2021 TOYOTA PRIUS PLUG-IN HYBRID key battery

7498-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
If the hybrid system will not start
One of the following may be the cause of the problem:
● The charging cable may be attached to the vehicle. (P. 165)
● The electronic key may not be functioning properly.* (P. 751)
● There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle. ( P. 1 1 0 )
● There may be a malfunction in the immobilizer system.* (P. 7 4 )
● There may be a malfunction in the shift control system.*
( P. 376, 729)
● The hybrid system may be malfunctioning due to an electrical prob-
lem such as electronic key battery depletion or a blown fuse. How-
ever, depending on the type of malfunction, an interim measure is
available to start the hybrid system. ( P. 750)
● There is a possibility that the temperature of the hybrid battery
(traction battery) is extremely low (approximately below -30 C
[-22 F]). (P. 110, 375)
*: 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. 755)
● The 12-volt battery terminal connections may be loose or corroded.
( P. 644)
Reasons for the hybrid system not starting vary depending on
the situation. Check the following and perform the appropriate
procedure:
The hybrid system will not start even though the correct starting
procedure is being followed. ( P. 373)
The interior lights and headlights are dim, or the horn does not
sound or sounds at a low volume.

7518-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
If the electronic key does not operate
properly
Use the mechanical key ( P. 279) in order to perform the following
operations:
Locks all the doors
Closes the windows (turn and
hold)*
Unlocks all the doors
Opens the windows (turn and
hold)*
*: This setting must be customized at
any authorized Toyota retailer or
Toyota authorized repairer, or any
reliable repairer. ( P. 782)
If communication between the electronic key and vehicle is inter-
rupted ( P. 296) or the electronic key cannot be used because the
battery is depleted, the smart entry & start system and wireless
remote control cannot be used. In such cases, the doors can be
opened and the hybrid system can be started by following the pro-
cedure below.
Locking and unlocking the doors
1
2
3
4

7548-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
■Stopping the hybrid system
Set the parking brake, shift the shift position to P and press the power switch
as you normally do when stopping the hybrid system.
■ Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the
electronic key battery be replaced imm ediately when the battery is depleted.
( P. 688)
■ Alarm (if equipped)
Using the mechanical key to lock the doors will not set the alarm system.
If a door is unlocked using the mechanical key when the alarm system is set,
the alarm may be triggered. ( P. 8 7 )
■ Changing power switch modes
Release the brake pedal and press the power switch in step above. The
hybrid system does not start and modes will be changed each time the switch
is pressed. ( P. 375)
■ When the electronic key does not work properly
● Make sure that the smart entry & start system has not been deactivated in
the customization setting. If it is off, turn the function on.
(Customizable features: P. 782)
● Check if battery-saving mode is set. If it is set, cancel the function.
( P. 295)
WARNING
■When using the mechanical key and operating the power windows
Operate the power window after checking to make sure that there is no pos-
sibility of any passenger having any of their body parts caught in the win-
dow.
Also, do not allow children to operate the mechanical key. It is possible for
children and other passengers to get caught in the power window.
3

7558-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
If the 12-volt battery is discharged
If you have a set of jumper (or booster) cables and a second vehicle
with a 12-volt battery, you can jump start your vehicle by following the
steps below.
Vehicles with an alarm
( P. 8 7 ) :
Confirm that the electronic key
is being carried.
When connecting the jumper (or
booster) cables, depending on the
situation, the alarm may activate
and doors locked. ( P. 89)
Open the hood. (P. 634)
Remove the engine cover.
Pull up the both ends of the cover
vertically.
The following procedures may be used to start the hybrid sys-
tem if the vehicle’s 12-volt battery is discharged.
You can also call any authorized Toyota retailer or Toyota autho-
rized repairer, or any reliable repairer.
1
2
3

