2021 LEXUS ES300h key battery

3266-3. Do-it-yourself maintenance
The 12-volt battery is located on the
right-hand side of the trunk.
■Before recharging
When recharging, the 12-volt battery pro-
duces hydrogen gas which is flammable
and explosive. Therefore, observe the fol-
lowing precautions before recharging:
●If recharging with the 12-volt battery
installed on the vehicle, be sure to dis-
connect the ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting the charger cables to the 12-volt
battery.
■After recharging/reconnecting the 12-
volt battery
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the 12-volt battery. If this hap-
pens, use the wireless remote control or
the mechanical key to lock/unlock the
doors.
●Start the hybrid system with the power
switch in ACCESSORY mode. The
hybrid system may not start with the
power switch turned off. However, the
hybrid system will operate normally from
the second attempt.
●The power switch mode is recorded by
the vehicle. If the 12-volt battery is recon-
nected, the vehicle will return the power
NOTICE
■Do not use any fluid other than
washer fluid
Do not use soapy water or engine anti-
freeze instead of washer fluid.
Doing so may cause streaking on the
vehicle’s painted surfaces, as well as
damaging the pump leading to problems
of the washer fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as neces-
sary.
Refer to the freezing temperatures listed
on the label of the washer fluid bottle.
12-volt battery
Location

3476-3. Do-it-yourself maintenance
6
Maintenance and care
■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.
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.
1Take out the mechanical key.
NOTICE
■To prevent damage to the vehicle
●Do not allow water or foreign matter
to enter the air intake vent when the
cover is removed.
●Carefully handle the removed filter so
that it will not be damage.
If the filter is damaged, have it
replaced with a new filter by your
Lexus dealer.
●Make sure to reinst all the filter and
cover to their original positions after
cleaning.
●Do not install anything to the air intake
vent other than the exclusive filter for
this vehicle or use the vehicle without
the filter installed.
■If “Maintenance required for Trac-
tion battery cooling parts See
owner’s manual” is displayed on the
multi-information display
If the vehicle is continuously driven with
the warning message (indicating that
charging/discharging of the hybrid bat-
tery (traction battery) may become lim-
ited) displayed, the hybrid battery
(traction battery) may malfunction.
Electronic key battery
Replace the battery with a new one
if it is depleted.
Items to prepare
Replacing the battery

3486-3. Do-it-yourself maintenance
2Remove 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.
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.
●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.

357
7
7
When trouble arises
When trouble arises
7-1. Essential informationEmergency flashers.................. 358
If your vehicle has to be stopped in an emergency ..................... 358
If the vehicle is trapped in rising water............................................ 359
7-2. Steps to take in an emergency If your vehicle needs to be towed......................................................... 361
If you think something is wrong ........................................................ 364
If a warning light turns on or a warning buzzer sounds ....... 365
If a warning message is displayed ........................................................ 375
If you have a flat tire.................. 379
If the hybrid system will not start ........................................................ 386
If you lose your keys ................. 388
If the fuel filler door cannot be opened........................................ 388
If the electronic key does not operate properly .................... 389
If the 12-volt battery is discharged ......................................................... 391
If your vehicle overheats ........ 396
If the vehicle becomes stuck 399

