2021 TOYOTA PRIUS key

PRIUS_OM_OM47E09U_(U)
5256-3. Do-it-yourself maintenance
6
Maintenance and care
■When opening the cover of the positive (+) battery terminal
■ Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flam-
mable and explosive. Therefore, observe the following precautio ns 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 connectin g and dis-
connecting 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 possi ble 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 do ors.
● Start the hybrid system with the power switch in ACCESSORY mode . The
hybrid system may not start with the power switch turned off. However, the
hybrid system will operate normally from the second attempt.
● The power switch mode is recorded by the vehicle. If the 12-vol t battery is
reconnected, the vehicle will return the power switch mode to t he status it
was in before the 12-volt battery was disconnected. Make sure t o turn off
the power before disconnect the 12-volt battery. Take extra car e when con-
necting the 12-volt battery if the power switch mode prior to d ischarge is
unknown.
If the system will not start even after multiple attempts at al l methods above,
contact your Toyota dealer. While pushing the portion shown in the
illustration from both sides, lift the end of
the cover up.

560
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
Electronic key batter y
●Flathead screwdriver
● Lithium battery CR2032
Release the lock and take out
the mechanical key.
Remove the cover.
Use a screwdriver of an appropri-
ate size. Forcedly prying may
cause the cover damaged.
To prevent damage to the key,
cover the tip of the screwdriver with
a rag.
Replace the battery with a n ew one if it is depleted.
You will need the following items:
Replacing the battery
1
2

PRIUS_OM_OM47E09U_(U)
5616-3. Do-it-yourself maintenance
6
Maintenance and care
Remove the depleted battery.
When removing the cover, if the
battery cannot be seen due to the
electronic key module attaching to
the upper cover, remove the elec-
tronic key module from the cover
so that the battery is visible as
shown in the illustration.
When removing the battery, use a
screwdriver of an appropriate size.
Insert a new battery with the “+” terminal facing up.
When installing, reverse the steps listed.
■Use a CR2032 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 the local laws.
■ If the electronic key battery is depleted
The following symptoms may occur:
●The smart key system and wireless remote control will not funct ion properly.
● The operational range will be reduced.
3
4

562
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
WARNING
■Battery precautions
Observe the following precautions.
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
swallowed, 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 p art of your
body, get emergency medical attention immediately.
■ To prevent battery explosion or leakage of flammable liquid or gas
● Replace the battery with a new battery of the same type. If a w rong type of
battery is used, it may explode.
● Do not expose batteries to extremely low pressure due to high altitude or
extremely high temperatures.
● Do not burn, break or cut a battery.
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.

579
PRIUS_OM_OM47E09U_(U)
7When trouble arises
7-1. Essential informationEmergency flashers .......... 580
If your vehicle has to be stopped in an
emergency ...................... 581
If the vehicle is trapped in rising water ..................... 582
7-2. Steps to take in an emergency
If your vehicle needs to be towed ......................... 584
If you think something is wrong .............................. 591
If a warning light turns on or a warning buzzer
sounds ............................ 592
If a warning message is displayed......................... 603
If you have a flat tire (vehicles without
spare tire)........................ 611
If you have a flat tire (vehicles with
spare tire)........................ 631
If the hybrid system will not start ........................... 645
If the electronic key does not operate properly ........ 647
If the 12-volt battery is discharged ...................... 650
If your vehicle overheats ... 656
If the vehicle becomes stuck ............................... 661

584
PRIUS_OM_OM47E09U_(U)
7-2. Steps to take in an emergency
If your vehicle needs to be towed
In the following situations, it is not possible to be towed by another
vehicle using cables or chains, as the front wheels may be lock ed due
to the parking lock. Contact your Toyota dealer or commercial towing
service.
● There is a malfunction in t he shift control system. (P. 249, 609)
● There is a malfunction in the immobilizer system. ( P. 95)
● There is a malfunction in the smart key system. (P. 647)
● The 12-volt battery is discharged. ( P. 6 5 0 )
The following may indicate a problem with your hybrid transmiss ion.
Contact your Toyota dealer or commercial towing service before tow-
ing.
● The hybrid system warning message is displayed and the vehicle
does not move.
● The vehicle makes an abnormal sound.
If towing is necessary, we recommend having your vehicle
towed by your Toyota dealer o r commercial towing service,
using a wheel-lift type t ruck or flatbed truck.
Use a safety chain system for all towing, and abide by all stat e/
provincial and local laws.
Situations when it is not possibl e to be towed by another vehicle
Situations when it is necessary to contact dealers before towing

