2023 TOYOTA TUNDRA HYBRID cooling

4556-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
Light bulbs
(  P.490)
• Bulb with same
number and
wattage rating as
original
• Phillips-head screwdriver
• Wrench
Radiator and
condenser
(  P.461)

Tire inflation
pressure
( P.476)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.462)
• 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.
■When working on the engine
compartment
●Make sure that the “ACCES-
SORY” or “IGNITION ON” on
the multi-inform ation display
and the “READY” indicator are
both off.
●Keep hands, clothing and tools
away from the moving fan and
engine.
ItemsParts and tools●Be careful not to touch the
engine, inverter, 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
rags, in the engine compart-
ment.
●Do not smoke, cause sparks or
expose an open flame to fuel.
■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.461)
■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.

4576-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
Fuse boxes ( P.486)
Power control unit coolant reservoir ( P.460)
Intercooler coolant reservoir ( P.460)
Engine coolant reservoir ( P.460)
Engine oil filler cap ( P.458)
Engine oil level dipstick ( P.458)
Brake fluid reservoir ( P.461)
Engine radiator ( P.461)
Condenser ( P.461)
Electric cooling fans
Radiator cooling fan ( P.460)
Washer fluid tank ( P.462)
Intercooler radiators ( P.460)
Engine compar tment
Components

4616-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
“LOW” line
If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. ( P.535)
■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 temperature: -31°F [-
35°C])
Canada: “Toyota Super Long Life
Coolant” is a mixture of 55% coolant
and 45% deionized water.
(Minimum temperature: -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 coolant reser voir cap, inter-
coolant reservoir cap, 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, condenser
and intercooler radiators 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 dealer.
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN”
WARNING
■When the hybrid system is
hot
Do not remove the coolant reser-
voir 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,
condenser and inter-
cooler radiators
WARNING
■When the hybrid system is
hot
Do not touch the radiator, con-
denser or intercooler radiators or
condenser as they may be hot
and cause serious injuries, such
as burns.
Checking and adding the
brake fluid

4816-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
■Scheduled maintenance of the
air intake vents is necessary
when
In some situations such as when the
vehicle is used frequently or in
heavy traffic or dusty areas, the air
intake vents may need to be
cleaned more regularly.
For details, refer to the “Owner’s
Warranty Information Booklet” or
“Owner’s Manual Supplement”.
■Cleaning the air intake vent
Improper handling of the air intake
vent cover and filter may result in
damage to them. If you have any
concerns about cleaning the filter,
contact your Toyota dealer.
1 Turn the power switch off.
2 Remove the air intake vent
cover.
1 Pull the cover as shown in
the illustration to disengage
the 2 claws.
2 Pull the cover toward the side
of the vehicle to remove it.
3 Remove the filter from the air
intake vent cover.
If dust has accumula ted on the air
intake vent cover, remove the dust
Cleaning the hybrid
batter y (traction bat-
ter y) air intake vents
To prevent the fuel economy
from being affected, visually
inspect the hybrid battery
(traction battery) air intake
vents periodically for clogs.
If it is dusty or clogged or if
“Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual”
is displayed on the multi-
information display, clean
the air intake vent using the
following procedures:
NOTICE
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
displayed on the multi-infor-
mation display
Clean the air intake vent immedi-
ately.
If the vehicle is continuously
driven with the warning message
displayed, it may cause a mal-
function or output restriction of the
hybrid battery (traction battery).
Cleaning procedure

4836-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
ing it.
7 Install the air intake vent
cover.
1 Insert the tab of the cover as
shown in the illustration.
2 Push the cover to engage the
2 claws.
If “Maintenance Required for
Traction Battery Cooling Parts
See Owner’s Manual” was
displayed on the multi-infor-
mation display
8 Start the hybrid system and
check that the warning mes-
sage is no longer displayed.
It may take approximately 20 min-
utes after the hybrid system is
started until the warning message
disappears.
If the warning message does not
disappear after some time, have
the vehicle inspected by your Toy-
ota dealer.
■If the dust or sand on the filter
cannot be removed
It is recommended to use a vacuum
cleaner with plastic brushes.
WARNING
■When cleaning the air intake
vent
●Do not use water or other liq-
uids to clean the air intake vent.
If water is applied to the hybrid
battery (traction battery) or
other components, a malfunc-
tion or fire may occur.
●Before cleaning the air intake
vent, make sure to turn the
power switch off to stop the
hybrid system.
●Do not put a han d or leg in the
air intake vent. If it is caught in a
cooling fan, or if it touches a
high voltage part that results in
an electric shock, death or seri-
ous injuries may result.
●Do not touch the service plug
located near the air intake vent.
(  P. 7 7 )
NOTICE
■When cleaning the air intake
vent
Do not use an ai r blow gun, etc.
Dust may be blown out, possibly
causing a malfunction or output
restriction of the hybrid battery
(traction battery).

