2021 TOYOTA PRIUS coolant temperature

PRIUS_OM_OM47E09U_(U)
1092. Instrument cluster
2
Instrument cluster
*1: These lights turn on when the power switch is turned to ON mode to indi-
cate that a system check is being performed. They will turn off after the
hybrid system is on, or after a few seconds. There may be a malfunction in
a system if a light does not come on, or turn off. Have the veh icle
inspected by your Toyota dealer.
*2: The light flashes or illuminates to indicate a malfunction.
*3: The light flashes to indicate a malfunction.
*1High coolant temperature warning light P. 594
*1, 3PKSB OFF indicator (if equipped)P. 594
Open door warning light P. 594
Low fuel level warning lightP. 594
Driver’s and front passenger’s seat belt
reminder light P. 595
Rear passengers’ seat belt reminder light
(U.S.A.)P. 595
Rear passengers’ seat belt reminder light
(Canada)P. 595
*1Master warning light
P. 595
*1Tire pressure warning lightP. 595
Warning lightsPages

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2. Instrument cluster
■BSM (Blind Spot Monitor) outsid e rear view mirror indicators
(if equipped) ( P. 349)
• When the BSM function is enabled on the screen of the multi-i nfor-
mation display, the power switch is turned to ON mode.
If the system is functioning correctly, the BSM outside rear vi ew mirror indi-
cators will turn off after a few seconds.
If the BSM outside rear view mirror indicators do not illuminat e or do not
turn off, there may be a malfunction in the system.
If this occurs, have the vehicle inspected by your Toyota deale r.
●
Indicators are also displayed on the out-
side rear view mirrors.
● In order to confirm operation, the BSM
outside rear view mirror indicators illumi-
nate in the following situations:
• When the power switch is in ON
mode, the BSM function is enabled
on the screen of the multi-infor-
mation display.
WARNING
■If a safety system warning light does not come on
Should a safety system light such as the ABS and SRS warning li ght not
come on when you start the hybrid system, this could mean that these sys-
tems are not available to help protect you in an accident, whic h could result
in death or serious injury. Have the vehicle inspected by your Toyota dealer
immediately if this occurs.
NOTICE
■ To prevent damage to the engine and its components
The engine may be overheating if the high coolant temperature warning
light comes on or flashes. In this case, immediately stop the vehicle in a
safe place, and check the engine after it has cooled completely . (P. 656)

PRIUS_OM_OM47E09U_(U)
5136-3. Do-it-yourself maintenance
6
Maintenance and care
Tire inflation
pressure
( P. 542)• Tire pressure gauge
• Compressed air source
Washer fluid
( P. 5 3 0 )• 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 the “Accessory”, “Ignition ON” or mileage displa y
( P. 116) on the main display 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, radiator, 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 r ags, in the
engine compartment.
● Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes
are flammable.
● Be extremely cautious when working on the 12-volt battery. It c ontains poi-
sonous and corrosive sulfuric acid.
■ When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
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. ( P. 524)
■ Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc.
from getting in your eyes.
ItemsParts and tools

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
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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

591
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7
When trouble arises
7-2. Steps to take in an emergency
If you think something is wrong
●Fluid leaks un der the vehicle
(Water dripping from the air conditioning a fter use is normal.)
● Flat-looking tires or uneven tire wear
● High coolant temperature warni ng 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, stumb ling or running roughly
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one s ide when driving on a level road
● Loss of brake effectiveness, spongy feeling, pedal almost touch es
the floor
If you notice any of the followi ng symptoms, your vehicle proba -
bly needs adjustment or repair. Contact your Toyota dealer as
soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

5947-2. Steps to take in an emergency
PRIUS_OM_OM47E09U_(U)
Slip indicator lightIndicates a malfunction in:
• The VSC system;
• The TRAC system; or
• The hill-start assist control system
 Have the vehicle inspected by your Toyota dealer
immediately.
The light will flash when the ABS, VSC or TRAC system is
operating.
High coolant temperature warning light • When the light flashes:
Indicates that the engine coolant temperature is too high
The light changes from a flashing to a solid light when
the temperature further increases
 Immediately stop the vehicle in a safe place. ( P. 656)
• When the light comes on without flashing: Indicates a malfunction in the exhaust heat recirculator
system
 Have the vehicle inspected by your Toyota dealer
immediately.
(Flashes)
(If equipped)
PKSB OFF indicator
Indicates a malfunction in the Parking Support Brake func-
tion
 Have the vehicle inspected by your Toyota dealer.
The warning light will operate as follows, even when the
system is not malfunctioning:
• The light will come on when the Parking Support Brake function is turned off ( P. 375)
• The light will come on when the Parking Support Brake function is operating ( P. 379)
• The light will flash when the system cannot be temporar- ily used ( P. 383)
Open door warning light (warning buzzer)*3
Indicates that a door is not fully closed
 Check that all the doors are closed.
Low fuel level warning light
Indicates that remaining fuel is approximately 1.7 gal.
(6.4 L, 1.4 Imp.gal.) or less
 Refuel the vehicle.
Warning lightWarning light/Details/Actions

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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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