2020 Lexus ES300h battery

3166-2. Maintenance
The OBD system determines that a
problem exists somewhere in the emis-
sion control system. Your vehicle may
not pass the I/M test and may need to
be repaired. Contact your Lexus
dealer to service the vehicle.
When the 12-volt battery is discon-
nected or discharged
Readiness codes that are set during
ordinary driving are erased.
Also, depending on your driving
habits, the readiness codes may not
be completely set.
 When the fuel tank cap is loose
The malfunction indicator lamp
comes on indicating a temporary
malfunction and your vehicle may
not pass the I/M test. The error code in the OBD system will
not be cleared unless the vehicle is
driven 40 or more times.
Contact your Lexus dealer to prepare
the vehicle for re-testing.
Emission inspection and
maintenance (I/M) pro-
grams
Some states have vehicle emission
inspection programs which include
OBD (On Board Diagnostics)
checks. The OBD system monitors
the operation of the emission con-
trol system.
If the malfunction indicator lamp
comes on
Your vehicle may not pass the
I/M test in the following situa-
tions:
When the malfunction indicator
lamp still remains on after sev-
eral driving trips
If your vehicle does not pass the
I/M test

3176-3. Do-it-yourself maintenance
6
Maintenance and care
6-3.Do-it-yourself maintenance
Do-it-yourself service pre-
cautions
If you perform maintenance by
yourself, be sure to follow the cor-
rect procedure as given in these
sections.
Maintenance
ItemsParts and tools
12-volt battery
condition
( P.326)•Grease
• Conventional wrench
(for terminal clamp
bolts)
Brake fluid
level
( P.325)
• FMVSS No.116 DOT 3
or SAE J1703 brake
fluid
FMVSS No.116 DOT 4
or SAE J1704 brake
fluid
• Rag or paper towel
• Funnel (used only for adding brake fluid)
Engine/power
control unit
coolant level
( P.323)
•“Toyota Super Long Life
Coolant” or a similar
high quality ethylene
glycol-based non-sili-
cate, non-amine, non-
nitrite and non-borate
coolant with long-life
hybrid organic acid
technology
For the U.S.A.:
“Toyota Super Long Life
Coolant” is pre-mixed
with 50% coolant and
50% deionized water.
For Canada:
“Toyota Super Long Life
Coolant” is pre-mixed
with 55% coolant and
45% deionized water.
• Funnel (used only for adding coolant)
Hybrid bat-
tery (traction
battery) air
intake vent
( P.343)
• Vacuum cleaner, etc.
• Phillips screwdriver
Engine oil level
( P.321)
•“Toyota Genuine Motor
Oil” or equivalent
•Rag or paper towel
• Funnel (used only for adding engine oil)
Fuses
( P.348)• Fuse with same amper-
age rating as original
Headlight aim• Phillips-head screw-driver
Light bulbs
( P.351)
•Bulb with same number
and wattage rating as
original
• Flathead screwdriver
ItemsParts and tools

3216-3. Do-it-yourself maintenance
6
Maintenance and care
Fuse boxes (P.348)
Engine oil filler cap ( P.322)
Engine oil level dipstick ( P.321)
Brake fluid reservoir ( P.325)
Radiator ( P.324)
Electric cooling fan
Condenser ( P.324)
Power control unit coolant reservoir ( P.324)
Engine coolant reservoir ( P.323)
Washer fluid tank ( P.325)
■12-volt battery
 P.326
With the engine at operating tempera-
ture and turned off, check the oil level
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
Checking and adding the engine
oil

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 discon-
nect 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

3276-3. Do-it-yourself maintenance
6
Maintenance and care
switch mode to the status it was in before
the 12-volt battery was disconnected.
Make sure to turn off the power switch
before disconnect the 12-volt battery.
Take extra care when connecting the 12-
volt battery if the power switch mode
prior to discharge is unknown.
If the hybrid system will not start even after
multiple attempts at all methods above,
contact your Lexus dealer.
Lift the luggage mat up.
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous
and corrosive sulfuric acid and may pro-
duce hydrogen gas which is flammable
and explosive. To reduce the risk of death
or serious injury, take the following pre-
cautions while working on or near the 12-
volt battery:
●Do not cause sparks by touching the
12-volt battery terminals with tools.
●Do not smoke or light a match near the
12-volt battery.
●Avoid contact with eyes, skin and
clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when
working near the 12-volt battery.
●Keep children away from the 12-volt
battery.
■Where to safely charge the 12-volt
battery
Always charge the 12-volt battery in an
open area. Do not charge the 12-volt bat-
tery in a garage or closed room where
there is insufficient ventilation.
■How to recharge the 12-volt battery
Recharge at a current of 5 A or less and
make sure that the recharging period
does not exceed a total of 12 hours.
■Emergency measures regarding
electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean water for at
least 15 minutes and get immediate
medical attention. If possible, continue
to apply water with a sponge or cloth
while traveling to the nearest medical
facility.
●If electrolyte gets on your skin
Wash the affected area thoroughly. If
you feel pain or burning, get medical
attention immediately.
●If electrolyte gets on your clothes
It can soak through clothing on to your
skin. Immediately take off the clothing
and follow the procedure above if nec-
essary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk.
Get emergency medical attention
immediately.
■When replacing the 12-volt battery
Use a 12-volt battery designed for this
vehicle. Failure to do so may cause gas
(hydrogen) to enter the passenger com-
partment, causing a fire or explosion.
For replacement of the 12-volt battery,
contact your Lexus dealer.
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while
the hybrid system is operating. Also, be
sure all accessories are turned off.
Removing the 12-volt battery
cover

