2023 TOYOTA TUNDRA HYBRID key battery

4546-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6-3.Do-it-yourself maintenance
Do-it-yourself ser vice
precautions
If you perform maintenance
by yourself, be sure to fol-
low the correct procedure
as given in these sections.
Maintenance
ItemsParts and tools
12-volt battery
condition
( P.463)
•Grease
•Warm water
• Baking soda
• Distilled water
• Flat-head screw-
driver or
mechanical key
( P. 1 1 0 )
• Conventional wrench (for ter-
minal clamp
bolts)
Brake fluid
level ( P.461)
• FMVSS No.116
DOT 3 or SAE
J1703 brake fluid
FMVSS No.116
DOT 4 or SAE
J1704 brake fluid
• Rag or paper towel
• Funnel (used only for adding
brake fluid)
Engine/inter-
cooler/power
control unit
coolant level
( P.460)
• “Toyota Super
Long Life Cool-
ant” or a similar
high quality eth-
ylene glycol-
based non-sili-
cate, nonamine,
non-nitrite and
non-borate cool-
ant with longlife
hybrid organic
acid technology
For the U.S.A.:
“Toyota Super
Long Life Cool-
ant” is pre-mixed
with 50% cool-
ant and 50%
deionized water.
For Canada:
“Toyota Super
Long Life Cool-
ant” is pre-mixed
with 55% cool-
ant and 45%
deionized water.
• Funnel (used only for adding
coolant)
Engine oil level
( P.458)
• “Toyota Genuine
Motor Oil” or
equivalent
• Rag or paper towel
• Funnel (used only for adding
engine oil)
Fuses
( P.486)• Fuse with same
amperage rating
as original
ItemsParts and tools

4636-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
The 12-volt battery is located in
the left-hand side of the rear
seat under.
1 Raising the bottom cushion.
( P.135)
2 Remove the battery cover.
Use the flat-head screwdriver or
mechanical key ( P.110).
■Before recharging
When recharging, the 12-volt bat-
tery produces hydrogen gas which
is flammable and explosive. There-
fore, observe the following precau-
tions before recharging:
●If recharging with the 12-volt bat-
NOTICE
■Do not use any fluid other
than washer fluid
Do not use soapy water or anti-
freeze instead of washer fluid.
Doing so may cause streaking on
the vehicle’s painted surfaces, as
well as damaging the pump lead-
ing to problems of the washer
fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as
necessary.
Refer to the freezing tempera-
tures listed on the label of the
washer fluid bottle.
12-volt batter y
Location
Removing the 12-volt bat-
tery cover

4646-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_entery installed on the vehicle, be
sure to disconnect the ground
cable.
●Make sure the power switch on
charger is off when connecting
and disconnecting the charger
cables to the 12-volt battery.
■After recharging/reconnecting
the 12-volt battery
●Unlocking the doors using the
smart key system may not be pos-
sible immediately after reconnect-
ing the 12-volt battery. If this
happens, use the wireless remote
control or the mechanical key to
lock/unlock the doors.
●Start the hybrid system with the
power switch in ACC. The hybrid
system may not start with the
power switch turned off. However,
the hybrid system will operate nor-
mally from the second attempt.
●The power switch mode is
recorded by the vehicle. If the 12-
volt battery is
reconnected, the
vehicle will return the power
switch mode to the status it was in
before the 12-volt battery was dis-
connected. Make sure to turn off
the power switch before discon-
necting the 12-volt battery. Take
extra care when connecting the
12-volt battery if the power switch
mode prior to discharge is
unknown.
●When the 12-volt b attery is recon-
nected, start the hybrid system,
depress the brake pedal, and con-
firm that it is possible to shift into
each shift position.
If the system will not start even after
multiple attempts, contact your Toy-
ota dealer.
WARNING
■Chemicals in the 12-volt bat-
tery
The 12-volt battery contains poi-
sonous and corrosive sulfuric acid
and may produce hydrogen gas
which is flammable and explosive.
To reduce the risk of death or seri-
ous injury, take the following pre-
cautions while working on or near
the 12-volt battery:
●Do not cause sparks by touch-
ing the 12-volt battery terminals
with tools.
●Do not smoke or light a match
near the 12-volt battery.
●Avoid contact with eyes, skin
and clothes.
●Never inhale or swallow electro-
lyte.
●Wear protective safety glasses
when working near the 12-volt
battery.
●Keep children away from the
12-volt battery.
■Where to safely charge the
12-volt battery
Always charge the 12-volt battery
in an open area. Do not charge
the 12-volt battery in a garage or
closed room where there is insuf-
ficient ventilation.
■Emergency measures regard-
ing electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean
water for at least 15 minutes
and get immediate medical
attention. If possible, continue
to apply water with a sponge or
cloth while traveling to the near-
est medical facility.

