cooling TOYOTA TUNDRA HYBRID 2023 Owners Manual

751-4. Hybrid system
Owners Manual_USA_M0C052_en
1
For safety and security
■Charging the 1 2-volt battery
 P. 5 3 1
■After the 12-volt battery has dis-
charged or when the terminal
has been removed and installed
during exchange, etc.
The gasoline engine may not stop
even if the vehicle is being driven by
the hybrid battery (traction battery).
If this continues for a few days, con-
tact your Toyota dealer.
■Sounds and vibrations specific
to a Hybrid Electric Vehicle
There may be no engine sound or
vibration even though the vehicle is
able to move with the “READY” indi-
cator is illuminated. For safety, apply
the parking brake and make sure to
shift the shift lever to P when
parked.
The following sounds or vibrations
may occur when the hybrid system
is operating and are not a malfunc-
tion:
●Motor sounds may be heard from
the engine compartment.
●Sounds may be heard from the
hybrid battery (traction battery)
under the rear seats when the
hybrid system starts or stops.
●Relay operating sounds such as a
snap or soft clank will be emitted
from the hybrid battery (traction
battery), under the rear seats,
when the hybrid system is started
or stopped.
●Sounds may be heard from the
transmission when the gasoline
engine starts or stops, when driv-
ing at low speeds, or during idling.
●Engine sounds may be heard
when accelerating sharply.
●Sounds may be heard due to
regenerative braking when the
brake pedal is dep ressed or as
the accelerator pedal is released.
●Vibration may be felt when the
gasoline engine starts or stops.
●Cooling fan sounds may be heard
from the air intake vents on the
side of the lower part of the rear
seat.
■Maintenance, repair, recycling,
and disposal
Contact your Toyota dealer regard-
ing maintenance, repair, recycling
and disposal. Do n ot dispose of the
vehicle yourself.
When the gasoline engine is off
while driving, a sound is pro-
duced to warn pedestrians, peo-
ple riding bicycles or other
people and vehicles in the sur-
rounding area that the vehicle is
approaching. The pitch of the
sound adjusts according to vehi-
cle speed. When vehicle speed
is approximately 22 mph (35
km/h) or more, the warning sys-
tem turns off.
■Acoustic vehicle alerting sys-
tem
In the following cases, the acoustic
vehicle alerting system sound may
be difficult for pedestrians, people
riding bicycles or other people and
vehicles in the surrounding area to
hear:
●When there is a lot of noise in the
vicinity
●When it is raining or during strong
winds
Acoustic vehicle alerting
system

791-4. Hybrid system
Owners Manual_USA_M0C052_en
1
For safety and security
There are air intake vents under
the rear seat for the purpose of
cooling the hybrid battery (trac-
tion battery).
If the vents are blocked, it may
interfere with the cooling of the
hybrid battery (traction battery).
If input/output of the hybrid battery
(traction battery) becomes limited
and the distance that the vehicle
can be driven using the electric
motor (traction motor) is reduced,
the fuel economy may be reduced.
When a certain level of impact is
detected by the impact sensor,
the emergency shut off system
blocks the high voltage current
and stops the fuel pump to mini-
mize the risk of electrocution
and fuel leakage. If the emer-
gency shut off system activates,
your vehicle will not restart. To
restart the hybrid system, con-
tact your Toyota dealer.
A message is automatically dis-
played when a malfunction
occurs in the hybrid system or
an improper operation is
attempted.
NOTICE
■Hybrid battery (traction bat-
tery)
Do not carry large amounts of
water such as water cooler bottles
in the vehicle. If water spills onto
the hybrid battery (traction bat-
tery), the batte ry may be dam-
aged. Have the vehicle inspected
by your Toyota dealer.
Hybrid battery (traction
battery) air intake vents
NOTICE
■Hybrid battery (traction bat-
tery) air intake vents
●Make sure not to block the air
intake vents with anything, such
as a seat cover, plastic cover, or
luggage.
The input/output of the hybrid
battery (traction battery) may be
restricted, leading to a reduction
in hybrid battery (traction bat-
tery) output and a malfunction.
●Periodically clean the air intake
vents to prevent them from clog-
ging. ( P.481)
●Do not get water or foreign
materials in the air intake vents
as this may cause a short circuit
and damage the hybrid battery
(traction battery).
Emergency shut off sys-
tem
Hybrid warning message