6067-2. Steps to take in an emergency
PRIUS_OM_OM47E09U_(U)■
If “See Owner’s Manual” is shown
●If “Braking Power Low Stop in a Safe Place See Owner’s Manual” is shown,
this may be a malfunction. Immediately stop the vehicle in a sa fe place and
contact your Toyota dealer. Continuing to drive the vehicle may be danger-
ous.
● If “Engine Oil Pressure Low” is shown, this may be a malfunction. Immedi-
ately stop the vehicle in a safe place and contact your Toyota dealer.
● If the following messages are shown, there may be a malfunction . Immedi-
ately have the vehicle inspected by your Toyota dealer.
• “Hybrid System Malfunction”
• “Check Engine”
• “Hybrid Battery System Malfunction”
• “Accelerator System Malfunction”
• “Smart Key System Malfunction See Owner’s Manual”
■ If “Shift System Not A ctive Apply Parking Brake Securely While Parking
See Owner’s Manual” is shown
Indicates a temporary operation failure or malfunction in the shift control sys-
tem. Immediately have the vehicle inspected by your Toyota deal er.
When the message is shown, the hybrid system may not be started or the
shift position may not be changed normally. (Coping method: P. 609)
■ If “Shift System Malfunction A pply Parking Brake Securely While Park-
ing See Owner’s Manual” is shown
Indicates a malfunction in the shift control system. Immediatel y have the vehi-
cle inspected by your Toyota dealer.
When the message is shown, the hybrid system may not be started or the
shift position may not be changed normally. (Coping method: P. 609)
■ If “ Switch Malfunction Apply Par king Brake Securely While Parking
See Owner’s Manual” is shown
The P position switch may not operate. Immediately have the veh icle
inspected by your Toyota dealer.
When parking the vehicle, stop the vehicle on level ground and apply the
parking brake firmly.
■ If “Shift System Malfunction Shi fting Unavailable See Owner’s M anual”
is shown
Indicates a malfunction in the shift control system. Immediatel y have the vehi-
cle inspected by your Toyota dealer.
The shift position may not be shifted from P to other than P.
■ If “Shift System Malfunction S top in a Safe Place See Owner’s Manual”
is shown
Indicates a malfunction in the shift control system. Immediatel y have the vehi-
cle inspected by your Toyota dealer.
The shift position may not be changed. Stop the vehicle in a sa fe place.

645
PRIUS_OM_OM47E09U_(U)
7
When trouble arises
7-2. Steps to take in an emergency
If the hybrid system will not start
One of the following may be the cause of the problem:
● The electronic key may no t be functioning properly.
* ( P. 647)
● There may not be sufficient f uel in the vehicle’s tank.
Refuel the vehicle. ( P. 90)
● There may be a malfunction in the immobilizer system.
* ( P. 9 5 )
● There may be a malfunction i n the shift control system.
*
(  P. 249, 609)
● The hybrid system may be malfunc tioning due to an electrical prob-
lem such as electronic key battery depletion or a blown fuse. H ow-
ever, depending on the type of malfunction, an interim measure is
available to start the hybrid system. ( P. 646)
● There is a possibility that the t emperature of the hybrid battery
(traction battery) is extremely low (approximately below -22°F
[-30°C]). ( P. 90, 248)
*: It may not be possible to shift the shift position other than P.
One of the following may be the cause of the problem:
● The 12-volt battery may be discharged. ( P. 650)
● The 12-volt battery terminal connections may be loose or corrod ed.
(  P. 524)
Reasons for the hybrid system not starting vary depending on
the situation. Check the followi ng and perform the appropriate
procedure:
The hybrid system will not start even though the correct starting
procedure is being followed. ( P. 245)
The interior lights and headlights are dim, or the horn does no t
sound or sounds at a low volume.