2023 TOYOTA HIGHLANDER HYBRID coolant temperature

3966-3. Do-it-yourself maintenance
Engine coolant reservoir ( P.399)
Fuse boxes ( P.425)
Engine oil filler cap ( P.397)
Engine oil level dipstick ( P.397)
Brake fluid reservoir ( P.400)
Washer fluid tank ( P.401)
Electric cooling fan
Condenser ( P.400)
Radiator ( P.400)
Power control unit coolant reservoir ( P.399)
■12-volt battery
 P. 4 0 2
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

4437-2. Steps to take in an emergency
7
When trouble arises
When using a flat-bed truck to
transport the vehicle, use tire
strapping belts. Refer to the
owner's manual of the flat-bed
truck for the tire strapping
method.
In order to suppress vehicle
movement during transporta-
tion, set the parking brake and
turn the power switch off. 
Fluid leaks under the vehicle
(Water dripping from the air
conditioning after use is nor-
mal.)
 Flat-looking tires or uneven
tire wear
 Engine coolant temperature
gauge needle continually
points higher than normal
 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
NOTICE
■Towing with a sling-type truck
Do not tow with a sling-type truck
to prevent body damage.
2WD models
AWD models
Using a flatbed truck
NOTICE
■To prevent damage to the
vehicle during emergency
towing
Do not secure cables or chains to
the suspension components.
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

4457-2. Steps to take in an emergency
7
When trouble arises
■Brake system warning light
■Brake system warning light
■High coolant temperature warning light* (warning buzzer)
*: This light illuminat es on the multi-information display.
If a war ning light tur ns on or a war ning buzzer
sounds
Calmly perform the following actions if any of the warning
lights comes on or flashes. If a light comes on or flashes, but
then goes off, this does not necessarily indicate a malfunction
in the system. However, if this continues to occur, have the
vehicle inspected by your Toyota dealer.
Actions to the warning lights or warning buzzers
Warning lightDetails/Actions
(U.S.A.)
or
(red)
(Canada)
Indicates that:
 The brake fluid level is low; or
 The brake system is malfunctioning
 Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer. Continuing to drive the vehi-
cle may be dangerous.
Warning lightDetails/Actions
(yellow)
Indicates a malfunction in:
The regenerative braking system;
 The electronically contr olled brake system; or
 The electric parking brake
 Have the vehicle inspected by your Toyota dealer
immediately.
Warning lightDetails/Actions
Indicates that the engine coolant temperature is too high
Immediately stop the vehicle in a safe place.
Handling method ( P.484)

4847-2. Steps to take in an emergency
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
NOTICE
■When handling jumper cables
When connecting the jumper
cables, ensure that they do not
become entangled in the cooling
fan or belt.
■To prevent damaging the
vehicle
The exclusive jump starting termi-
nal is to be used when charging
the 12-volt battery from another
vehicle in an emergency. It cannot
be used to jump start another
vehicle.
If your vehicle over-
heats
The following may indicate
that your vehicle is over-
heating.
 The needle of the engine
coolant temperature gauge
( P.87) 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-
p l a y.
 Steam comes out from
under the hood.
Correction procedures

4857-2. Steps to take in an emergency
7
When trouble arises
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 cont act your Toyota
dealer.
4 The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line 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 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

4867-2. Steps to take in an emergency
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 cont act your Toyota
dealer.
4 The coolant level is satisfac-
tory if it is between the “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.

4877-2. Steps to take in an emergency
7
When trouble arises
However, if the message 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.
■To prevent damage to the
cooling system
Observe the following precau-
tions:
●Avoid contaminating the coolant
with foreign matter (such as
sand or dust, etc.).
●Do not use any coolant additive.

4938-1. Specifications
8
Vehicle specifications
Outside temperature
SAE 0W-16 is the best choice
for good fuel economy and good
starting in cold weather.
If SAE 0W-16 is not available,
SAE 0W-20 oil may be used.
However, it must be replaced
with SAE 0W-16 at the next oil
change.
Oil viscosity (0W-16 is explained
here as an example):
• The 0W in 0W-16 indicates the characteristic of the oil
which allows cold startability.
Oils with a lower value before the W allow for easier starting
of the engine in cold weather.
• The 16 in 0W-16 indicates the viscosity characteristic of the
oil when the oil is at high tem-
perature. An oil with a higher
viscosity (one with a higher
value) may be better suited if
the vehicle is operated at high
speeds, or under extreme
load conditions.
How to read oil container label:
API registered mark is added to
some oil containers to help you
select the oil you should use.
Cooling system
Capacity
Gasoline
engine10.5 qt. (9.9 L , 8.7 Imp. qt.)
Power con-
trol unit2.0 qt. (1.9 L, 1.7 Imp. qt.)
Coolant type
Use either of the following:
 “Toyota Super Long Life Coolant”
 Similar high-quality et hylene glycol-based
non-silicate, non -amine, non-nitrite, and
non-borate coolant with long-life hybrid organic
acid technology
Do not use pla in water alone.