2020 LEXUS NX300 change key battery

701-4. Theft deterrent system
LEXUS NX300 Owners Manual_USA_M78389_en
■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 and hood, and lock all
the doors. The system will be set auto-
matically after 30 seconds.
The indicator light changes from being on
to flashing when the system is set.
■Canceling or stopping
Do one of the following to deactivate
or stop the alarms:
 Unlock the doors.
 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 hood, or unlocks the vehicle using an
inside lock button.
●The battery is recharged or replaced
when the vehicle is locked. ( P.402)
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 is unlocked or
opened in any way other than
using the entry function, wireless
remote control or mechanical
key. (The doors will lock again
automatically.)
 The hood is opened.
Setting/canceling/stopping the
alarm system

1023-2. Opening, closing and locking the doors
LEXUS NX300 Owners Manual_USA_M78389_en
■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.70)
■Conditions affecting the operation of
the smart access system with push-but-
ton start or wireless remote control
 P.118
■If the smart access system with push-
button start or the wireless remote con-
trol does not operate properly
●Use the mechanical key to lock and
unlock the doors. ( P.398)
●Replace the key battery with a new one if
it is depleted.
■Customization
Settings (e.g. unlocking function using a
key) can be changed. (Customizable fea-
tures: P.427)
■Using the door lock switches
1
Locks all the doors
WARNING
■To prevent an accident
Observe the following precautions while
driving the vehicle.
Failure to do so may result in a door
opening and an occupant falling out,
resulting in death or serious injury.
●Ensure that all doors are properly
closed and locked.
●Do not pull the inside handle of the
doors while driving.
Be especially careful for the front
doors, as the doors may be opened
even if the inside lock buttons are in
locked position.
●Set the rear door child-protector locks
when children are seated in the rear
seats.
■When opening or closing a door
Check the surroundings of the vehicle
such as whether the vehicle is on an
incline, whether there is enough space
for a door to open and whether a strong
wind is blowing. When opening or clos-
ing the door, hold the door handle tightly
to prepare for any unpredictable move-
ment.
■When using the wireless remote con-
trol and operating the power windows
or moon roof (if equipped)
Operate the power window or moon
roof after checking to make sure that
there is no possibility of any passenger
having any of their body parts caught in
the window or moon roof. Also do not let
a child operate window by the mechani-
cal key. It is possible for children and
other passengers to get caught in the
power window or moon roof.
Unlocking and locking the doors
from the inside

1183-2. Opening, closing and locking the doors
LEXUS NX300 Owners Manual_USA_M78389_en
tronic key from re
ceiving radio waves.
Press twice while pressing and
holding .
Confirm that the elec tronic key indicator
flashes 4 times. While the battery-saving
mode is set, the smar t access system with
push-button start cannot be used. To cancel
the function, press any of the electronic key
buttons.
■Conditions affe cting operation
The smart access system with push-button
start, wireless remote control and immobi-
lizer system use weak radio waves. In the
following situations, the communication
between the electronic key and the vehicle
may be affected, preventing the smart
access system with push -button start, wire-
less remote control and immobilizer system
from operating properly. (Ways of coping:
 P.397)
●When the electronic key battery is
depleted
●Near a TV tower, electric power plant,
gas station, radio stat ion, large display,
airport or other faci lity that generates
strong radio waves or electrical noise
●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
• Portable radio, cellular phone, cordless
phone or other wireless communication
devices
• 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
●When the electronic key is placed near a
battery charger or electronic devices
■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 back door is
opened.
• The electronic key is on the instrument panel, luggage room, 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 door
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.
●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 if a large amount

