2020 LEXUS RX450H battery

5917-3. Do-it-yourself maintenance
7
Maintenance and care
RX350/RX350L_U
*: Vehicles with single-beam headlights
Tire inflation pres-
sure (P. 613)• Tire pressure gauge• Compressed air source
Washer fluid
( P. 603)• Water or washer fluid containing antifreeze (for winter use)
• Funnel (used only for adding water or washer fluid)
WARNING
The engine compartment contains many mechan isms and fluids that may move suddenly,
become hot, or become electrically energize d. To avoid death or serious injury, observe
the following precautions.
■When working on the engine compartment
●Keep hands, clothing and tools away from the moving fan and engine drive belt.
●Be careful not to touch the engine, radiator, exhaust manifold, etc. right after driving
as they may be hot. Oil and other fluids may also be hot.
●Do not leave anything that may burn easily, such as paper and rags, in the engine
compartment.
●Do not smoke, cause sparks or expose an open flame to fuel or the battery. Fuel and
battery fumes are flammable.
●Be extremely cautions when working on the battery. It contains poisonous and corro-
sive sulfuric acid.
■When working near the electric cooling fans or radiator grille
Be sure the engine switch is off.
With the engine switch in IGNITION ON mode, the electric cooling fans may auto-
matically start to run if the air conditioning is on and/or the coolant temperature is high.
(  P. 599)
■Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from getting in
your eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner f ilter removed may cause excessive engine wear due to dirt
in the air.
ItemsParts and tools

5947-3. Do-it-yourself maintenance
RX350/RX350L_U
Engine compartment
Washer fluid tank ( P. 603)
Engine oil filler cap ( P. 596)
Engine oil level dipstick (P. 595)
Engine coolant reservoir (P. 598) Battery
( P. 601)
Brake fluid reservoir ( P. 600)
Fuse box ( P. 625)
Radiator ( P. 599)
Condenser ( P. 599)
Electric cooling fans1
2
3
4
5
6
7
8
9
10

6017-3. Do-it-yourself maintenance
7
Maintenance and care
RX350/RX350L_U
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 precautions 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 charge r is off when connecting and disconnecting
the charger cables to the battery.
■After recharging/reconnecting the battery
●The engine may not start. Follow the pr ocedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the engine.
●Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the battery. If this happens, use the wireless
remote control or the mechanical key to lock/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 normally from
the second attempt.
●The engine switch mode is recorded by the vehicle. If the battery is reconnected, the
vehicle will return the engine switch mode to the status it was in before the battery was
disconnected. Make sure to turn off the power before disconnect the battery. Take
extra care when connecting the battery if the engine 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.
Battery
1
2
1
2
3

6027-3. Do-it-yourself maintenance
RX350/RX350L_U
WARNING
■Chemicals in the battery
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 wor king on or near the battery:
●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.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when working near the battery.
●Keep children away from the battery.
■Where to safely charge the battery
Always charge the battery in an open area . Do not charge the battery in a garage or
closed room where there is insufficient ventilation.
■How to recharge the battery
Only perform a slow charge (5 A or less) . The 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 there is insufficient battery fluid
Do not use if there is insufficient fluid in th e battery. There is a possible danger that the
battery may explode.
NOTICE
■When recharging the battery
Never recharge the battery while the engine is running. Also, be sure all accessories
are turned off.
■When adding distilled water
Avoid overfilling. Water spilled during battery recharging may cause corrosion.

6237-3. Do-it-yourself maintenance
7
Maintenance and care
RX350/RX350L_U
●Flathead screwdriver
●Lithium battery CR2032
Take out the mechanical key.
Remove the cover.
To prevent damage to the key, cover the
tip of the flathead screwdriver with a
tape.
Remove the depleted battery.
When removing the cover, the elec-
tronic key module may stick to the cover
and the battery may not be visible. In this
case, remove the el ectronic key module
in order to remove the battery.
Insert a new battery with the “+” termi-
nal facing up.
Electronic key battery
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
1
2
3

6247-3. Do-it-yourself maintenance
RX350/RX350L_U
■Use a CR2032 lithium battery
●Batteries can be purc hased 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 the 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.

643
8When trouble arises
RX350/RX350L_U
8-1. Essential informationEmergency flashers .................. 644
If your vehicle has to be stopped in
an emergency .......................... 645
8-2. Steps to take in an emergency
If your vehicle needs to be towed................................ 646
If you think something is wrong ........................................... 652
Fuel pump shut off system .......................................... 653
If a warning light turns on or a warning buzzer
sounds.......................................... 654
If a warning message is displayed...................................... 661
If you have a flat tire .................. 666
If the engine will not start ........ 682
If the electronic key does not operate properly .............684
If the vehicle battery is discharged ................................. 687
If your vehicle overheats ......... 692
If the vehicle becomes stuck ............................................. 695

644
RX350/RX350L_U8-1. Essential information
Press the switch.
All the turn signal lights will flash. To turn
them off, press the switch once again.
■Emergency flashers
If the emergency flashers are used for a long time while the engine is not operating, the
battery may discharge.
Emergency flashers
The emergency flashers are used to warn other drivers when the vehicle has
to be stopped on the road due to a breakdown, etc.