change key battery Lexus IS350 2021 Owner's Manual / LEXUS 2021 IS 300, IS 350 OWNER'S MANUAL (OM53E98U)

621-4. Theft deterrent system
■Items to check before locking the
vehicle
To prevent unexpected triggering of
the alarm and vehicle theft, make sure
of the following:
 Nobody is in the vehicle.
 The windows and moon roof (if
equipped) are closed before the
alarm is set.
 No valuables or other personal
items are left in the vehicle.
■Setting
Close the doors, trunk and hood, and
lock all the doors. The system will be
set automatically after 30 seconds.
The indicator light changes from being on
to flashing when the system is set.
■Deactivating or stopping
Do one of the following to deactivate
or stop the alarm:
 Unlock the doors.
 Open the trunk.
 Turn the engine switch to ACCES-
SORY or IGNITION ON mode, or
start the engine. (The alarm will be
deactivated or stopped after a few
seconds.)
■System maintenance
The vehicle has a maintenance-free type
alarm system.
■Triggering of the alarm
The alarm may be triggered in the following
situations:
(Stopping the alarm deactivates the alarm
system.)
●A person inside the vehicle opens a door
or the trunk or hood, or unlocks the vehi-
cle.
●The battery is recharged or replaced
when the vehicle is locked. ( P.363)
Alarm
The alarm uses light and sound to
give an alert when an intrusion is
detected.
The alarm is triggered in the follow-
ing situations when the alarm is set:
 A locked door or trunk is
unlocked or opened in any way
other than using the entry func-
tion, wireless remote control or
mechanical key. (The doors will
lock again automatically.)
 The hood is opened.
Setting/deactivating/stopping
the alarm system

933-2. Opening, closing and locking the doors and trunk
3
Before driving
To prevent unintended triggering of the
alarm, unlock the doors using the wireless
remote control and open and close a door
once after the settings have been changed.
(If a door is not opened within 60 seconds
after is pressed, the doors will be
locked again and the alarm will automati-
cally be set.)
In a case that the alarm is triggered, imme-
diately stop the alarm. (P.62)
■Impact detection door lock release sys-
tem
In the event that the vehicle is subject to a
strong impact, all the doors are unlocked.
Depending on the force of the impact or the
type of accident, however, the system may
not operate.
■Operation signals
A buzzer sounds and the emergency flash-
ers flash to indicate that the doors have
been locked/unlocked. (Locked: once;
Unlocked: twice)
A buzzer sounds to indicate that the win-
dows and moon roof are operating.
■Security feature
If a door is not opened within approximately
60 seconds after the vehicle is unlocked, the security feature automatically locks the
vehicle again.
■Welcome light illumination control
The front position, tail and license plate
lights automatically turn on at night when
the doors are unlocked using the entry
function or wireless remote control if the
light switch is in the “AUTO” position.
■When the doors cannot be locked by the
lock sensor on the upper part of the
door handle
If the door will not lock even when the top-
side sensor area is touched, try touching
both the topside and underside sensor
areas at the same time.
■Door lock buzzer
If an attempt to lock the doors is made when
a door is not fully closed, a buzzer sounds
continuously for 5 seconds. Fully close the
door to stop the buzzer, and lock the vehi-
cle once more.
■Setting the alarm
Locking the doors will set the alarm system.
(  P.62)
■Using the mechanical key
The doors can also be locked and unlocked
with the mechanical key. ( P.359)
■Conditions affecting the operation of
the smart access system with push-but-
ton start or wireless remote control
 P.100
■If the smart access system with
push-button start or the wireless remote
control does not operate properly
Use the mechanical key to lock and unlock
the doors. ( P.359)
Replace the key battery with a new one if it
is depleted. ( P.316)
Multi-information
display/BeepUnlocking function
Exterior: Beeps 3 times
Interior: Pings once
Holding the driver’s
door handle unlocks
only the driver’s
door.
Holding the front
passenger’s door
handle unlocks all
the doors.
Exterior: Beeps twice
Interior: Pings once
Holding either front
door handle unlocks
all the doors.

