2021 LEXUS RX350 key battery

3796-3. Do-it-yourself maintenance
6
Maintenance and care
■Replacing the rear wiper insert
Have the rear wiper inse rt replaced by your
Lexus dealer.
■Handling of the windshield wiper blades
and inserts
Improper handling of the windshield wiper
blades and inserts may cause them to be
damaged. If it is difficult to follow the wiper
blade and insert replacement procedure
precisely, contact your Lexus dealer.
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-but-
ton start and wireless remote control will
not function properly.
●The operationa l range will be reduced.
Flathead screwdriver
 Lithium battery CR2032
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus
dealer, local electrical appliance shops or
camera stores.
●Replace only with the same or equivalent
type recommended by the manufacturer.
●Dispose of used batteries according to
the local laws.
1Take out the mechanical key.
2 Remove the cover.
To prevent damage to the key, cover the tip
Electronic key battery
Replace the battery with a new one
if it is depleted.
You will need the following items:
Replacing the battery

3806-3. Do-it-yourself maintenance
of the flathead screwdriver with a tape.
3Remove the depleted battery.
When removing the cover, the electronic
key module may stick to the cover and the
battery may not be visible. In this case,
remove the electronic key module in order
to remove the battery.
Insert a new battery with the “+” terminal
facing up.
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 chemi-
cal 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
Lexus dealer.
●If you accidentally swallow a battery or
put a battery into a part of your body,
get emergency medical attention
immediately.
■To prevent battery explosion or leak-
age of flammable liquid or gas
●Replace the battery with a new battery
of the same type. If a wrong 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 com-
ponent inside the remote control.
●Do not bend either of the battery ter-
minals.

393
7
7
When trouble arises
When trouble arises
.7-1. Essential informationEmergency flashers.................. 394
If your vehicle has to be stopped in an emergency .......................... 394
If the vehicle is trapped in rising water............................................ 395
7-2. Steps to take in an emergency If your vehicle needs to be towed........................................................ 397
If you think something is wrong ......................................................... 401
Fuel pump shut off system ..... 402
If a warning light turns on or a warning buzzer sounds ....... 403
If a warning message is displayed ......................................................... 412
If you have a flat tire................... 416
If the engine wi ll not start .......428
If you lose your keys ................. 430
If the fuel filler door cannot be opened........................................ 430
If the electronic key does not operate properly ..................... 431
If the vehicle battery is discharged ........................................................ 433
If your vehicle overheats ........ 437
If the vehicle becomes stuck ........................................................ 439

4297-2. Steps to take in an emergency
7
When trouble arises
The engine starting system may be
malfunctioning due to an electrical
problem such as electronic key battery
depletion or a blown fuse. However, an
interim measure is available to start the
engine. (P.429)
One of the following may be the cause
of the problem:
 One or both of the battery terminals
may be disconnected. ( P.363)
 The battery may be discharged.
( P.433)
 There may be a malfunction in the
steering lock system.
Contact your Lexus dealer if the problem
cannot be repaired, or if repair procedures
are unknown.
When the engine does not start, the
following steps can be used as an
interim measure to start the engine if
the engine switch is functioning nor-
mally.
Do not use this starting procedure
except in cases of emergency.
1 Turn the engine switch to IGNI-
TION ON mode and check that the parking brake is set. (
P.177,
183)
2 Shift the shift lever to P.
3 Turn the engine switch to ACCES-
SORY mode.
4 Press and hold the engine switch
for about 15 seconds while
depressing the brake pedal firmly.
Even if the engine can be started using
the above steps, the system may be
malfunctioning. Have the vehicle
inspected by your Lexus dealer.
The starter motor does not turn
over
The starter motor does not turn
over, the interior lights and head-
lights do not turn on, or the horn
does not sound.
Starting the engine in an emer-
gency

4317-2. Steps to take in an emergency
7
When trouble arises
wrap its tip with tape to protect the cover.
■When the electronic key does not work
properly
●Make sure that the smart access system
with push-button start has not been dis-
abled at your Lexus dealer. If it has been
disabled, re-enable it.
●Check if battery-saving mo de is set. If it is
set, cancel the function. ( P.116)
■Unlocking the door
Use the mechanical key ( P.97) in
order to perform th e following opera-
tions:
If the electronic key does not
operate properly
If communication between the
electronic key and vehicle is inter-
rupted ( P.116) or the electronic
key cannot be used because the
battery is depleted, the smart
access system with push-button
start and wireless remote control
cannot be used. In such cases, the
doors can be opened and the
engine can be started by following
the procedure below.
NOTICE
■In case of a smart access system with
push-button start malfunction or
other key-rela ted problems
Take your vehicle with all the electronic
keys provided with your vehicle to your
Lexus dealer.
Locking and unlocking the doors