5127-2. Steps to take in an emergency
Owners Manual_USA_M0C052_entems such as PCS (Pre-Collision
system) or the dynamic radar cruise
control with full-speed range is oper-
ating. If a warning message is
shown, be sure to decelerate the
vehicle or follow an instruction
shown on the multi
-information dis-
play.
A warning message is shown when
Brake Override System operates.
(  P.172)
A warning message is shown when
Drive-Start Control ( P.177) or
Parking Support Brake ( P.287)
operates. Follow the instructions on
the multi-information display.
●If a message about an operation
of the power switch is displayed
An instruction for operation of the
power switch is shown when the
incorrect procedure for starting the
hybrid system is performed or the
power switch is operated incorrectly.
Follow the instructions shown on the
multi-information display to operate
the power switch again.
●If a message abou t a shift lever
operation is displayed
To prevent the shift lever from being
operated incorrectly or the vehicle
from moving unexpectedly, a mes-
sage that requires shifting the shift
lever may be sho wn on the multi-
information display . In that case, fol-
low the instruction of the message
and shift the shift lever.
●If a message or image about an
open/close state of a part or
replenishment of a consumable is
displayed
Confirm the part indicated by the
multi-information display or a warn-
ing light, and then perform the cop-
ing method such as closing the open door or replenishing a con-
sumable.
■If a message that indicates the
need for visiting your Toyota
dealer is displayed
The system or part shown on the
multi-information di splay is malfunc-
tioning. Have the vehicle inspected
by your Toyota dealer immediately.
■If a message that indicates the
need for referring to Owner’s
Manual is displayed
●If “Engine Coolant Temp High
Stop in a Safe Place See Owner’s
Manual” is shown, follow the
instructions ( P.535).
●If the following messages are
shown, there may be a malfunc-
tion.
Immediately stop the vehicle in a
safe place and contact your Toy-
ota dealer. Continuing to drive the
vehicle may be dangerous.
• “Hybrid System Malfunction”
• “Check Engine”
• “Traction battery system malfunc- tion”
• “Accelerator System Malfunction”
• “Hybrid System Stopped”
• “Smart Key System Malfunction See Owner’s Manual”
●If the following messages are
shown, there may be a malfunc-
tion.
Immediately have the vehicle
inspected by your Toyota dealer.
• “Oil Pressure Low Stop in a Safe Place See Owner’s Manual”
• “Braking Power Low Stop in a
Safe Place See Owner’s Manual”
●If “Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is shown, the fil-
ter may be clogged, the air intake
vents may be blo cked, or there
may be a gap in the duct. There-
fore, perform the following correc-
tion procedure.
Cleaning the hybrid battery (traction
battery) air intake vents ( P.481)

5347-2. Steps to take in an emergency
Owners Manual_USA_M0C052_en
WARNING
●After replacing, securely attach
the exhaust hose and exhaust
hole plug to the exhaust hole of
the replaced 12-volt battery. If
not properly installed, gases
(hydrogen) may leak into the
vehicle interior, and there is the
possible danger of the gas ignit-
ing and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper
cables, ensure that they do not
become entangled in the cooling
fan.

5357-2. Steps to take in an emergency
Owners Manual_USA_M0C052_en
7
When trouble arises
■If the engine coolant tem-
perature gauge enters the
red zone or “Engine Cool-
ant Temp High Stop in a
Safe Place See Owner’s
Manual” is shown on the
multi-information 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, engine
radiator core (radiator) and
intercooler radiator core
(radiator) for any leaks.
If a large amount of coolant leaks,
immediately cont act your Toyota dealer.
Cooling fan
Radiator
Intercooler radiators
4 The coolant level is satisfac-
tory if it is between the “F” or
“FULL” and “L” or “LOW”
lines on the reservoir.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
The needle of the engine coolant temperature gauge ( P.91)
enters the red zone or a loss of engine (hybrid system) power i s
experienced. (For example, the vehicle speed does not
increase.)
 “Engine Coolant Temp High Stop in a Safe Place See Owner’s
Manual” is shown on the multi-information display.
Steam comes out from under the hood.
Correction procedures