1013-2. Opening, closing and locking the doors and trunk
3
Before driving
gas station, radio station, large display,
airport or other faci lity that generates
strong radio waves or electrical noise
●When carrying a portable radio, cellular
phone, cordless phone or other wireless
communication device
●When the electronic key is in contact
with, or is covered by the following metal-
lic objects
• Cards to which aluminum foil is attached
• Cigarette boxes that have aluminum foil
inside
• Metallic wallets or bags
•Coins
• Hand warmers made of metal
• Media such as CDs and DVDs
●When other wireless ke ys (that emit radio
waves) are being used nearby
●When carrying the electronic key
together with the following devices that
emit radio waves
• Another vehicle’s electronic key or a wireless key that emits radio waves
• Personal computers or personal digital assistants (PDAs)
• Digital audio players
• Portable game systems
●If window tint with a metallic content or
metallic objects are attached to the rear
window
■Note for the entry function
●Even when the electronic key is within the
effective range (detection areas), the sys-
tem may not operate properly in the fol-
lowing cases:
• The electronic key is too close to the win- dow or outside door handle, near the
ground, or in a high place when the doors
are locked or unlocked.
• The electronic key is near the ground or
in a high place, or too close to the rear
bumper center when the trunk is opened.
• The electronic key is on the instrument panel, rear package tray or floor, or in the
door pockets or glove box when the
engine is started or engine switch modes
are changed.
●Do not leave the electronic key on top of
the instrument panel or near the door
pockets when exiting the vehicle.
Depending on the radio wave reception conditions, it may be detected by the
antenna outside the cabin and the doors
will become lockable from the outside,
possibly trapping the electronic key
inside the vehicle.
●As long as the electronic key is within the
effective range, the doors may be locked
or unlocked by anyone. However, only
the doors detecting the electronic key
can be used to unlock the vehicle.
●Even if the electronic
key is not inside the
vehicle, it may be po ssible to start the
engine if the electronic key is near the
window.
●The doors may unlock or lock if a large
amount of water splashes on the door
handle, such as in the rain or in a car
wash, when the electronic key is within
the effective range. (The doors will auto-
matically be locked after approximately
30 seconds if the doors are not opened
and closed.)
●If the wireless remote control is used to
lock the doors when the electronic key is
near the vehicle, there is a possibility that
the door may not be unlocked by the
entry function. (Use the wireless remote
control to unlock the doors.)
●Touching the door lock or unlock sensor
while wearing gloves may prevent lock or
unlock operation.
●When the lock operation is performed
using the lock sensor, recognition signals
will be shown up to two consecutive
times. After this, no recognition signals
will be given.
●If the door handle becomes wet while the
electronic key is within the effective
range, the door may lock and unlock
repeatedly. In this case, follow the follow-
ing correction procedures to wash the
vehicle:
• Place the electronic key in a location 6 ft. (2 m) or more away from the vehicle.
(Take care to ensure that the key is not
stolen.)
• Set the electronic key to battery-saving mode to disable the smart access system
with push-button start. ( P.100)
●If the electronic key is inside the vehicle
and a door handle becomes wet during a