3787-2. Steps to take in an emergency
schedule* should be performed soon.
Comes on approximately 4500 miles
(7200 km) after the message has been
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. ( P.312)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed
Indicates that all maintenance is required to
correspond to the driven distance on the
maintenance schedule
*.
Comes on approximately 5000 miles
(8000 km) after the message has been
reset. (The indicator will not work properly
unless the message ha s been reset.) Per-
form the necessary maintenance. Please
reset the message after the maintenance is
performed. ( P.312)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil should be
scheduled to be changed.
Check the engine oil and change it if neces-
sary. After changing the engine oil, make
sure to reset the message. ( P.312)
■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 de aler. After changing
the engine oil, make sure to reset the mes-
sage. ( P.323)
■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 indicates 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.396)
●If any of the following messages are
shown on the multi-info rmation display, it
may indicate a malfunction. Have the
vehicle inspected by your Lexus dealer
immediately.
• “Access System with Elec. Key Malfunc-
tion”
• “Hybrid system malfunction”
•“Check Engine”
• “Hybrid battery system malfunction”
• “Accelerator system malfunction”
●If any of the following messages are
shown on the multi-info rmation display, it
may indicate a malfun ction. Immediately
stop the vehicle and contact your Lexus
dealer.
• “Braking Power Low”
• “Charging System Malfunction”
• “Oil Pressure Low”
●If any of the following messages are
shown on the multi-information display,
the vehicle may have run out of fuel. Stop
the vehicle in a safe place and, if the fuel
level is low, refuel the vehicle. ( P.64)
• “Hybrid system stopped”
• “Engine stopped”
●If “Low Auxiliary Battery” is shown
• When the display goes off after several
seconds
*:
Maintain the hybrid system operation for
more than 15 minutes and charge the 12-
volt battery.
• When the display does not go off:
Start up the hybrid system using the proce-
dures for “If the 12-volt battery is dis-
charged” ( P.391).
*: Displays for about 6 seconds
●If “Maintenance required for Traction
battery cooling parts” is shown, the filter
may be clogged, the air intake vent may

3867-2. 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.390)
 There may not be sufficient fuel in
the vehicle’s tank.
Refuel the vehicle. ( P.172)
 There may be a malfunction in the
immobilizer system. ( P.69)
 There may be a malfunction in the
steering lock system.
 The hybrid system may be malfunc-
tioning due to an electrical problem
such as electronic key battery
depletion or a blown fuse. However,
depending on the type of malfunc-
tion, an interim measure is available
to start the hybrid system.
 For vehicles sold in except Canada:
There is a possibility that the tem-
perature of the hybrid battery (trac-
tion battery) is extremely low
(approximately below -22°F [-
30°C]). ( P.65, 145)
WARNING
■Speed limit when using the compact
spare tire
Do not drive at speeds in excess of 50
mph (80 km/h) when a compact spare
tire is installed on the vehicle.
The compact spare tire is not designed
for driving at high speeds. Failure to
observe this precaution may lead to an
accident causing deat h or serious injury.
■After using the tools and jack
Before driving, make sure all the tools
and jack are securely in place in their
storage location to reduce the possibility
of personal injury during a collision or
sudden braking.
NOTICE
■Be careful when driving over bumps
with the compact spare tire installed
on the vehicle
The vehicle becomes lower when driving
with the compact spare tire compared to
when driving with standard tires. Be
careful when driving over uneven road
surfaces.
■Driving with tire chains and the com-
pact spare tire
Do not fit tire chains to the compact
spare tire.
Tire chains may damage the vehicle
body and adversely affect driving perfor-
mance.
■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 hybrid system will not
start
Reasons for the hybrid system not
starting vary depending on the situ-
ation. Check the following and per-
form the appropriate procedure:
The hybrid system will not start
even though the correct starting
procedure is being followed.
(  P.145)

3897-2. 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.113)
Use the mechanical key ( P.100) 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.114) 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 hybrid system can be started by
following 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

3917-2. Steps to take in an emergency
7
When trouble arises
In the event that the hybrid system still
cannot be started, contact your Lexus
dealer.
■Stopping the hybrid system
Set the parking brake, shift the shift lever to
P and press the power switch as you nor-
mally do when stopping the hybrid system.
■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.347)
■Changing power switch modes
Release the brake pedal and press the
power switch in step 3 above.
The hybrid system does not start and modes
will be changed each time the switch is
pressed. ( P.148)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.72)
2 Open the hood ( P.319) and
open the fuse box cover.
If the 12-volt battery is dis-
charged
The following procedures may be
used to start the hybrid system if the
12-volt battery is discharged.
You can also call your Lexus dealer
or a qualified repair shop.
Restarting the hybrid system