fuel eco nomy may
be reduced. Inspect and clean the air intake vent periodically.
● Improper handling of the air intake vent cover and filter may result in dam-
age to them. If you have any concerns about cleaning the filter , contact your
Toyota dealer.
■ If “Maintenance required for Traction battery cooling parts See owner’s
manual” is shown on the mu lti-information display
● If this warning message is shown on the multi-information displ ay, remove
the air intake vent cover and clean the filter. ( P. 551)
● After cleaning the air intake vent, start the hybrid system and check that the
warning message is no longer shown.
It may take approximately 20 minutes after the hybrid system is started until
the warning message disappears. If the warning message does not disap-
pear, have the vehicle inspected by your Toyota dealer.
WARNING
■ When cleaning the air intake vent
● Do not use water or other liquids to clean the air intake vent. If water is
applied to the hybrid battery (traction battery) or other components, a mal-
function or fire may occur.
● Before cleaning the air intake vent, make sure to turn the power switch off
to stop the hybrid system.
■ When removing the air intake vent cover
Do not touch the service plug located near the air intake vent. ( P. 91)

PRIUS_OM_OM47E09U_(U)
5556-3. Do-it-yourself maintenance
6
Maintenance and care
NOTICE
■When cleaning the air intake vent
■ To prevent damage to the vehicle
● Do not allow water or foreign matter to enter the air intake ve nt when the
cover is removed.
● Carefully handle the removed filter so that it will not be dama ged. If the fil-
ter is damaged, have it replaced with a new filter by your Toyota dealer.
● Make sure to reinstall the filter and cover to their original positions after
cleaning.
● Do not install anything to the air intake vent other than the exclusive filter
for this vehicle or use the vehicle without the filter installe d.
■ If “Maintenance required for Traction battery cooling parts See owner’s
manual” is shown on the mu lti-information display
If the vehicle is continuously driven with the warning message (indicating
that charging/discharging of the hybrid battery [traction batte ry] may
become limited) displayed, the hybrid battery (traction battery ) may mal-
function. If the warning message is shown, clean the air intake vent immedi-
ately.
When cleaning the air intake vent, make
sure to only use a vacuum to suck out
dust and clogs. If a compressed air blow
gun, etc. is used to blow out dust and
clogs, the dust or clogs may be pushed
into the air intake vent, which may affect
the performance of the hybrid battery
(traction battery) and cause a malfunc-
tion.

6077-2. Steps to take in an emergency
PRIUS_OM_OM47E09U_(U)
7
When trouble arises
■If “Shift System Malfunction See Owner’s Manual” is shown
Indicates a malfunction in the shift control system. Immediatel y have the sys-
tem inspected by your Toyota dealer.
The system may not operate properly.
■ If “Low 12-Volt Battery Apply Parking Brake Securely While Park ing See
Owner’s Manual” is shown
Indicates that the 12-volt battery charge is insufficient. Char ge or replace the
12-volt battery.
● When the message is shown, the hybrid system may not start or t he shift
position may not be changed normally. (Coping method: P. 609)
● After charging the 12-volt battery, the message may not go off until the shift
position is changed from P.
■ If “Shifting Unavailable Low 12-Volt Battery See Owner’s Manual ” is
shown
Indicates that the shift position cannot be changed because the voltage of the
12-volt battery drops. Charge or replace the 12-volt battery.
(Coping method in the case the 12-volt battery is discharged: P. 650)
■ If “Hybrid System Overheated. Reduced Output Power.” is shown
The message may be shown when driving under severe operating co nditions.
(For example, when driving up a long steep hill or driving up a steep hill in
reverse.)
Coping method: P. 656
■ If “Maintenance required for Traction battery cooling parts See owner’s
manual” is shown
The filter may be clogged, the air intake vent may be blocked or there may be
a gap in the duct.
● If the air intake vent is dirty, refer to P. 551 for information on how to clean
the air intake vent.
● If the message is shown when the air intake vent is not dirty, have the vehi-
cle inspected by your Toyota dealer.
■ If “Traction Battery Needs to be Protected Refrain From the Use of
Position” is shown
This message may be displayed when the shift position is in N.
As the hybrid battery (traction battery) can not be charged when the shift
position is in N, shift the shift position to P when the vehicle is stopped.
■ If “Traction Battery Needs to be Protected Shift into to Resta rt” is
shown
This message is displayed when the hybrid battery (traction battery) charge
has become extremely low because the vehicle has been left with the N shift
position selected for a certain amount of time.
When operating the vehicle, shift to P and restart the hybrid s ystem.

6557-2. Steps to take in an emergency
PRIUS_OM_OM47E09U_(U)
7
When trouble arises
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure that they do not beco me entan-
gled in the cooling fans, etc.

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PRIUS_OM_OM47E09U_(U)
7-2. Steps to take in an emergency
If your vehicle overheats
■If the high coolant temperature warning light comes on or
flashesStop the vehicle in a safe place and turn off the air conditioning
system, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has cooled down sufficiently, inspect t he
hoses and radiator core (ra diator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
your Toyota dealer.
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light ( P. 594) comes on
or flashes, or a loss of hybrid system power is experienced. (F or
example, the vehicle s peed does not increase.)
● “Hybrid System Overheated” is shown on the multi-information
display.
● Steam comes out from under the hood.
Correction procedures
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