4846-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
■If the electronic key battery is
depleted
The following symptoms may occur:
●The smart key system and wire-
less remote control will not func-
tion properly.
●The operational range will be
reduced.
 Flathead screwdriver
 Small flathead screwdriver
 Lithium battery CR2450
■Use a CR2450 lithium battery
●Batteries can be purchased at
your Toyota dealer, local electrical
appliance shops or camera stores.
●Replace only with the same or
equivalent type recommended by
the manufacturer.
●Dispose of used batteries accord-
ing to local laws.
NOTICE
■To prevent damage to the
vehicle
Observe the following precau-
tions:
●Do not allow water or foreign
matter to enter t he air intake
vent.
●Make sure to reinstall the filter
and cover to their original posi-
tions after cleaning.
●Do not install anything to the air
intake vent other than the exclu-
sive filter for this vehicle or use
the vehicle without the filter
installed.
■To prevent damage to the fil-
ter
Observe the following precau-
tions.
If the filter is damaged, have it
replaced with a new filter by your
Toyota dealer.
●Do not use an air blow gun, etc.
●Do not press hard a vacuum
cleaner, etc. against the filter.
●Do not use a hard brush, such
as a metal brush.
●Do not break the fold of the fil-
t er.
Electronic key batter y
Replace the battery with a
new one if it is depleted.
As the key may be damaged
if the following procedure is
not performed properly, it is
recommended that key bat-
tery replacement be per-
formed by your Toyota
dealer.
Items to prepare

4856-3. Do-it-yourself maintenance
Owners Manual_USA_M0C052_en
6
Maintenance and care
1 Take out the mechanical key.
2 Remove the cover.
To prevent damage to the key,
cover the tip of the flathead screw-
driver with a tape.
3Remove the depleted battery.
Insert a new battery with the “+” ter-
minal facing up.
Replacing the batteryWARNING
■Removed battery and other
parts
These parts are small and if swal-
lowed by a child, they can cause
choking. Keep away from chil-
dren. Failure to do so could result
in death or serious injury.
■Battery precautions
Observe the following precau-
tions.
Failure to do so may result in
death or serious injury.
●Do not swallow the battery.
Doing so may cause chemical
burns.
●A coin battery or button battery
is used in the electronic key. If a
battery is swa llowed, it may
cause severe chemical burns in
as little as 2 hours and may
result in death or serious injury.
●Keep away new and removed
batteries from children.
●If the cover cannot be firmly
closed, stop using the electronic
key and stow the key in the
place where children cannot
reach, and then contact your
Toyota dealer.
●If you accidentally swallow a
battery or put a battery into a
part of your b ody, get emer-
gency medical attention imme-
diately.
■To prevent battery explosion
or leakage of flammable liq-
uid or gas
●Replace the battery with a new
battery of the same type. If a
wrong type of battery is used, it
may explode.

493
Owners Manual_USA_M0C052_en
7
7
When trouble arises
When trouble arises
7-1. Essential informationEmergency flashers .... 494
If your vehicle has to be stopped in an emergency.................................. 494
If the vehicle is submerged or water on the road is ris-
ing ............................. 495
7-2. Steps to take in an emer- gency
If your vehicle needs to be towed......................... 497
If you think something is wrong ........................ 499
If a warning light turns on or a warning buzzer sounds
.................................. 501
If a warning message is dis- played........................ 511
If you have a flat tire.... 515
If the hybrid system will not start ........................... 524
If you lose your keys ... 526
If the fuel door cannot be opened ...................... 526
If the electronic key does not operate properly .. 527
If the vehicle 12-volt battery is discharged ............. 529
If your vehicle overheats .................................. 535
If the vehicle becomes stuck .................................. 538

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)

5247-2. Steps to take in an emergency
Owners Manual_USA_M0C052_en
One of the following may be the
cause of the problem:
The electronic key may not be
functioning properly.
( P.527)
 There may not be sufficient
fuel in the vehicle’s tank.
Refuel the vehicle.
 There may be a malfunction
in the immobilizer system.
( P.81)
 The hybrid system may be
malfunctioning due to an elec-
trical problem such as elec-
tronic key battery depletion or
a blown fuse. However,
depending on the type of mal-
function, an interim measure
is available to start the hybrid
system. ( P.525)
 The temperature of the hybrid
battery (traction battery) may
be extremely low (below
NOTICE
■To avoid damage to the tire
pressure warning valves and
transmitters
When a tire is repaired with liquid
sealants, the tire pressure warn-
ing valve and transmitter may not
operate properly. If a liquid seal-
ant is used, contact your Toyota
dealer or other qualified service
shop as soon as possible. Make
sure to replace the tire pressure
warning valve and transmitter
when replaci ng the tire. (P.470)
If the hybrid system
will not star t
Reasons for the hybrid sys-
tem not starting vary
depending on the situation.
Check the following and
perform the appropriate
procedure:
The hybrid system will not
start even though the cor-
rect starting procedure is
being followed. ( P.195)