2018 Lexus ES300h battery

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ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
7
Maintenance and care
Engine compartment
■12-volt battery
→
P. 457
Washer fluid tank ( →P. 456)
Fuse boxes (→ P. 480)
Power control unit coolant
reservoir ( →P. 453)
Engine oil level dipstick (→P. 449)
Engine oil filler cap (→ P. 450)Engine coolant reservoir
(→P. 453)
Brake fluid reservoir ( →P. 455)
Power control unit coolant
radiator (→ P. 454)
Electric cooling fans
Condenser ( →P. 454)
Engine coolant radiator (→P. 454)1
2
3
4
5
6
7
8
9
10
11

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ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
7
Maintenance and care
12-volt battery
The 12-volt battery is located on the
right-hand side of trunk.
Remove the 12-volt battery cover.
Install the cover
Lift the tab to secure to the trunk
liner
Location
Removing the 12-volt battery cover
Installing the 12-volt battery cover
1
2

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ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose cl
amps. Make sure that the terminal cov-
ers are secured over the battery terminals.
Terminals
Hold-down clamp
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging:
●If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the charge r is off when connecting and disconnecting
the charger cables to the 12-volt battery.
■After recharging/reconnecting the 12-volt battery
●The hybrid system may not start. Follow th e procedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system.
●Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mechan ical key to lock/unlock the doors.
●Start the hybrid system with the power sw itch in ACCESSORY mode. The hybrid sys-
tem 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 v ehicle. If the 12-volt battery is reconnected,
the vehicle will return the power switch mode to the status it was in before the 12-volt bat-
tery was disconnected. Make sure to turn o ff 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 system will not start even after multip le attempts at all methods above, contact your
Lexus dealer.
Exterior
1
2
1
2
3

ES300h_OM_OM33D45U_(U)
4597-3. Do-it-yourself maintenance
7
Maintenance and care
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions 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 battery in
a garage or closed room where th ere is insufficient ventilation.
■How to recharge the 12-volt battery
Only perform a slow charge (5 A or less). The 12-volt battery may explode if charged
at a quicker rate.
■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 fe el pain or burning, get medical attention
immediately.
●If electrolyte gets on your clothes
It can soak through clothing on to your s kin. Immediately take off the clothing and fol-
low the procedure above if necessary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergenc y medical attention immedi-
ately.
■When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause gas (hydro-
gen) to enter the passenger compartment, causing a fire or explosion.
For replacement of the 12-volt battery, contact your Lexus dealer.

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ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
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.

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ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
Electronic key battery
●Flathead screwdriver
●Small flathead screwdriver
●Lithium battery CR2032
Take out the mechanical key.
Remove the cover.
To prevent damage to the key, cover the
tip of the screwdriver with a rag.
Remove the depleted battery.
Insert a new battery with the “+” termi-
nal facing up.
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
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ES300h_OM_OM33D45U_(U)
4797-3. Do-it-yourself maintenance
7
Maintenance and care
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus dealer, loca l 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.
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-button start and wireless remote control will not
function properly.
●The operational rang e will be reduced.
WARNING
■Removed battery and other parts
These parts are small and if swallowed by a child, they can cause choking. Keep away
from children. Failure to do so coul d result in death or serious injury.
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 co mponent inside the remote control.
●Do not bend either of the battery terminals.

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ES300h_OM_OM33D45U_(U)
8When trouble arises
8-1. Essential informationEmergency flashers .................. 496
If your vehicle has to be stopped in an emergency.... 497
8-2. Steps to take in an emergency If your vehicle needs to be towed................................498
If you think something is wrong ................502
If a warning light turns on or a warning buzzer sounds.....503
If a warning message is displayed ................................509
If you have a flat tire ................... 513
If the hybrid sy stem will not
start ............................................... 523
If the electronic key does not operate properly ..................... 525
If the 12-volt battery is discharged ................................. 527
If your vehicle overheats .......... 531
If the vehicle becomes stuck .............................................535