1193-2. Opening, closing and locking the doors
LEXUS NX300 Owners Manual_USA_M78389_en
3
Before driving
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 door will automatically be
locked after approximately 60 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 sensor while
wearing gloves may delay or prevent lock
operation. Remove the gloves and touch
the lock sensor again.
●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 that ca se, 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.117)
●If the electronic key is inside the vehicle
and a door handle becomes wet during a
car wash, a message may be shown on
the multi-information display and a
buzzer will sound outside the vehicle. To
turn off the alarm, lock all the doors.
●The lock sensor may not work properly if
it comes into contact with ice, snow, mud,
etc. Clean the lock sensor and attempt to
operate it again.
●A sudden approach to the effective
range or door handle may prevent the
doors from being unlocked. In this case,
return the door handle to the original
position and check that the doors unlock
before pulling the door handle again.
●If there is another electronic key in the detection area, it may
take slightly longer
to unlock the doors after the door handle
is gripped.
■When the vehicle is not driven for
extended periods
●To prevent theft of the vehicle, do not
leave the electronic key within 6 ft. (2 m)
of the vehicle.
●The smart access system with push-but-
ton start can be deactivated in advance.
■To operate the system properly
Make sure to carry the electronic key when
operating the system. Do not get the elec-
tronic key too close to the vehicle when
operating the system from the outside of the
vehicle.
Depending on the position and holding
condition of the electronic key, the key may
not be detected correctly and the system
may not operate properly. (The alarm may
go off accidentally, or the door lock preven-
tion may not operate.)
■If the smart access system with push but-
ton start does not operate properly
●Locking and unlockin g the doors: Use
the mechanical key. ( P.398)
●Starting the engine: P.398
■Customization
Settings (e.g. smart access system with
push-button start) can be changed. (Cus-
tomizable features: P.427)
If the smart access system with push-button
start has been deactivated by a customized
setting, refer to the explanations for the fol-
lowing operations.
●Locking and unlo cking the doors:
Use the wireless remote control or
mechanical key. ( P.100, 398)
●Starting the engine and changing engine
switch modes:  P.398
●Stopping the engine: P.166

1654-2. Driving procedures
LEXUS NX300 Owners Manual_USA_M78389_en
4
Driving
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 necessary 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
●The engine immobilizer system may not
have been deactivated. ( P.68) Contact your Lexus dealer.
●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. “To Start Vehi-
cle, Put Shift Lever into P” will be dis-
played on the multi-information display.
●The smart access system with push-but-
ton start may not be operating properly.
(  P.398)
■Electronic key battery depletion
 P.96
■Conditions affecting operation
 P.118
■Note for the entry function
 P.118
■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, “Steering Wheel Lock Press
Engine Switch while Turning Wheel” will
be displayed on the multi-information dis-
play.
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 running the
engine. After about 10 seconds, the
steering lock motor will resume function-
ing.
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

1664-2. Driving procedures
LEXUS NX300 Owners Manual_USA_M78389_en
■If “Smart Access System Malfunction
See Owner’s Manual” is displayed on
the multi-information display
The system may be malfunctioning. Have
the vehicle inspected by your Lexus dealer
immediately.
■Electronic key battery
 P.356
■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.427
1Stop the vehicle completely.
2
Set the parking brake ( P.173),
and shift the shift lever to P
( P.168).
3
Press the engine switch.
4
Release the brake pedal and check
that the display on the instrument
cluster is off.
Modes can be changed by pressing
the engine switch with brake pedal
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. The steering lock function will
activate and this may lead to an accident,
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
WARNING
■Stopping the engine in an emergency
If you want to stop th e engine in an emer-
gency while driving the vehicle, press
and hold the engine switch for more than
2 seconds, or press it briefly 3 times or
more in succession. ( P.366)
However, do not touch the engine switch
while driving except in an emergency.
Turning the engine off while driving will
not cause loss of steering or braking con-
trol, but the power assist to these systems
will be lost. This will make it more difficult
to steer and brake, so you should pull
over and stop the vehicle as soon as it is
safe to do so.
Changing engine switch modes

3997-2. Steps to take in an emergency
LEXUS NX300 Owners Manual_USA_M78389_en
7
When trouble arises
ACCESSORY mode.
3Firmly depress the brake pedal and
check that message shown on the
multi-information display.
4 Press the engine switch.
In the event that the engine still cannot be
operated, contact your Lexus dealer.
■Stopping the engine
Set the parking brake, shift the shift lever to
P and press the engine switch as you nor-
mally do when stopping the engine.
■Electronic 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.
■Alarm
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.
■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.166)