4337-2. Steps to take in an emergency
7
When trouble arises
When the smart access system with
push-button start is deactivated in custom-
ization setting, the engine switch will turn
to ACCESSORY mode.
3 Firmly depress the brake pedal and
check that is shown on the
multi-information display.
4 Press the engine switch shortly and
firmly.
In the event that the engine still cannot
be started, contact your Lexus dealer.
■Stopping the engine
Shift the shift lever to P, set the parking
brake, 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.379)
■Alarm (For Canada)
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.68)
■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.177)
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.

4347-2. Steps to take in an emergency
If you have a set of jumper (or booster)
cables and a second vehicle with a bat-
tery, you can jump start your vehicle by
following the steps below.
1Confirm 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.69)
2 Open the hood. ( P.357)
3 Connect a positive jumper cable clamp to on your vehicle and connect the
clamp on the other end of the positive cab le to on the second vehicle. Then,
connect a negative cable clamp to on the second vehicle and connect the
clamp at the other end of the negative cable to .
Positive (+) battery terminal (your vehicle)
Positive (+) battery terminal (second vehicle)
Negative (-) battery terminal (second vehicle)
Solid, stationary, unpainted metallic poin t away from the battery and any mov-
ing parts as shown in the illustration
4 Start the engine of the second vehi-
cle. Increase the engine speed
slightly and maintain at that level for
approximately 5 minutes to recharge the battery of your vehi-
cle.
5 Open and close any of the doors of
your vehicle with the engine switch
off.
Restarting the engine
A
B
C
D
A
B
C
D

4357-2. Steps to take in an emergency
7
When trouble arises
6Maintain the engine speed of the
second vehicle and start the engine
of your vehicle by turning the
engine switch to IGNITION ON
mode.
7 Once the vehicle’s engine has
started, remove the jumper cables
in the exact reverse order from
which they were connected.
Once the engine starts, have the vehi-
cle inspected at your Lexus dealer as
soon as possible.
■Starting the engine when the battery is
discharged
The engine cannot be started by push-start-
ing.
■To prevent battery discharge
●Turn off the headlights and the audio sys-
tem while the engine is off.
●Turn off any unnecessary electrical com-
ponents when the vehicle is running at a
low speed for an extended period, such
as in heavy traffic.
■When removing the battery terminals
When the battery terminals are removed,
the information stored in the ECU is
cleared. Before removi ng the battery termi-
nals, contact your Lexus dealer.
■Charging the battery
The electricity stored in the battery will dis-
charge gradually even when the vehicle is
not in use, due to natural discharge and the
draining effects of certain electrical appli-
ances. If the vehicle is left for a long time,
the battery may discharge, and the engine
may be unable to start. (The battery
recharges automatically during driving.)
■When the battery is removed or dis-
charged
●In some cases, it may not be possible to
unlock the doors using the smart access
system with push-button start when the
battery is discharged. Use the wireless remote control or the mechanical key to
lock or unlock the doors.
●The engine may not start on the first
attempt after the battery has recharged
but will start normally after the second
attempt. This is not a malfunction.
●The engine switch mode is memorized by
the vehicle. When the battery is recon-
nected, the system will return to the
mode it was in before the battery was dis-
charged. Before disconnecting the bat-
tery, turn the engine switch off.
If you are unsure wh
at mode the engine
switch was in before the battery dis-
charged, be especially careful when
reconnecting the battery.
●The power back door must be initialized.
(  P.109)
■Replacing the battery
●Use a battery with the same case size as
the previous battery and an equivalent
20 hour rate capacity (20HR) or greater.
• If the sizes differ, the battery cannot be properly secured.
• If the 20 hour rate capacity is low, even if the time period where the vehicle is not
used is a short time, the battery may dis-
charge and the engine may not be able to
start.
●For details, consult your Lexus dealer.
WARNING
■When removing the battery terminals
Always remove the negative (-) terminal
first. If the positive (+) terminal contacts
any metal in the surrounding area when
the positive (+) terminal is removed, a
spark may occur, leading to a fire in addi-
tion to electrical shocks and death or
serious injury.
■Avoiding battery fires or explosions
Observe the following precautions to
prevent accidentally igniting the flamma-
ble gas that may be emitted from the bat-
tery: