2021 TOYOTA TUNDRA battery

4236-3. Do-it-yourself maintenance
6
Maintenance and care
■Before recharging
When recharging, the battery produces hydrogen gas which is flammable and
explosive. Therefore, observe the following before recharging:
●If recharging with the battery installed on the vehicle, be sur e to disconnect
the ground cable.
● Make sure the power switch on the charger is off when connectin g and dis-
connecting the charger cables to the battery.
■ After recharging/reconnecting the battery (vehicles with a smar t key sys-
tem)
The engine may not start. Follow the procedure below to initial ize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the engine.
● Unlocking the doors using the smart key system may not be possi ble imme-
diately after reconnecting the battery. If this happens, use the wireless
remote control or the mechanical key to lock/unlock the doors.
● Start the engine with the engine switch in ACC. The engine may not start
when the engine switch turned from off. However, the engine wil l operate
normally from the second attempt.
● The engine switch mode is recorded by the vehicle. If the batte ry is recon-
nected, the vehicle will return the engine switch mode to the s tatus it was in
before the battery was disconnected. Make sure to turn off the engine
before disconnect the battery. Take extra care when connecting the battery
if the engine switch mode prior to discharge is unknown.
If the system will not start even after multiple attempts, contact your Toyota
dealer.
1
2
3

4246-3. Do-it-yourself maintenance
WARNING
■Chemicals in the battery
Batteries contain poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the ri sk of death
or serious injury, take the following precautions while working on or near
battery:
● Do not cause sparks by touching the battery terminals with tool s.
● Do not smoke or light a match near the battery.
● Avoid contact with eyes, skin and clothes.
● Never inhale or swallow electrolyte.
● Wear protective safety glasses when working near the battery.
● Keep children away from the battery.
■ Where to safely charge the battery
Always charge the battery in an open area. Do not charge the battery in a
garage or closed room where there is insufficient ventilation.
■ How to recharge the battery
Only perform a slow charge (5 A or less). The battery may explod e if
charged at a quicker rate.
■ Emergency measures regarding electrolyte
● If electrolyte gets in your eyes
Flush your eyes with clean water for at least 15 minutes and get immedi-
ate medical attention. If possible, continue to apply water wit h a sponge or
cloth while traveling to the nearest medical facility.
● If electrolyte gets on your skin
Wash the affected area thoroughly. If you feel pain or burning, get medical
attention immediately.
● If electrolyte gets on your clothes
It can soak through clothing on to your skin. Immediately take off the cloth-
ing and follow the procedure above if necessary.
● If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergency medical attention
immediately.
NOTICE
■ When recharging the battery
Never recharge the battery while the engine is running. Also, b e sure all
accessories are turned off.

4516-3. Do-it-yourself maintenance
6
Maintenance and care
Wireless remote control/electronic key bat-
ter y

●Flathead screwdriver
● Small flathead screwdriver
● Lithium battery CR2016 (vehicles without a smart key system), o r
CR2032 (vehicles with a smart key system)
Vehicles without a smart key system
Remove the cover.
To prevent damage to the key,
cover the tip of the screwdriver with
a rag.
To prevent the buttons from being
disassembled, face the button sur-
face downward.
Remove the module.
: If equipped
Replace the battery with a n ew one if it is depleted.
You will need the following items:
Replacing the battery
1
2

4526-3. Do-it-yourself maintenance
Open the case cover using a
coin protected with tape, etc.,
and remove the depleted bat-
tery.
Insert a new battery with the “+”
terminal facing up.
Vehicles with a smart key system
Take out the mechanical key.
Remove the cover.
To prevent damage to the key,
cover the tip of the screwdriver with
a rag.
Remove the depleted battery.
Insert a new battery with the “+”ter-
minal facing up.
3
1
2
3

4536-3. Do-it-yourself maintenance
6
Maintenance and care
■Use a CR2016 (vehicles without a smart key system) or CR2032 (v ehicles
with a smart key system) lithium battery
● Batteries can be purchased at your Toyota dealer, local electri cal appliance
shops or camera stores.
● Replace only with the same or equivalent type recommended by the manu-
facturer.
● Dispose of used batteries according to local laws.
■ If the key battery is depleted
The following symptoms may occur:
●The smart key system (if equipped) and wireless remote control will not
function properly.
● The operational range will be reduced.
WARNING
■Removed battery a nd other parts
Keep away from children. These parts are small and if swallowed by a child,
they can cause choking. Failure to do so could result in death or serious
injury.
■ Certification for the lithium battery
CAUTION: RISK OF EXPLOSION IF BATTERY IS REPLACED BY AN
INCORRECT TYPE. DISPOSE OF USED BATTERIES ACCORDING TO
THE INSTRUCTIONS
NOTICE
■For normal operation after replacing the battery
Observe the following precautions to prevent accidents:
● Always work with dry hands.
Moisture may cause the battery to rust.
● Do not touch or move any other component inside the remote cont rol.
● Do not bend either of the battery terminals.

473
7When trouble arises
7-1. Essential informationEmergency flashers .......... 474
If your vehicle has to be stopped in
an emergency ................. 475
If the vehicle is trapped in rising water .................. 477 7-2. Steps to take in an emergency
If your vehicle needs to be towed ......................... 478
If you think something is wrong .............................. 483
Fuel pump shut off system ............................ 484
If a warning light turns on or a warning buzzer
sounds ............................ 485
If a warning message is displayed......................... 493
If you have a flat tire.......... 506
If the engine will not start ................................. 521
If the electronic key does not operate
properly (vehicles with
a smart key system) ........ 523
If the vehicle battery is discharged ...................... 525
If your vehicle overheats ... 529
If the vehicle becomes stuck ............................... 532

4747-1. Essential information
Emergency flashers
Press the switch.
All the turn signal lights will flash.
To turn them off, press the switch
once again.
■Emergency flashers
If the emergency flashers are used for a long time while the en gine is not
operating, the battery may discharge.
The emergency flashers are used to warn other drivers when the
vehicle has to be stopped in the road due to a breakdown, etc.

5037-2. Steps to take in an emergency
7
When trouble arises
OnceContin-
uous
An attempt was made to exit
the vehicle with the electronic
key and lock the doors without
first turning the engine switch
off when the shift lever was in
P.
Turn the engine switch
off and lock the doors
again.
Once
The electronic key is not
detected when an attempt is
made to start the engine.
Start the engine with the
electronic key present.
9 times
An attempt was made to drive
when the electronic key was
not inside the vehicle.
Confirm that the elec-
tronic key is inside the
vehicle.
Contin-
uous
An attempt was made to lock
the doors using the smart key
system while the electronic
key was still inside the vehicle.
Retrieve the electronic
key from the vehicle and
lock the doors again.
OnceContin-
uous
An attempt was made to lock
either front door by opening a
door and putting the inside
lock button into the lock posi-
tion, then closing the door with
the electronic key still inside
the vehicle.
Retrieve the electronic
key from the vehicle and
lock the doors again.
Once
The electronic key has a low
battery.
Replace the electronic
key battery. ( P. 451)
Interior
buzzerExterior buzzerWarning messageDetails/Actions
Turn Power OFF
Key Not Detected
(Flashes)
Key Not Detected
(Flashes)
Key Not Detected
(Flashes)
Key Detected in Vehicle
(Flashes)
Key Detectedin Vehicle
(Flashes)
Key Battery Low