2021 Lexus IS350 key battery

3016-3. Do-it-yourself maintenance
6
Maintenance and care
Check the battery as follows.
■Battery exterior
Make sure that the battery terminals
are not corroded and that there are no
loose connections, cracks, or loose
clamps.
Terminals
Hold-down clamp
■Before recharging
When recharging, the battery produces
hydrogen gas which is flammable and
explosive. Therefore, observe the following
before recharging:
●If recharging with the battery installed on
the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting the charger cables to the battery.
■After recharging/reconnecting the bat-
tery
The engine may not start. Follow the proce-
dure below to initialize the system.
1 Shift the shift lever to P.
2 Open and close any of the doors.
3 Restart the engine.
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the battery. If this happens, use
the wireless remote control or the
mechanical key to lo ck/unlock the doors.
●Start the engine with the engine switch in
ACCESSORY mode. The engine may
not start with the engine switch turned off.
However, the engine will operate nor-
mally from the second attempt.
●The engine switch mode is recorded by
the vehicle. If the battery is disconnected
and reconnected, the vehicle will return
the engine switch mode to the status it
was in before the battery was discon-
nected. Make sure to turn off the engine
before disconnecting the battery. Take
extra care when connecting the battery if
the engine switch mode prior to the bat-
tery being disconnected is unknown.
If the system will not start even after multiple
attempts, contact your Lexus dealer.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid level in the accumulator
is high.
If the reservoir need s frequent refilling,
there may be a serious problem.
Battery
A
B
WARNING
■Chemicals in the battery
Batteries contain poisonous and corro-
sive sulfuric acid and may produce
hydrogen gas which is flammable and
explosive. To reduce the risk of death or
serious injury, take the following precau-
tions while working on or near the bat-
tery:
●Do not cause sparks by touching the
battery terminals with tools.
●Do not smoke or light a match near the
battery.
●Avoid contact with eyes, skin and
clothes.

3166-3. Do-it-yourself maintenance
When an air conditioning odor comes out
continuously, replace the air conditioning
filter.
■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.
■When the card key battery needs to be
replaced (if equipped)
The battery for the card key is available only
at Lexus dealers. Your Lexus dealer can
replace the battery for you.
 Flathead screwdriver
 Small 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
local laws.
NOTICE
■When using the air conditioning sys-
tem
Make sure that a filter is always installed.
Using the air conditioning system without
a filter may cause damage to the system.
Electronic key battery
Replace the battery with a new one
if it is depleted.
As the key may be damaged if the
following procedure is not per-
formed properly, it is recom-
mended that key battery
replacement be performed by your
Lexus dealer.
Items to prepare

3176-3. Do-it-yourself maintenance
6
Maintenance and care
1Take out the mechanical key.
2 Remove the cover.
To prevent damage to the key, wrap the tip
of the screwdriver with tape.
3Remove the depleted battery.
Insert a new battery with the “+” terminal
facing up.
Replacing the battery
WARNING
■Battery precautions
Observe the following precautions. Fail-
ure to do so may result in death or seri-
ous 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.

327
7
7
When trouble arises
When trouble arises
.7-1. Essential informationEmergency flashers.................. 328
If your vehicle has to be stopped in an emergency .......................... 328
If the vehicle is trapped in rising water............................................ 329
7-2. Steps to take in an emergency If your vehicle needs to be towed......................................................... 331
If you think something is wrong ........................................................ 335
Fuel pump shut off system ..... 336
If a warning light turns on or a warning buzzer sounds ....... 337
If a warning message is displayed ........................................................ 346
If you have a flat tire.................. 349
If the engine wi ll not start .......357
If you lose your keys ................. 358
If the fuel filler door cannot be opened........................................ 359
If the electronic key does not operate properly .................... 359
If the vehicle battery is discharged ......................................................... 361
If your vehicle overheats ........ 365
If the vehicle becomes stuck ........................................................ 368

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.

3577-2. Steps to take in an emergency
7
When trouble arises
One of the following may be the cause
of the problem:
There may not be sufficient fuel in
the vehicle’s tank.
Refuel the vehicle.
 The engine may be flooded.
Try to restart the engine again fol-
lowing correct starting procedures.
( P.134)
 There may be a malfunction in the
engine immobilizer system.
( P.60)
One of the following may be the cause
of the problem:
 The battery may be discharged.
( P.361)
 The battery terminal connections
may be loose or corroded.
( P.301) 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.357)
One of the following may be the cause
of the problem:
 One or both of the battery terminals
may be disconnected. ( P.301)
 The battery may be discharged.
( P.361)
 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:
1 Push the parking brake switch to
check that the parking brake is set.
(P.143)
Parking brake indicator will come on.
If the engine will not start
If the engine will not start even
though correct starting procedures
are being followed ( P.134), con-
sider each of the following points:
The engine will not start even
though the starter motor oper-
ates normally.
The starter motor turns over
slowly, the interior lights and
headlights are dim, or the horn
does not sound or sounds at a low
volume.
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

3597-2. Steps to take in an emergency
7
When trouble arises
Remove the cover inside the trunk and
pull the lever.
■When the electronic key does not work
properly
●Make sure that the smart access system
with push-button start has not been deac-
tivated in the customization setting. If it is
off, turn the function on.
●Check if battery-saving mo de is set. If it is
set, cancel the function. ( P.100)
■Doors
Use the mechanical key ( P.90) in
order to perform th e following opera-
tions:
If the fuel filler door cannot
be opened
If the fuel filler door cannot be
opened by pressing the center of
the rear edge of the fuel filler door
with the doors unlocked, the follow-
ing procedure can be used to open
the fuel filler door.
Opening the fuel filler door
If the electronic key does not
operate properly
If communication between the
electronic key and vehicle is inter-
rupted ( P.100) 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 and trunk can be opened and
the engine can be started by follow-
ing 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, unlocking the trunk

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.