2021 TOYOTA HIGHLANDER HYBRID radiator

4086-2. Maintenance
HIGHLANDER HV_U
General maintenance
Listed below are the general
maintenance items that
should be performed at the
intervals specified in the
“Owner’s Warranty Informa-
tion Booklet” or “Owner’s
Manual Supplement/Sched-
uled Maintenance Guide”. It
is recommended that any
problem you notice should
be brought to the attention
of your Toyota dealer or
qualified service shop for
advice.
WARNING
■If the hybrid system is operat-
ing
Turn the hybrid system off and
ensure that there is adequate
ventilation before performing
maintenance checks.
Engine compartment
ItemsCheck points
Brake fluid
Is the brake fluid at
the correct level?
(  P.420)
Engine/power
control unit
coolant
Is the
engine/power con-
trol unit coolant at
the correct level?
( P.418)
Engine oil
Is the engine oil at
the correct level?
( P.416)
Exhaust sys-
temThere should not
be any fumes or
strange sounds.
Radiator/con-
denser
The radiator and
condenser should
be free from for-
eign objects.
( P.419)
Washer fluid
Is there sufficient
washer fluid?
( P.420)
Luggage compartment
ItemsCheck points
12-volt batteryCheck the connec-
tions. ( P.421)
Vehicle interior
ItemsCheck points
Accelerator
pedal
• The accelerator
pedal should
move smoothly
(without uneven
pedal effort or
catching).
Hybrid trans-
mission “Park”
mechanism
• When parked on a slope and the
shift lever is in P,
is the vehicle
securely
stopped?
ItemsCheck points

4136-3. Do-it-yourself maintenance
6
Maintenance and care
HIGHLANDER HV_U
Hybrid battery
(traction bat-
tery) air intake
vent (P.441)• Vacuum cleaner,
etc.
• Phillips screw- driver
Headlight aim
( P.448)• Phillips-head
screwdriver
Light bulbs
( P.449)
• Bulb with same
number and
wattage rating as
original
• Phillips-head screwdriver
• Flathead screw- driver
• Wrench
Radiator and
condenser
(  P.419)

Tire inflation
pressure
( P.436)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.420)
• Water or washer
fluid containing
antifreeze (for
winter 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.
ItemsParts and tools■When working on the engine
compartment
●Make sure that the “ACCES-
SORY” or “IGNITION ON” on
the multi-information display
and the “READY” indicator are
both off.
●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.
●Do not smoke, cause sparks or
expose an open flame to fuel.
Fuel 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 fa n may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. ( P.419)
■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.

4166-3. Do-it-yourself maintenance
HIGHLANDER HV_U
Engine coolant reservoir ( P.418)
Fuse boxes ( P.446)
Engine oil filler cap ( P.417)
Engine oil level dipstick ( P.417)
Brake fluid reservoir ( P.420)
Washer fluid tank ( P.420)
Electric cooling fan
Condenser ( P.419)
Radiator ( P.419)
Power control unit coolant reservoir ( P.419)
■12-volt battery
 P. 4 2 1
With the engine at operating
temperature and turned off,
check the oil level on the dip-
Engine compar tment
Components
Checking and adding the
engine oil

4196-3. Do-it-yourself maintenance
6
Maintenance and care
HIGHLANDER HV_U
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. (P.504)
■Power control unit coolant
reservoir
The coolant level is satisfactory
if it is between the “FULL” and
“LOW” lines on the reservoir
when the hybrid system is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. ( P.504)
■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-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is
a mixture of 50% coolant and 50%
deionized water. (Minimum tem-
perature: -31°F [-35°C])
Canada: “Toyota Super Long Life Coolant” is
a mixture of 55% c
oolant and 45%
deionized water. (Minimum tem-
perature: -44°F [-42°C])
For more details about coolant, con-
tact your Toyota dealer.
■If the coolant level drops within
a short time of replenishing
Visually check the radiator, hoses,
engine/power control unit coolant
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 sys-
tem.
Check the radiator and con-
WARNING
■When the hybrid system is
hot
Do not remove the engine/power
control unit coolant reservoir caps
and radiator cap.
The cooling system may be under
pressure and may spray hot cool-
ant if the cap is removed, causing
serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor
straight antifreeze. The correct
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 parts or
paint.
Checking the radiator and
condenser

