2018 LEXUS RX450h maintenance

6077-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U 
RX450h
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps.
Terminals
Hold-down clamp 
RX450hL
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps.
Terminals
Hold-down clampExterior 1
2
1
2

608 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U 
RX450h
Install the 12-volt battery cover with the
clips.
Push up center position
Insert
Press 
RX450hL
Install the deck side trim cover.
Install the 12-volt battery cover.Installing the 12-volt battery cover 1
2
3
1
2

6097-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Before recharging
When recharging, the 12-volt battery produc es 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 the 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 mo de. 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 vehicle. 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
battery was disconnected. Make sure to turn off the power before disconnect the 12-
volt battery. Take extra care when connec ting 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.
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 matc h 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. 1
2
3

610 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85UWARNING ■
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 handling the 12-volt battery
→ P. 700 ■
When disconnecting the 12-volt battery (RX450h)
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.Do not disconnect the negative (-) terminal on
the body side as shown. The disconnected neg-
ative (-) terminal may touch the positive (+) ter-
minal, which may cause a short and result in
death or serious injury.

6117-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85UCheck if the treadwear indicators are showing on the tires. Also check the tires
for uneven wear, such as excessive wear on one side of the tread.
Check the spare tire condition and pressure if not rotated.
New tread
Worn tread
Treadwear indicator The location of treadwear indica tors is shown by a “TWI” or “ Δ ” mark, etc., molded
into the sidewall of each tire.
Replace the tires if the treadwear indicators are showing on a tire.
Rotate the tires in the order shown. To equalize tire wear and extend tire life,
Lexus recommends that tire rotation is
carried out at the same interval as tire
inspection.
Do not fail to initialize the tire pressure
warning system after tire rotation.Tires Replace or rotate tires in accordance with maintenance schedules and tread-
wear.
Checking tires
Tire rotation 1
2
3
Front

612 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85UYour vehicle is equipped with a tire pressure warning system that uses tire pres-
sure warning valves and transmitters to detect low tire inflation pressure before
serious problems arise.
◆ Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pr essure warning valv es and transmitters
must also be installed.
When new tire pressure wa rning valves and transmitters are installed, new ID
codes must be registered in the tire pressure warning computer and the tire
pressure warning system must be initia lized. Have tire pressure warning valve
and transmitter ID codes registered by your Lexus dealer. ( → P. 613)
◆ Initializing the tire pressure warning system ■
The tire pressure warning system must be initialized in the following circum-
stances: ●
When the tire inflation pressure is changed such as when changing travel-
ing speed. ●
When the tire inflation pressure is changed such as when the tire size is
changed. ●
When rotating the tires
When the tire pressure warning system is initialized, the current tire inflation
pressure is set as the benchmark pressure.Tire pressure warning system ●
The tire pressure detected by the tire
pressure warning system can be dis-
played on the multi-information display. The illustration used is intended as an exam-
ple, and may differ from the image that is
actually displayed on the multi-information
display.●
If the tire pressure drops below a prede-
termined level, the driver is warned by a
screen display and a warning light.
( → P. 662) The illustration used is intended as an exam-
ple, and may differ from the image that is
actually displayed on the multi-information
display.

6137-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the power switch off. Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to th e specified cold tire inflation pressure
level. ( → P. 717)Make sure to adjust the tire pressure to the specified cold tire inflation pressure
level. The tire pressure warning system will operate based on this pressure level.
Turn the power switch to ON mode.
Select on the multi-information display. ( → P. 108)
Press or of the meter control sw itch, select the “Vehicle Settings”
screen and then press the .
Press or of the meter con-
trol switch, select the “TPMS”
screen and then press and hold
the
until the tire pressure
warning light blinks slowly 3
times. “- -” will be displayed for inflation
pressure of each tire on the multi-
information displa y while the tire
pressure warning system determines
the position of each tire.
When position of each tire is determined, the inflation pressure of each tire will be
displayed on the mult i-information display.
Drive the vehicle at approximately 25 mph (40 km/h) or more for approx-
imately 10 to 30 minutes until the inflat ion pressure of each tire is displayed
on the multi-information display. If tire inflation pressure becomes low before the inflation pressure is displayed, the
tire pressure warning light will come on.
Depending on the vehicle and driving co nditions, initialization may take up to
approximately 1 hour to complete.
◆ Registering ID codes
The tire pressure warning valve and tran smitter is equipped with a unique ID
code. When replacing a tire pressure warning valve and transmitter, it is nec-
essary to register the ID code. Have the ID code registered by your Lexus
dealer. 1
2
3
4
5
6
7

614 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U■
When to replace your vehicle’s tires
Tires should be replaced if: ●
The treadwear indicators are showing on a tire. ●
You have tire damage such as cuts, splits, cracks deep enou gh to expose the fabric, and
bulges indicating internal damage. ●
A tire goes flat repeatedly or cannot be properly repaired due to the size or location of
a cut or other damage.
If you are not sure, consult with your Lexus dealer. ■
Replacing tires and wheels
If the ID code of the tire pressure warning valve and transmitter is not registered, the tire
pressure warning system will not work proper ly. After driving for about 20 minutes, the
tire pressure warning light blinks for 1 minu te and stays on to indicate a system malfunc-
tion. ■
Tire life
Any tire over 6 years old must be checked by a qualified technician even if it has seldom
or never been used or damage is not obvious.■
Proper storage of the spare tire (RX450hL)
As an improperly stored spare tire may cause damage to the wire cable that holds it,
check that the spare tire is stored properly on a daily basis.
If the spare tire is slanted, the hoist assemb ly may be stuck in the wheel opening. If the
spare tire rattles while driving, it may not be fully raised. Lower the spare tire to the
ground and make sure that the hoist assemb ly is perpendicular to the wheel opening.
Raise the tire slowly and steadily until a click is heard and the jack handle skips.
If the spare tire cannot be lowered, the wire cable may be severed. Have the vehicle
inspected at your Lexus dealer. ■
Routine tire inflation pressure checks
The tire pressure warning syst em does not replace routine tire inflation pressure checks.
Make sure to check tire inflat ion pressure as part of your routine of daily vehicle checks.●
If the stored spare tire appears to be slanted or
rattles while driving, the spare tire may not be
properly stored. Store the spare tire again by
performing the following tire change proce-
dure correctly: 1
2