2021 LEXUS ES350 key battery

3416-3. Do-it-yourself maintenance
6
Maintenance and care
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access syst em with push-but-
ton start and wireless remote control will
not function properly.
●The operational rang e will be reduced.
Prepare the following before replacing
the battery:
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
the local laws.
1 Take out the mechanical key. 2
Remove the cover.
To prevent damage to the key, wrap the tip
of the screwdri ver with tape.
3Remove the depleted battery.
Insert a new battery with the “+” terminal
facing up.
Electronic key battery
Replace the battery with a new one
if it is depleted.
Items to prepare
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
chemical burns in as little as 2 hours
and may result in death or serious
injury.
●Keep away new and removed batter-
ies from children.

3426-3. Do-it-yourself maintenance
1Turn the engine switch off.
2 Open the Fuse box cover.
Engine compartment: type A fuse
box
Push the tab in and lift the lid off.
Engine compartment: type B fuse
box
Push the tab in and lift the lid off.
Driver’s side instrument panel
Push the tab in and remove the lid.
WARNING
●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
■When replacing the battery
Use a screwdriver of appropriate size.
Applying excessive force may deform or
damage the cover.
■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.
Checking and replacing
fuses
If any of the electrical components
do not operate, a fuse may have
blown. If this happens, check and
replace the fuses as necessary.
Checking and replacing fuses

351
7
7
When trouble arises
When trouble arises
7-1. Essential informationEmergency flashers.................. 352
If your vehicle has to be stopped in an emergency ..................... 352
If the vehicle is trapped in rising water............................................ 353
7-2. Steps to take in an emergency If your vehicle needs to be towed........................................................ 355
If you think something is wrong ........................................................ 359
Fuel pump shut off system ..... 360
If a warning light turns on or a warning buzzer sounds ........ 361
If a warning message is displayed ......................................................... 371
If you have a flat tire.................. 375
If the engine wi ll not start .......384
If you lose your keys ................. 386
If the fuel filler door cannot be opened........................................ 386
If the electronic key does not operate properly .................... 387
If the battery is discharged .... 389
If your vehicle overheats ........ 393
If the vehicle becomes stuck 395

3847-2. Steps to take in an emergency
One of the following may be the cause
of the problem:
The electronic key may not be func-
tioning properly. ( P.388)
 There may not be sufficient fuel in
the vehicle’s tank.
Refuel the vehicle. ( P.169)
 The engine may be flooded.
Try to restart the engine again fol-
lowing correct starting procedures.
( P.144)
 There may be a malfunction in the
engine immobilizer system. ( P.61)
 There may be a malfunction in the
steering lock system.
One of the following may be the cause
of the problem:
 The battery may be discharged.
( P.389)
NOTICE
■When replacing the tires
When removing or fitting the wheels,
tires or the tire pressure warning valve
and transmitter, contact your Lexus
dealer as the tire pr essure warning valve
and transmitter may be damaged if not
handled correctly.
If the engine will not start
If the engine will not start even
though correct starting procedures
are being followed ( P.144), 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.

3857-2. Steps to take in an emergency
7
When trouble arises
The battery terminal connections
may be loose or corroded.
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.
One of the following may be the cause
of the problem:
 One or both of the battery terminals
may be disconnected.
 The battery may be discharged.
( P.389)
 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
Press the parking brake switch to
check that the parking brake is set.
(P.154)
Parking brake indicator will come on.
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
headlights do not turn on, or the
horn does not sound.
Starting the engine in an emer-
gency

3877-2. Steps to take in an emergency
7
When trouble arises
■When the electronic key does not work
properly
●Make sure that the smart access system
with push-button start has not been deac-
tivated using the Remote Touch or at
your Lexus dealer. If it is off, turn the func-
tion on.
●Check if battery-saving mode is set. If it is
set, cancel the function. ( P.107)
Use the mechanical key ( P.94) in
order to perform the following opera-
tions:
■Unlocking the door
1 Pull the driver’s door handle and
insert the mechanical key.
2 Unlock the door.
3 Remove the key, return the handle,
and then pull the handle again.
■Locking the door
1 With the door open, push down the
inside lock button.
2 Close the door.
■Opening the trunk
Turn the mechanical key clockwise to
If the electronic key does not
operate properly
If communication between the
electronic key and vehicle is inter-
rupted ( P.108) 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-related problems
Take your vehicle with all the electronic
keys provided with your vehicle to your
Lexus dealer as soon as possible.
Locking and unlocking the
doors, opening the trunk and
using the key linked functions

3897-2. Steps to take in an emergency
7
When trouble arises
4Press the engine switch shortly and
firmly.
In the event that the engine still cannot
be started, 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. ( P.341)
■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.147)
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 using the following procedure.
1 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.64)
2 Open the hood. ( P.316)
3 Connect a positive jumper cable clamp to on your vehicle and connect the
clamp on the other end of the positive cable to on the second vehicle.
Then, connect a negative cable clamp to on the second vehicle and con-
nect the clamp at the other end of the negative cable to .
If the battery is discharged
The following procedures may be
used to start the engine if the bat-
tery is discharged.
You can also call your Lexus dealer
or a qualified repair shop.
Restarting the engine
A
B
C
D

3917-2. Steps to take in an emergency
7
When trouble arises
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.
6 Maintain 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 vehicle
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 stopped.
●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 the battery is removed or dis-
charged
●Information stored in the ECU is cleared.
When the battery is depleted, have the
vehicle inspected at your Lexus dealer.
●Some systems may require initialization.
(  P.430)
■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 recharging or replacing the bat-
tery
●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.
■When replacing the battery
●Use a battery that conforms to European
regulations.
●Use a battery that the case size is same as
the previous one (LN3), 20 hour rate
capacity (20HR) is equivalent (70Ah) or
greater, and performance rating (CCA)
is equivalent (592A) or greater.
• If the sizes differ, the battery cannot be properly secured.
• Battery performance may decrease and
the engine may not be able to start.