Page 588 of 792
588
PRIUS PRIME_OM_OM47C77U_(U)
7-3. Do-it-yourself maintenance
Engine compartment
Engine coolant reservoir ( P. 592)
Fuse boxes ( P. 638)
Engine oil level dipstick ( P. 589)
Engine oil filler cap ( P. 590)
Brake fluid reservoir ( P. 598) Washer fluid tank (
P. 600)
12-volt battery ( P. 595)
Power control unit coolant
reservoir ( P. 592)
Radiator ( P. 594)
Condenser ( P. 594)
Electric cooling fans1
2
3
4
5
6
7
8
9
10
11
Page 592 of 792
592
PRIUS PRIME_OM_OM47C77U_(U)
7-3. Do-it-yourself maintenance
The coolant level is satisfactory if it is between the “FULL” a nd “LOW”
lines on the reservoir when the hybrid system is cold.
■Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to
the “FULL” line. ( P. 709)
■
Power control unit coolant reservoir Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to
the “FULL” line. ( P. 709)
Coolant
1
2
3
1
2
3
Page 593 of 792

PRIUS PRIME_OM_OM47C77U_(U)
5937-3. Do-it-yourself maintenance
7
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.
Page 594 of 792
594
PRIUS PRIME_OM_OM47C77U_(U)
7-3. 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 vehicle inspected by your Toyota dea l e r.
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.
Page 661 of 792
661
PRIUS PRIME_OM_OM47C77U_(U)
8
When trouble arises
8-2. 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
Page 664 of 792

6648-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
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. 709)
• 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. 444)
• The light will come on when the Parking Support Brake
function is operating ( P. 448)
• The light will flash when the system cannot be temporar- ily used ( P. 452)
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.
Driver’s and front passenger’ s seat belt reminder light
(warning buzzer)
*4, 5
Warns the driver and/or front passenger to fasten their
seat belts
Fasten the seat belt.
If the front passenger’s seat is occupied, the front
passenger’s seat belt also needs to be fastened to
make the warning light (warning buzzer) turn off.
Warning lightWarning light/Details/Actions
Page 712 of 792

7128-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
After stopping the hybrid system and waiting for 5 minutes or
more, start the hybrid system again and check if “Hybrid System
Overheated” is shown on the multi-information display.
If the message d oes 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.
WARNING
■ To prevent an accident or injury when inspecting under the hood of
your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
● If steam is seen coming from under the hood, do not open the ho od until
the steam has subsided. The engine compartment may be very hot.
● After the hybrid system has been turned off, check that the “Ac cessory”,
“Ignition ON” or mileage display ( P. 210) on the main display and the
“READY” indicator are off.
When the hybrid system is operating, the gasoline engine may au tomati-
cally start, or the cooling fans 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 reservoir caps while the hybrid syste m and radi-
ator are hot.
High temperature steam or coolant could spray out.
6
Page 713 of 792
7138-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
8
When trouble arises
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.
■ To prevent damage to the cooling system
Observe the following precautions:
● Avoid contaminating the coolant with foreign matter (such as sand or dust
etc.).
● Do not use any coolant additive.