3584-5. Using the driving support systems
Owners Manual_USA_M0C052_enturn on.
2
Select the driving modes on
the multi-information display
while turning the mode select
switch left and right.
Vehicles without Adaptive
Variable Suspension system
Multi-information display
• “NORMAL” mode
Provides an optimal balance of fuel
economy, quietness, and dynamic
performance. Suitable for city driv-
ing.
•“ECO” mode
Helps the driver a ccelerate in an
eco-friendly manner and improve
fuel economy through moderate
throttle characteri stics and by con- trolling the operation of the air con-
ditioning system (heating/cooling).
The “ECO” indicator comes on.
• “SPORT” mode
Assists acceleration response by
controlling the transmission, engine
and steering. Suitable for when pre-
cise handling is desirable, for
example when driving on mountain
roads. The “SPORT” indicator
comes on.
Vehicles with Adaptive Vari-
able Suspension system
Multi-information display
• “NORMAL” mode
Provides an optimal balance of fuel
economy, quietness, and dynamic
performance. Suitable for city driv-
ing.
• “COMFORT” mode
By controlling the suspension, rid-
ing comfort is further enhanced.
Suitable for city driving. The “COM-
FORT” indicator comes on.
• “ECO” mode
Helps the driver accelerate in an
eco-friendly manner and improve

3594-5. Using the driving support systems
Owners Manual_USA_M0C052_en
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Driving
fuel economy through moderate
throttle characteri stics and by con-
trolling the operation of the air con-
ditioning system (heating/cooling).
The “ECO” indicator comes on.
• “SPORT S” mode
Assists accelerati on response by
controlling the transmission, engine
and steering. Suitable for when pre-
cise handling is desirable, for
example when driving on mountain
roads. The “SPORT S” indicator
comes on.
• “SPORT S+” mode
Helps to ensure th e controllability
and stability of the vehicle by inte-
grally controlling the steering wheel
and suspensions as well as the
transmission and engine, making it
suitable for sporty driving. The
“SPORT S+” indicator comes on.
• “CUSTOM” mode
Allows you to drive with the power
train, chassis and air conditioning
system functions set to your pre-
ferred settings. Custom mode set-
tings can only be changed on the
drive mode customization display of
multimedia system. The “CUSTOM”
indicator comes on.
■The driving mode select switch
can be operated when
The front-wheel dri ve control switch
is in “2H” and “4H”.
■Operation of the air condition-
ing system in Eco mode
Eco mode controls the heating/cool-
ing operations and fan speed of the
air conditioning system to enhance
fuel efficiency. To improve air condi-
tioning performance, perform the
following operations:
●Adjust the fan speed ( P.400)
●Turn off Eco drive mode ( P.358)
■Automatic deactivation of driv-
ing modes:
Driving mode is deactivated or the
driving mode will be changed to nor-
mal mode in the following condi-
tions:
●After turning the power switch off
and then turning it to on
●When the front-wheel drive control
switch is in “4L” (4WD models
only)
●When the Multi-terrain Select is
turned on (if equipped)
●When the Downhill assist control
system is turned on (if equipped)
●When the “TOW HAUL” mode or
“TOW+” mode is turned on (if
equipped)
■Customization
The Custom mode can be changed.
(Customizable features: P.570)

