warning LEXUS RX450h 2018 Owners Manual

6157-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Maximum load of tire
Check that the maximum load of the replacement tire is greater than 1/2 of the Gross
Axle Weight Ratings (GAWR) of either the front axle or the rear axle, whichever is
greater.
■
Tire types ●
Summer tires
Summer tires are high-speed performance ti res best suited to highway driving under
dry conditions. Since summer tires do not have the same traction performance as
snow tires, summer tires are inadequate for driving on snow-covered or icy roads. For
driving on snow-covered roads or icy road s, the use of snow tires is recommended.
When installing snow tires, be sure to replace all four tires.●
All season tires
All season tires are designed to provide better traction in snow and to be adequate for
driving in most winter conditions as well as for use year-round. All season tires, how-
ever, do not have adequate traction perfor mance compared with snow tires in heavy
or loose snow. Also, all season tires fall short in acceleration and handling perfor-
mance compared with summer tires in highway driving.●
Snow tires
For driving on snow-covered roads or icy roads, we recommend using snow tires. If
you need snow tires, select ti res of the same size, construction and load capacity as the
originally installed tires. Since your vehicle has radial tires as or iginal equipment, make
sure your snow tires also have radial cons truction. Do not install studded tires without
first checking local regulations for possible restrictions. Snow tires should be installed
on all wheels. ( → P. 390)■
Initializing the tire pressure warning system
Initialize the system with the tire inflation pressure adjusted to the specified level.■
If the tread on snow tires wears down below 0.16 in. (4 mm)
The effectiveness of the tire s as snow tires is lost.■
If you press the tire pressure warning reset switch accidentally
If initialization is performed, adjust the tire inflation pressure to the specified level and ini-
tialize the tire pressure warning system again. For the GAWR, see the Ce rtification Label. For
the maximum load of the tire, see the load limit
at maximum cold tire inflation pressure men-
tioned on the sidewall of the tire. ( → P. 723)

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.

618 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U■
Certification for tire pressure warning system
Except for vehicles sold in Canada 
For vehicles sold in Canada

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.

622 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U■
Instructions for checking tire inflation pressure
When checking tire in flation pressure, ob serve the following:●
Check only when the tires are cold.
If your vehicle has been parked for at least 3 hours or has not been driven for more than
1 mile or 1.5 km, you will get an accurate cold tire inflation pressure reading. ●
Always use a tire pressure gauge.
It is difficult to judge if a tire is properly inflated based only on its appearance. ●
It is normal for the tire inflat ion pressure to be higher after driving as heat is generated
in the tire. Do not reduce tire inflation pressure after driving.●
Never exceed the vehicle capacity weight.
Passengers and luggage weight should be placed so that the vehicle is balanced.
WARNING ■
Proper inflation is critical to save tire performance
Keep your tires properly inflated.
If the tires are not properly inflated, the following conditions may occur which could
lead to an accident resultin g in death or serious injury:●
Excessive wear ●
Uneven wear ●
Poor handling ●
Possibility of blowouts resu lting from overheated tires●
Air leaking from between tire and wheel ●
Wheel deformation and/or tire damage ●
Greater possibility of tire damage while driving (due to road hazards, expansion
joints, sharp edges on the road, etc.)
NOTICE ■
When inspecting and adjust ing tire inflation pressure
Be sure to put the tire valve caps back on.
If a valve cap is not installed, dirt or moisture may get into the valve and cause an air
leak, resulting in decreased tire inflation pressure.

6237-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85UWhen replacing wheels, care should be ta ken to ensure that they are equivalent
to those removed in load capacity, diameter, rim width and inset
* .
Replacement wheels are available at your Lexus dealer.
* : Conventionally referre d to as “offset”.
Lexus does not recommend using the following:●
Wheels of different sizes or types ●
Used wheels ●
Bent wheels that have been straightened ●
Use only Lexus wheel nuts and wrenches designed for use with your alumi-
num wheels. ●
When rotating, repairing or changing your tires, check that the wheel nuts are
still tight after driving 1000 miles (1600 km). ●
Be careful not to damage the aluminum wheels when using tire chains. ●
Use only Lexus genuine balance weights or equivalent and a plastic or rubber
hammer when balancing your wheels. ■
When replacing wheels
The wheels of your vehicle are equipped with tire pressure warning valves and transmit-
ters that allow the tire pressure warning system to provide advance warning in the event
of a loss in tire inflation pressure. Whenever wheels are replaced, tire pressure warning
valves and transmitters must be installed. ( → P. 612)Wheels If a wheel is bent, cracked or heavily corroded, it should be replaced. Other-
wise, the tire may separate from the wheel or cause a loss of handling control.
Wheel selection
Aluminum wheel precautions

624 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85UWARNING ■
When replacing wheels ●
Do not use wheels that are a different size from those recommended in the Owner’s
Manual, as this may result in a loss of handling control. ●
Never use an inner tube in a leaking wheel which is designed for a tubeless tire. Doing
so may result in an accident, causing death or serious injury. ■
Use of defective wheels prohibited
Do not use cracked or deformed wheels.
Doing so could cause the tire to leak air du ring driving, possibly causing an accident.
NOTICE ■
Replacing tire pressure warn ing valves and transmitters●
Because tire repair or replacement may affe ct the tire pressure warning valves and
transmitters, make sure to have tires serviced by your Lexus dealer or other qualified
service shop. In addition, ma ke sure to purchase your tire pressure warning valves
and transmitters at your Lexus dealer. ●
Ensure that only genuine Lexus wh eels are used on your vehicle.
Tire pressure warning valves and transmitte rs may not work properly with non-genu-
ine wheels. ■
Selectable Color Trim (if equipped) ●
If rattles, noise, or ot her problems occur while
Selectable Color Trim are installed, contact
your Lexus dealer. ●
Do not remove or install Selectable Color
Trim yourself, as it may be damaged. Have the
Selectable Color Trim removed and installed
by your Lexus dealer.

6317-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
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.

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.