5047-2. Steps to take in an emergency
HIGHLANDER HV_U
If the engine coolant tempera-
ture gauge enters the red
zone or “Engine Coolant
Temp High Stop in a Safe
Place See Owner’s Manual”
is shown on the multi-informa-
tion display
1 Stop the vehicle in a safe
place and turn off the air con-
ditioning system, and then
stop the hybrid system.
2 If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the hybrid system has
cooled down sufficiently,
inspect the hoses and radia-
tor core (radiator) for any
leaks.
Radiator
Cooling fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
If your vehicle over-
heats
The following may indicate
that your vehicle is over-
heating.
The needle of the engine
coolant temperature gauge
( P.89) enters the red zone
or a loss of hybrid system
power is experienced. (For
example, the vehicle speed
does not increase.)
 “Engine Coolant Temp High
Stop in a Safe Place See
Owner’s Manual” or “Hybrid
System Overheated Output
Power Reduced” is shown
on the multi-information dis-
play.
 Steam comes out from
under the hood.
Correction procedures

5057-2. Steps to take in an emergency
7
When trouble arises
HIGHLANDER HV_U
Radiator cap
5 Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
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 op erating by check-
ing the fan sound and air flow. If it is
difficult to check th ese, turn the air
conditioning system on and off
repeatedly. (The fan may not oper-
ate in freezing temperatures.)
7 If 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 fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the

5067-2. Steps to take in an emergency
HIGHLANDER HV_U
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
5 Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
6After stopping the hybrid sys-
tem and waiting for 5 minutes
or more, start the hybrid sys-
tem again and check if
“Hybrid System Overheated
Output Power Reduced” is
shown on the 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 m
essage appears
again frequently, contact your Toy-
ota dealer.
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 radiator cap
and the coolant reservoir caps
while the 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.

567Alphabetical Index
HIGHLANDER HV_UParking lights
Light switch .......................... 229
Replacing light bulbs ............ 449
Parking Support Brake function (for rear-crossing vehicles) . 318Function ............................... 318
Parking Support Brake function (static objects) ...................... 312Function ............................... 312
PCS (Pre-Collision System) Function ............................... 249
PCS OFF switch................... 252
Warning light ........................ 472
Personal lights ....................... 362
PKSB (Parking Support Brake) ............................................... 305Warning message ................ 310
Power control unit .................... 75
Power control unit coolant Capacity ............................... 513
Checking .............................. 418
Preparing and c hecking before
winter.................................. 333
Power outlets .................. 383, 384
Power steering (Electric power steering system)................... 326Warning light ........................ 469
Power switch .......................... 213 Auto power off function ........ 216
Changing the power switch modes ................................ 216
Power switch ( engine switch)
If your vehicle has to be stopped in an emergency................. 458
Power windows Door lock linked window opera-tion ..................................... 180
Jam protection function ........ 179
Operation ............................. 179
Window lock switch .............. 181
Pre-Collision System (PCS) Function ............................... 249 PCS OFF switch ...................252
Warning light.........................472
Predictive deceleration support .................................................74
Predictive SOC control ............74
R
Radar cruise control (dynamic radar cruise control with
full-speed range)...................271
Radiator ...................................419
RCTA Function................................300
Warning message.................301
RCTA function .........................302
Rear automatic air conditioning system ...................................354
Rear Cross Traffic Alert (RCTA) ...............................................300
Rear door sunshades .............389
Rear seats ...............................154 Head restraints .....................162
Seat heaters ....... ..................358
Rear side marker lights Light switch...........................229
Replacing light bulbs ............449
Rear turn signal lights Replacing light bulbs ............449
Turn signal lever ...................223
Rear view mirror Digital Rearview Mirror .........167
Inside rear view mirror ..........166
Outside rear view mirrors .....177
Rear window defogger ...344, 348
Refueling Capacity ............................... 511
Fuel types ............................. 511
If the fuel filler door cannot be opened ...............................495
Opening the fuel tank cap ....240
Regenerative braking ...............72