3894-6. Driving tips
Owners Manual_USA_M0C052_en
4
Driving
4-6.Driving tips
When using Eco drive mode, the
torque corresponding to the
accelerator pedal depression
amount can be generated more
smoothly than it is in normal
conditions. In addition, the oper-
ation of the air conditioning sys-
tem (heating/cooling) will be
minimized, improving the fuel
economy. ( P.358)
The Eco-friendly driving is pos-
sible by keeping the indicate of
Hybrid System Indicator within
Eco area. ( P.97)
Shift the shift lever to D when
stopped at a traffic light, or driv-
ing in heavy traffic etc. Shift the
shift lever to P when parking.
When using the N, there is no
positive effect on fuel consump-
tion. When using the air condi-
tioning system, etc., the hybrid
battery (traction battery) power
is consumed. 
Drive your vehicle smoothly.
Avoid abrupt acceleration and
deceleration. Gradual accel-
eration and deceleration will
make more effective use of
the electric motor (traction
motor) without having to use
gasoline engine power.
 Avoid repeated acceleration.
Repeated acceleration con-
sumes hybrid battery (trac-
tion battery) power, resulting
in poor fuel consumption. Bat-
tery power can be restored by
driving with the accelerator
pedal slightly released.
Make sure to operate the brakes
gently and in a timely manner. A
greater amount of electrical
energy can be regenerated
when slowing down.
Repeated acceleration and
deceleration, as well as long
waits at traffic lights, will lead to
bad fuel economy. Check traffic
reports before leaving and avoid
delays as much as possible.
When driving in a traffic jam,
gently release the brake pedal
to allow the vehicle to move for-
ward slightly while avoiding
Hybrid Electric Vehi-
cle driving tips
For economical and ecolog-
ical driving, pay attention to
the following points:
Using Eco drive mode
Use of Hybrid System
Indicator
Shift lever operation
Accelerator pedal/brake
pedal operation
When braking
Delays

4015-1. Using the air conditioning system and defogger
Owners Manual_USA_M0C052_en
5
Interior features
fan speed and downwards to
decrease the fan speed.
Press the “OFF” switch to turn the
fan off.
■Change the airflow mode
Operate the air flow mode con-
trol toggle
The airflow mode changes as fol-
lows each time the toggle is oper-
ate.
1 Air flows to the upper body.
2 Air flows to the upper body
and feet.
3 Air flows to the feet.
4 Air flows to the feet and the
windshield defogger oper-
ates.
■Switching between outside
air and recirculated air
modes
Press the outside/recirculated
air mode switch.
The mode switches between
outside air mode and recircu-
lated air mode each time the switch is operated.
When recirculated air mode is
selected, the indicator illumi-
nates on the outside/recircu-
lated air mode switch.
■Set cooling and dehumidifi-
cation function
Press the “A/C” switch.
When the function is on, “A/C ON”
indicator will illumi nate. When the
function is off, “A/ C OFF” indicator
will illuminate.
■Defogging the windshield
Defoggers are used to defog the
windshield and front side win-
dows.
Press the windshield defogger
switch.
Press the outside air mode switch if
the recirculated air mode is used. (It
may switch automatically.)
To defog the windshield and the
side windows quickly, turn the air
flow and temperature up.
To return to the previous mode,
press the windshield defogger
switch again when the windshield is
defogged.
When the windshield defogger
switch is on, the indicator illumi-
nates on the windshield defogger
switch.
■Defogging the rear window
and outside rear view mir-
rors
Defoggers are used to defog the
rear window and to remove rain-
drops, dew and frost from the