3286-3. Do-it-yourself maintenance
Make sure that the 12-volt battery ter-
minals are not corroded and that there
are no loose connections, cracks, or
loose clamps.Terminals
Hold-down clamp
Check the 12-volt battery condition by
indicator color. Blue: Good condition
Red: Charging is necessary.Have the vehicle inspected by your Lexus
dealer.
Clear: Replacement is necessary.
Have the 12-volt battery checked by your
Lexus dealer.
Exterior
Checking 12-volt battery condi-
tion
A
B
A
B
C

3436-3. Do-it-yourself maintenance
6
Maintenance and care
Remove the dust from the air intake
vent with a vacuum cleaner, etc.
Make sure to only use a vacuum to suck
out dust and clogs. Attempting to blow out
dust and clogs using an airgun, etc. may
push it into the air intake vent. ( P.345)
If dust and clogs cannot be completely
removed with the air intake vent cover
installed, remove the cover and clean the filter.
1
Turn the power switch off.
2 Using a Phillips screwdriver,
remove the clip.
3 Remove the air intake vent cover.
1 Pull the cover as shown in the illus-
tration to disengage the 7 claws,
starting from the claw in the upper
right corner.
2 Pull the cover toward the front of
the vehicle to remove it.
Cleaning the hybrid battery
(traction battery) air intake
vent and filter
To prevent the fuel economy from
being affected, visually inspect the
hybrid battery (traction battery) air
intake vent periodically for dust and
clogs. If it is dusty or clogged or if
“Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is displayed on
the multi-information display, clean
the air intake vent using the follow-
ing procedures:
Cleaning the air intake vent
If dust and clogs cannot be com-
pletely removed

3456-3. Do-it-yourself maintenance
6
Maintenance and care
8Using a Phillips screwdriver, install
the clip.
■Scheduled maintenance of the air
intake vent is necessary when
In some situations such as when the vehicle
is used frequently or in heavy traffic or dusty
areas, the air intake vent may need to be
cleaned more regularly.
For details, refer to “Owner’s Manual Sup-
plement” or “Scheduled Maintenance”.
■Cleaning the air intake vent
●Dust in the air intake vent may interfere
with the cooling of the hybrid battery
(traction battery). If charging/discharging
of the hybrid battery (traction battery)
becomes limited, the distance that the
vehicle can be driven using the electric
motor (traction motor) may be reduced
and the fuel economy may be reduced.
Inspect and clean the air intake vent peri-
odically.
●Improper handling of the air intake vent
cover and filter may result in damage to
them. If you have any concerns about
cleaning the filter, contact your Lexus
dealer.
■If “Maintenance required for Traction
battery cooling parts See owner’s man-
ual” is displayed on the multi-informa-
tion display
●If this warning message is displayed on
the multi-information display, remove the
air intake vent cover and clean the filter.
(  P.343)
●After cleaning the air intake vent, start
the hybrid system and check that the
warning message is no longer displayed.
After the hybrid system is started, it may be necessary to drive the vehicle up to
approximately 20 minutes before the
warning message disappears. If the warn-
ing message does not disappear after
driving for appropriately 20 minutes,
have the vehicle inspected by your Lexus
dealer.
WARNING
■When cleaning the air intake vent
●Do not use water or other liquids to
clean the air intake vent. If water is
applied to the hybrid battery (traction
battery) or other components, a mal-
function or fire may occur.
●Before cleaning the air intake vent,
make sure to turn the power switch off
to stop the hybrid system.
■When removing the air intake vent
cover
Do not touch the service plug located
near the air intake vent. ( P.64)
NOTICE
■When cleaning the air intake vent
When cleaning the air intake vent, make
sure to only use a vacuum to suck out
dust and clogs. If a compressed air blow
gun, etc. is used to blow out dust and
clogs, the dust or clogs may be pushed
into the air intake ve nt, which may affect
the performance of the hybrid battery
(traction battery) and cause a malfunc-
tion.