1344-2. Driving procedures
4-2.Driving procedures
1Check that the parking brake is set.
2 Check that the shift lever is in P.
3 Firmly depress the brake pedal.
and a message will be displayed on
the multi-information display.
If it is not displayed, the engine cannot be
started.
4 Press the engine switch shortly and
firmly.
When operating the engine switch, one
short, firm press is enough. It is not neces-
sary to press and hold the switch.
The engine will crank until it starts or for up
to 30 seconds, whichever is less.
Continue depressing the brake pedal until
the engine is completely started.
The engine can be started from any engine
switch mode.
■If the engine does not start
●Check that the shift leve r is securely set in
P. The engine may not start if the shift
lever is displaced out of P.
●The engine immobilizer system may not
have been deactivated. ( P.60)
Contact your Lexus dealer.
■Electronic key battery depletion
 P.88
■Conditions affecting operation
 P.100
■Notes for the entry function
 P.101
■Steering lock function
●After turning the engine switch off and
opening and closing the doors, the steer-
ing wheel will be lock ed due to the steer-
ing lock function. Operating the engine
switch again automatically cancels the
steering lock.
●When the steering lock cannot be
released, “Push Engine Switch while
Turning Steering Whee l in Either Direc-
tion” will be displayed on the multi-infor-
mation display.
Check that the shift lever is in P. Press the
engine switch while turning the steering
wheel left and right.
●To prevent the steering lock motor from
overheating, operation of the motor may
be suspended if the engine is turned on
and off repeatedly in a short period of
time. In this case, refrain from operating
the engine switch. After about 10 sec-
onds, the steering lock motor will resume
functioning.
■When “Access System with Elec. Key
Malfunction See Owner's Manual” is
displayed on the multi-information dis-
play
The system may be ma lfunctioning. Have
the vehicle inspected by your Lexus dealer
immediately.
Engine (ignition) switch
Performing the following opera-
tions when carryin g the electronic
key on your person starts the
engine or changes engine switch
modes.
Starting the engine

1354-2. Driving procedures
4
Driving
■If the electronic key battery is depleted
 P.316
■Operation of the engine switch
●If the switch is not pressed shortly and
firmly, the engine switch mode may not
change or the engine may not start.
●If attempting to restart the engine imme-
diately after turning the engine switch off,
the engine may not start in some cases.
After turning the engine switch off, please
wait a few seconds before restarting the
engine.
■If the smart access system with
push-button start has been deactivated
by a customized setting
 P.359
1 Stop the vehicle.
2 Set the parking brake ( P.143),
and shift the shift lever to P.
3 Press the engine switch.
4 Release the brake pedal and check
that the display on the meters is off.
■Automatic engine shut off feature
●The vehicle is equipped with a feature
that automatically shuts off the engine
when the shift lever is in P with the engine
running for an extended period.
●The engine will automatically shut off
after approximately 1 hour if it has been
left running while the shift lever is in P.
●The timer for the automatic engine shut
off feature will reset if the brake pedal is
depressed or if the shift lever is in a posi-
tion other than P.
●After the vehicle is parked, if the door is
locked with the door lock switch ( P.94)
from the inside or the mechanical key
from the outside, the automatic engine
shut off feature will be disabled. The timer
for the automatic engine shut off feature
will be re-enabled if the driver’s door is
opened.
WARNING
■When starting the engine
Always start the engine while sitting in
the driver’s seat. Do not depress the
accelerator pedal while starting the
engine under any circumstances.
Doing so may cause an accident result-
ing in death or serious injury.
■Caution while driving
If engine failure occurs while the vehicle
is moving, do not lock or open the doors
until the vehicle reaches a safe and com-
plete stop. Activation of the steering lock
in this circumstance may lead to an acci-
dent, resulting in death or serious injury.
NOTICE
■When starting the engine
●Do not race a cold engine.
●If the engine becomes difficult to start
or stalls frequently, have your vehicle
checked by your Lexus dealer immedi-
ately.
■Symptoms indicating a malfunction
with the engine switch
If the engine switch seems to be operat-
ing somewhat differently than usual, such
as the switch sticking slightly, there may
be a malfunction. Contact your Lexus
dealer immediately.
Stopping the engine

3487-2. Steps to take in an emergency
Check the engine oil and change it if neces-
sary. After changing the engine oil, make
sure to reset the message. ( P.298)
■If “Oil Maintenance Required” is dis-
played
Indicates that the engine oil should be
changed.
Check and change the en gine oil, and oil fil-
ter by your Lexus deal er. After changing the
engine oil, make sure to reset the message.
(  P.298)
■If a message that in dicates the need for
visiting your Lexus dealer is displayed
The system or part shown on the
multi-information display is malfunctioning.
Have the vehicle inspected by your Lexus
dealer immediately.
■If a message that in dicates the need for
referring to Owner’s Manual is dis-
played
●If any of the following messages are
shown on the multi-information display,
follow the instructions.
• “Engine Coolant Temp High” ( P.365)
• “High Transmission Fluid Temp” ( P.138)
●If any of the following messages are
shown on the multi-information display, it
may indicate a malfunction. Have the
vehicle inspected by your Lexus dealer
immediately.
• “Access System with Elec. Key Malfunc-
tion”
●If any of the following messages are
shown on the multi-information display, it
may indicate a malfunction. Immediately
stop the vehicle and contact your Lexus
dealer.
• “Braking Power Low”
• “Charging System Malfunction”
• “Oil Pressure Low”
NOTICE
■If “High Power Consumption Power
to Climate Temporarily Limited” is
displayed frequently
There is a possible malfunction relating
to the charging system or the battery
may be deteriorating. Have the vehicle
inspected by your Lexus dealer.