4025-1. Using the air conditioning system and defogger
Owners Manual_USA_M0C052_en
outside rear view mirrors.
Press the rear window and out-
side rear view mirror defoggers
switch.
The defoggers will automatically
turn off after 15 minutes.
When the rear window and outside
rear view mirror defoggers switch is
on, the indicator illuminates on the
rear window and ou tside rear view
mirror defoggers switch.
■When the outside temperature
exceeds 75°F (24°C) and the air
conditioning system is on
●In order to reduce the air condi-
tioning power consumption, the air
conditioning system may switch to
recirculated air mode automati-
cally.
This may also reduce fuel con-
sumption.
●Recirculated air mode is selected
as a default mode when the power
switch is turned to ON.
It is possible to switch to outside air
mode at any time by pressing the
outside air mode switch.
■Fogging up of the windows
●The windows will easily fog up
when the humidity in the vehicle is
high. Turning the cooling and
dehumidification function on will
dehumidify the air from the outlets
and defog the windshield effec-
tively.
●If you turn the cooling and dehu-
midification function off, the win-
dows may fog up more easily.
●The windows may fog up if the
recirculated air mode is used.
■When driving on dusty roads
Close all windows. If dust thrown up
by the vehicle is still drawn into the
vehicle after closing the windows, it
is recommended that the air intake mode be set to outside air mode and
the fan speed to a
ny setting except
off.
■Outside/recirculated air mode
●Setting to the recirculated air
mode temporarily is recom-
mended in preventing dirty air
from entering the vehicle interior
and helping to c ool the vehicle
when the outside air temperature
is high.
●Outside/recirculated air mode may
automatically switch depending on
the temperature setting or the
inside temperature.
■When the outside temperature
falls to nearly 32°F (0°C)
The dehumidification function may
not operate even when “A/C” switch
is pressed.
■Ventilation and air conditioning
odors
●To let fresh air in, set the air condi-
tioning system to the outside air
mode.
●During use, various odors from
inside and outside the vehicle may
enter into and accumulate in the
air conditioning system. This may
then cause odor to be emitted
from the vents.
●In order to suppr ess odors that
occur when the air conditioning
system starts, the air flow mode
may change to blow air to the feet
or air may stop blowing for a short
period of time immediately after
the air conditioning system is
started in automatic mode.
●When parking, the system auto-
matically switches to outside air
mode to encourage better air cir-
culation throughout the vehicle,
helping to reduce odors that occur
when starting the vehicle.
■Air conditioning filter
 P.479

4305-4. Using the other interior features
Owners Manual_USA_M0C052_en
WARNING
●Do not use devices which pro-
duce steam while the windows
are closed. Doing so may cause
the windows to fog up, reducing
visibility and making it difficult to
drive safely. Also, the steam
may damage or negatively
affect other devices. If the
device must be used, stop the
vehicle and open the windows
before use.
●Do not use damaged electronic
devices. The power supply
function may not be able to be
used.
●Do not disconnect the plug of a
device while your hands are wet
or insert a pin or other object
into the pow er outlet. Also, if a
liquid or snow is on the power
outlet, dry the outlet before
using it.
●Do not attempt to modify, disas-
semble or repair a power outlet.
For information on repairs, con-
tact your Toyota dealer.
●Do not let children touch the
power outlets.
●Keep the power outlets free of
dust and foreign matter. Also,
regularly clean the power outlet.
●If the plug of a device fits
loosely in a pow er outlet, even
though it is fully inserted,
replace the power outlet. For
information on replacement,
contact your Toyota dealer.
■Using the power outlets while
parked or stopped
Observe the following precau-
tions.
Failure to do so may lead to an
accident, possibly resulting in
death or serious injury.
●Do not leave the vehicle unat-
tended while the hybrid system
is operating and a device is con-
nected to a power outlet.
●Do not place luggage or get
near the vicinit y of the tailpipe.
●Make sure that the hood is
closed. Do not put your head or
hands anywhere inside the
engine room, as the cooling
fans may operate suddenly. If
too close, hands and clothing
(especially a tie, scarf, etc.) may
get caught in a fan.
●Do not stop the vehicle near
objects which burn easily.
●Install and use appropriately
related devices to make air sup-
ply and exhaust ventilation pos-
sible in places where ventilation
is bad, such as within garages,
and places where the vehicle is
surrounded (places where snow
accumulates).
●Do not use in places where ven-
tilation is bad, such as within
garages where there are no air
supply and exhaust ventilation
devices, and places where the
vehicle is surrounded (places
where snow accumulates, etc.).
●Do not use the power outlets if
the vehicle has a vehicle cover
installed.
●Do not sleep in the vehicle while
using devices such as an elec-
tric heater.
■Devices to be connected
●Read the instruction manual
included with the electronic
device being used and observe
the precautions that are stated
regarding the product.
●Do not use when the power plug
or electronic device are dam-
aged.

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