2018 LEXUS RX450h warning light

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

616 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U■
Situations in which the tire pressure warning system may not operate properly ●
In the following cases, the tire pressure warning system may not operate properly.
• If non-genuine Lexus wheels are used.
• A tire has been replaced with a tire that is not an OE (Original Equipment) tire.
• A tire has been replaced with a tire that is not of the specified size.
• Tire chains, etc. are equipped.
• If a window tint that affects th e radio wave signals is installed.
• If there is a lot of snow or ice on the vehi cle, particularly around the wheels or wheel
housings.
• If the tire inflation pressure is extr emely higher than the specified level.
• If wheel without the tire pressure warning valve and transmitter is used.
• If the ID code on the tire pressure warning valves and transmitters is not registered
in the tire pressure warning computer. ●
Performance may be affected in the following situations.
• Near a TV tower, electric power plant, gas station, radio station, large display, air-
port or other facility that generates st rong radio waves or electrical noise.
• When carrying a portable radio, cellular phone, cordless phon e or other wireless
communication device.
If tire position information is not correctl y displayed due to the radio wave conditions,
the display may be corrected by driving and changing the radio wave conditions. ●
When the vehicle is parked, the time taken for the warning to start or go off could be
extended. ●
When tire inflation pressure declines rapidly for example when a tire has burst, the
warning may not function. ■
The initialization operation ●
Make sure to carry out initialization afte r adjusting the tire inflation pressure.
Also, make sure the tires are cold before carryi ng out initialization or tire inflation pres-
sure adjustment. ●
If you have accidentally turned the power switch off during in itialization, it is not neces-
sary to press the reset switch again as initialization will re start automatically when the
power switch has been turned to ON mode for the next time. ●
If you accidentally press the re set switch when initialization is not necessary, adjust the
tire inflation pressure to the specified leve l when the tires are co ld, and conduct initial-
ization again. ●
While the position of each tire is being de termined and the inflation pressures are not
being displayed on the multi-info rmation display, if the inflat ion pressure of a tire drops,
the tire pressure warning light will come on.

6177-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Warning performance of the tire pressure warning system
The warning of the tire pressu re warning system will change in accordance with the con-
ditions under which it was init ialized. For this reason, the sy stem may give a warning even
if the tire pressure does not reach a low enough level, or if the pressu re is higher than the
pressure that was adjusted to when the system was initialized. ■
When initialization of the tire pressure warning system has failed
Initialization may take longer to complete if the vehicle is driven on an unpaved road.
When performing initialization, drive on a pa ved road if possible. Depending on the driv-
ing environment and condition of the tires, initialization wi ll be completed in approxi-
mately 10 to 30 minutes. If initialization is not complete after driving approximately 10 to
30 minutes, continue driving for a while.
If the inflation pressure of each tire is not displayed after driving fo r approximately 1 hour,
perform the following procedure. ●
Park the vehicle in a safe place for approxim ately 20 minutes. Then drive straight (with
occasional left and right turns) at appr oximately 25 mph (40 km/h) or more for
approximately 10 to 30 minutes.
However, in the following situations, the tire inflation pressure will not be recorded and
the system will not operate proper ly. Perform initialization again.●
When operating the tire pres sure warning reset switch, th e tire pressure warning light
does not blink 3 times. ●
After performing initia lization, the tire pressure warning light blinks for 1 minute then
stays on while driving.
If the inflation pressure of ea ch tire is still not displayed, have the vehicle inspected by
your Lexus dealer.

6197-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85UWARNING ■
When inspecting or replacing tires
Observe the following precautions to prevent accidents.
Failure to do so may cause damage to parts of the drive train as well as dangerous han-
dling characteristics, which may lead to an accident resu lting in death or serious injury.●
Do not mix tires of different makes, models or tread patterns.
Also, do not mix tires of remarkably different treadwear. ●
Do not use tire sizes other than those recommended by Lexus. ●
Do not mix differently constructed tires (radial, bias-belted or bias-ply tires). ●
Do not mix summer, all season and snow tires. ●
Do not use tires that have be en used on another vehicle.
Do not use tires if you do not know how they were used previously. ●
Do not tow if your vehicle has a compact spare tire installed. ■
When initializing the tire pressure warning system
Do not initializing tire inflatio n pressure without first adjusting the tire inflation pressure
to the specified level. Otherwise, the tire pressure warning light may not come on even
if the tire inflation pressure is low, or it may come on when the tire inflation pressure is
actually normal.
NOTICE ■
Repairing or replacing tires, wheels, tire pressure warning valv es, transmitters and
tire valve caps ●
When removing or fitting the wheels, tires or the tire pressure warning valves and
transmitters, contact your Lexus dealer as the tire pressure warning valves and trans-
mitters may be damaged if not handled correctly. ●
Make sure to install the tire valve caps. If the tire valve caps ar e not installed, water
could enter the tire pressure warning valves and the tire pressure warning valves
could be bound. ●
When replacing tire valve caps, do not use tire valve caps other than those specified.
The cap may become stuck. ■
To avoid damage to the tire pressu re warning valves and transmitters
When a tire is repaired with liquid sealants, the tire pressure warning valve and trans-
mitter may not operate properly. If a liquid sealant is used, contact your Lexus dealer or
other qualified service shop as soon as possi ble. Make sure to replace the tire pressure
warning valve and transmitter when replacing the tire. ( → P. 612)■
Driving on rough roads
Take particular care when driving on roads with loose surfaces or potholes.
These conditions may cause lo sses in tire inflation pre ssure, reducing the cushioning
ability of the tires. In addition, driving on rough roads may cause damage to the tires
themselves, as well as the vehicle’s wheels and body. ■
If tire inflation pressure of ea ch tire becomes low while driving
Do not continue driving, or your tires and/or wheels may be ruined.