7588-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
■When recharging or replacing the 12-volt battery
● In some cases, it may not be possible to unlock the doors using the smart
entry & start system when the 12-volt battery is discharged. Use the wire-
less remote control or the mechanical key to lock or unlock the doors.
● The hybrid system may not start on the first attempt after the 12-volt battery
has recharged but will start normally after the second attempt. This is not a
malfunction.
● It may be impossible to unlock the charging port lid or locking and unlocking
the charging connector immediately after the 12-volt battery is reconnected.
In this case, carry the electronic key on your person and operate the
charging port lid or charging connector lock switch again.
● The power switch mode is memorized by the vehicle. When the 12-volt bat-
tery is reconnected, the system will return to the mode it was in before the
12-volt battery was discharged. Before disconnecting the 12-volt battery,
turn the power switch off.
If you are unsure what mode the power switch was in before the 12-volt bat-
tery discharged, be especially careful when reconnecting the 12-volt battery.
● If the 12-volt battery discharges while the shift position is in P, it may not be
possible to shift the shift position to other positions. In this case, the vehicle
cannot be towed without lifting both front wheels because the front wheels
will be locked. ( P. 707)
■ When replacing the 12-volt battery
● Use a 12-volt battery that conforms to European regulations.
● Use a 12-volt battery that the case size is same as the previous one (LN1),
20 hour rate capacity (20HR) is equi valent (45Ah) or greater, and perfor-
mance rating (CCA) is equivalent (295A) or greater.
• If the sizes differ, the 12-volt battery cannot be properly secured.
• If the 20 hour rate capacity is low, even if the time period where the vehi-
cle is not used is a short time, the 12-volt battery may discharge and the
hybrid system may not be able to start.
● For details, consult any authorized Toyota retailer or Toyota authorized
repairer, or any reliable repairer.

7909-2. Customization
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
■Illumination (P. 591)
■Charge settings
■Maintenance system
FunctionDefault
settingCustomized
setting
Time elapsed before the inte-
rior lights turn off15 secondsOff
–OO 7.5 seconds
30 seconds
Operation after the power
switch is turned offOnOff––O
Operation when the doors are
unlockedOnOff––O
Operation when you approach
the vehicle with the electronic
key on your person
OnOff––O
Footwell lighting On Off – – O
Interior lights illumination con-
trolOn Off – – O
123
Charge scheduleSetting the charging schedule: P. 179
Charge currentChanging the upper limit of the charging cur-
rent: P. 150
Traction battery heaterSetting “Traction Battery Heater” on/off:
P. 155
Tire pressure warning
systemInitializing the tire pressure warning system:
P. 651

794What to do if... (Troubleshooting)
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
What to do if... (Troubleshooting)
●If you lose your mechanical keys, new genuine mechanical keys can be
made by any authorized Toyota retailer or Toyota authorized repairer, or
any reliable repairer. (P. 279)
●If you lose your electronic keys, the risk of vehicle theft increases signifi-
cantly. Contact any authorized Toyota retailer or Toyota authorized
repairer, or any reliable repairer immediately. (P. 282)
●Is the electronic key battery weak or depleted? (P. 688)
●Is the power switch in ON mode?
When locking the doors, turn the power switch off. (P. 375)
●Is the electronic key left inside the vehicle?
When locking the doors, make sure that you have the electronic key on
your person.
●The function may not operate properly due to the condition of the radio
wave. (P. 296)
●Is the child-protector lock set?
The rear door cannot be opened from inside the vehicle when the lock is
set. Open the rear door from outside and then unlock the child-protector
lock. (P. 286)
If you have a problem, check the following before contacting any
authorized Toyota retailer or Toyota authorized repairer, or any
reliable repairer.
The doors cannot be locked, unlocked, opened or closed
You lose your keys
The doors cannot be locked or unlocked
The rear door cannot be opened

795What to do if... (Troubleshooting)
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
●Did you press the power switch while firmly depressing the brake pedal?
( P. 373)
●Is the shift position in P? (P. 380)
●Is the electronic key anywhere detectable inside the vehicle? (P. 294)
●Is the electronic key battery weak or depleted?
In this case, the hybrid system can be started in a temporary way.
( P. 752)
●Is the 12-volt battery discharged? (P. 755)
●Is the window lock switch pressed?
The power windows except for the one at the driver’s seat cannot be oper-
ated if the window lock switch is pressed. ( P. 352)
●The auto power off function will be operated if the vehicle is left in
ACCESSORY or ON mode (the hybrid system is not operating) for a
period of time. ( P. 3 7 5 )
If you think something is wrong
The hybrid system does not start
The windows do not open or close by operating the power
window switches
The power switch is turned off automatically