3617-2. Steps to take in an emergency
7
When trouble arises
be started, contact your Lexus dealer.
■Stopping the engine
Shift the shift lever to P and press the engine
switch as you normally do when stopping
the engine.
■Replacing the key battery
As the above procedure is a temporary
measure, it is recomme nded that the elec-
tronic key battery be replaced immediately
when the battery is depleted. ( P.316)
■Changing engine switch modes
Release the brake pedal and press the
engine switch in step 3 above. The engine
does not start and modes will be changed
each time the switch is pressed. ( P.136)
If the vehicle battery is dis-
charged
The following procedures may be
used to start the engine if the vehi-
cle’s battery is discharged.
You can also call your Lexus dealer
or a qualified repair shop.

423Alphabetical Index
Distance until next engine oil change .....75
Do-it-yourself maintenance .................... 287
Door courtesy lights ................................... 263Wattage........................................................... 381
Door lock Doors.................................................................. 92
Smart access system with push-button start ................................................................... 99
Wireless remote control........................... 90
Doors Automatic door lock ing and unlocking
system ............................................................. 95
Door glasses ................................................... 118
Door lock.......................................................... 92
Open door warning buzzer .......... 93, 94
Outside rear view mirrors ....................... 116
Rear door child-protectors ..................... 94
Drive distance ...................................................79
Drive info 1/Drive info 2/Drive info 3.....79
Driver’s seat position memory Driving position memory........................ 108
Memory recall function ........................... 109
Power easy access system .................... 108
Drive-Start Control (DSC) Sudden start restraint control................ 129
Driving Break-in tips ...................................................125
Correct driving posture .............................23
Driving mode select switch .................. 236
Procedures ..................................................... 124
Winter drive tips......................................... 243
Driving information display ........................ 78
Driving position memory........................... 108 Memory recall function ........................... 109
Power easy access system .................... 108
Driving range ....................................................79
Driving support system information display ...............................................................................81
DSC (Drive-Start Control) Sudden start restraint control................ 129 Dynamic radar cruise control with
full-speed range ..........................................192Warning message .................................... 200
E
Eco Driving Indicator.................................... 80
Eco Driving Indicator Light ........................ 80
EDR (Event data recorder) ............................7
Elapsed time ......................................................79
Electric Power Steering (EPS) .............. 238 Warning light .............................................. 340
Electronic key .................................................. 88 Battery-saving function............................100
If the electronic key does not operate properly ...................................................... 359
Replacing the battery ................................ 316
Emergency flashers .................................... 328
Emergency, in case of If a warning buzzer sounds................... 337
If a warning light turns on....................... 337
If a warning message is displayed .....346
If the battery is discharged ..................... 361
If the electronic key does not operate properly ...................................................... 359
If the engine will not start........................357
If the fuel filler do or cannot be opened
......................................................................... 359
If the vehicle is trapped in rising water ..........................................................................329
If you have a flat tire ..................................349
If you lose your keys ................................ 358
If you think something is wrong..........335
If your vehicle becomes stuck ............ 368
If your vehicle has to be stopped in an emergency .................................................328
If your vehicle needs to be towed ...... 331
If your vehicle overheats ....................... 365
Engine ACCESSORY mode............................... 136
Compartment..............................................295
Engine switch .................................................134
Fuel pump shut off system.....................336