634 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85UCheck if the fuse is blown.
Normal fuse
Blown fuse Replace the blown fuse with a new
fuse of an appropriate amperage rat-
ing. The amperage rating can be
found on the fuse box lid.
Many types of fuse are used on this
vehicle. This illustration shows a com-
mon type of fuse used on this vehicle.■
After a fuse is replaced ●
If the lights do not turn on even after the fuse has been replaced, a bulb may need
replacement. ( → P. 637)●
If the replaced fuse blows again, have th e vehicle inspected by your Lexus dealer.■
If there is an overload in a circuit
The fuses are designed to blow, protec ting the wiring ha rness from damage.■
When replacing light bulbs
Lexus recommends that you use genuine Lexus products designed for this vehicle.
Because certain bulbs are conne cted to circuits designed to prevent overload, nongenu-
ine parts or parts not designed for this vehicle may be unusable. 4
1
2
WARNING ■
To prevent system breakdowns and vehicle fire
Observe the following precautions.
Failure to do so may cause damage to th e vehicle, and possibly a fire or injury.●
Never use a fuse of a higher amperage rating than that indicated, or use any other
object in place of a fuse. ●
Always use a genuine Lexus fuse or equivalent.
Never replace a fuse with a wi re, even as a temporary fix.●
Do not modify the fuses or fuse boxes. ■
Fuse box near the power control unit
Never check or replace the fuses as there are high volt age parts and wiring near the
fuse box.
Doing so may cause electric shock, re sulting in death or serious injury.
NOTICE ■
Before replacing fuses
Have the cause of electrical overload determined and repaired by your Lexus dealer as
soon as possible.

6497-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
LED lights
The headlight low beams, headlight high beams, front turn signal lights (vehicles with tri-
ple-beam headlights), parking lights and da ytime running lights, fog lights, cornering
lights (if equipped), front side marker lights (vehicles with triple-b eam headlights), side
turn signal lights, stop/tail lights, rear turn signal light (vehicles with triple-beam head-
lights), rear side marker lights, high mounted stoplight, license plate lights, and outer foot
lights consist of a number of LEDs. If any of the LEDs has burned out, take your vehicle to
your Lexus dealer to have the light replaced. ■
Condensation build-up on the inside of a lens
Temporary condensation build-up on the inside of the headlight lens does not indicate a
malfunction. Contact your Lexus dealer for mo re information in the following situations:●
Large drops of water have built up on the inside of a lens. ●
Water has built up inside a headlight. ■
When replacing light bulbs
→ P. 634
WARNING ■
To prevent injury
Before performing any light bulb replacement procedure, be sure to turn the power
switch off. Failure to do so may result in burns from hot components or a part of your
body may get caught on an operating co mponent, possibly causing serious injury.■
Replacing light bulbs ●
Turn off the lights. Do not attempt to replac e the bulb immediately after turning off the
lights.
The bulbs become very hot and may cause burns. ●
Do not touch the glass portion of the light bu lb with bare hands. When it is unavoid-
able to hold the glass portion, use and hold with a clean dry cloth to avoid getting
moisture and oils on the bulb.
Also, if the bulb is sc ratched or dropped, it may blow out or crack.●
Fully install light bulbs and any parts used to secure them. Failure to do so may result
in heat damage, fire, or water entering th e headlight unit. This may damage the head-
lights or cause condensation to build up on the lens.●
Do not attempt to repair or disassemble th e light bulbs, connector s, electric circuits
or component parts.
Doing so may result in death or se rious injury due to electric shock.■
To prevent damage or fire ●
Make sure bulbs are fully seated and locked. ●
Check the wattage of the bulb before installing to prevent heat damage.

651
8When trouble arises
RX450h_RX450hL _U_OM48F85U 8-1. Essential information
Emergency flashers .................. 652
If your vehicle has
to be stopped in
an emergency .......................... 653
8-2. Steps to take in
an emergency
If your vehicle needs
to be towed................................ 654
If you think something is
wrong ........................................... 659
If a warning light turns on
or a warning buzzer
sounds..........................................660
If a warning message is
displayed..................................... 667
If you have a flat tire .................. 673
If the hybrid system will
not start .......................................690
If the electronic key does
not operate properly ............. 692
If the 12-volt battery is
discharged ................................. 695
If your vehicle overheats ......... 702
If the vehicle becomes
stuck ............................................. 706