Page 428 of 596
4287-3. Do-it-yourself maintenance
PRIUS c_U (OM52J11U)■
Location
The 12-volt battery is located
under the rear right seat.
■Removing the 12-volt battery cover
Remove the 2 clipsPush in the center part of
the clips
Remove the clips
Disengage the 3 clips and 3
guides on the back of the
cover and remove the 12-volt
battery cover. Guides
Clips
12-volt battery
1
1
2
2
1
2
Page 429 of 596
4297-3. Do-it-yourself maintenance
7
Maintenance and care
PRIUS c_U (OM52J11U)■
Exterior
Make sure that the 12-volt battery terminals are not corroded and
that there are no loose connecti
ons, cracks, or loose clamps.
Terminals
Hold-down clamp
■Installing the 12-volt battery cover Install the 12-volt battery
cover.Guides
Clips
Check if the clips and guides
on the back of the cover are
engaging properly if the cover
cannot be installed.
Install the 2 clips.Push out the center part of
the clips
Insert the clips
Push in the center part of
the clips
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flam-
mable and explosive. Therefore, observe the following precautions before
recharging:
●If recharging with the 12-volt battery installed on the vehicle, be sure to dis-
connect the ground cable.
● Make sure the “POWER” switch on the charger is off when connecting and
disconnecting the charger cables to the 12-volt battery.
1
2
1
1
2
2
1
2
3
Page 430 of 596

4307-3. Do-it-yourself maintenance
PRIUS c_U (OM52J11U)■
When disconnecting the 12- volt battery terminals
Always disconnect the negative (-) terminal first.
■ After recharging/reconnecting the 12-vo lt battery (vehicles with a smart
key system)
● Unlocking the doors using the smart key system may not be possible imme-
diately after reconnecting the 12-volt battery. If this happens, use the wire-
less remote control or the mechanical key to lock/unlock the doors.
● Start the hybrid system with the “POWER” switch in ACCESSORY mode.
The hybrid system may not start with the “POWER” switch turned off. How-
ever, the hybrid system will operat e normally 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 sta-
tus it was in before the 12-volt battery was disconnected. Make sure to turn
off the power before disconnect the 12-volt battery. Take extra care when
connecting the 12-volt battery if the “POWER” switch mode prior to dis-
charge is unknown.
If the system will not start even after multiple attempts, contact your Toyota
dealer.
WARNING
■ Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may
produce hydrogen gas which is flammable and explosive. To reduce the risk
of death or serious injury, take the following precautions while working on or
near the 12-volt battery:
● Do not cause sparks by touching 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 electrolyte.
● 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 insufficient ventila-
tion.
Page 431 of 596

4317-3. Do-it-yourself maintenance
7
Maintenance and care
PRIUS c_U (OM52J11U)
WARNING
■When disconnecting the 12- volt battery terminals
Always disconnect the negative (-) terminal first. If the positive (+) terminal
is disconnected first and touches a surrounding metal surface it may cause
sparks resulting in a fire or it may result in an electric shock, death or seri-
ous injury.
■ How to recharge th e 12-volt battery
Only perform a slow charge (3.5 A or less). The 12-volt battery may explode
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 with 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.
■ When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause
gas (hydrogen) to enter the passenger compartment, causing a fire or
explosion.
For replacement of the 12-volt battery, contact your Toyota dealer.
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while the hybrid system is operating.
Also, be sure all accessories are turned off.
Page 448 of 596
4487-3. Do-it-yourself maintenance
PRIUS c_U (OM52J11U)
●Flathead screwdriver
● Small flathead screwdriver
● Lithium battery CR2016 (vehicles without a smart key system), or
CR2032 (vehicles with 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.
Open the case cover using a
coin protected with tape etc.
and remove the depleted bat-
tery using a small flathead
screwdriver.
Insert a new battery with the “+”
terminal facing up.
Wireless remote control/electronic key battery
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery (vehicl es without a smart key system)
1
2
3
Page 449 of 596
4497-3. Do-it-yourself maintenance
7
Maintenance and care
PRIUS c_U (OM52J11U)
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
using a small flathead screw-
driver.
When removing the cover, the
electronic module may stick to the
cover and the battery may not be
visible. In this case, remove the
electronic module in order to
remove the battery.
Insert a new battery with the “+”
terminal facing up.
Replacing the battery (vehicles with a smart key system)
1
2
3
Page 450 of 596

4507-3. Do-it-yourself maintenance
PRIUS c_U (OM52J11U)
■Use a CR2016 (vehicles without a sm art key system) or CR2032 (vehicles
with a smart key system) 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 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 and other parts
These parts are small and if swallowed by a child, they can cause choking.
Keep away from children. Failure to do so could result in death or serious
injury.
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 control.
● Do not bend either of the battery terminals.
Page 465 of 596
465
8When trouble arises
PRIUS c_U (OM52J11U)8-1. Essential information
Emergency flashers .......... 466
If your vehicle has to be stopped in an
emergency ...................... 467
8-2. Steps to take in an emergency
If your vehicle needs to be towed ..................... 469
If you think something is wrong .......................... 476
If a warning light turns on or a warning buzzer
sounds ............................ 477
If a warning message is displayed ..................... 486
If you have a flat tire.......... 501
If the hybrid system will not start ..................... 514
If the electronic key does not operate
properly ........................... 516
If the vehicle 12-volt battery is discharged ....... 518
If your vehicle overheats ........................ 524
If the vehicle becomes stuck ............................... 528