2018 LEXUS RX450h ECU

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.

656 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UTake out the towing eyelet. ( → P. 674)
Remove the eyelet cover.
Insert the towing eyelet into the hole
and tighten partially by hand.
Tighten down the towing eyelet
securely using a wheel nut wrench
or hard metal bar.
Securely attach cables or chains to the towing eyelet.
Take care not to damage the vehicle body.
Enter the vehicle being towed and start the hybrid system.
If the hybrid system does not start, turn the power switch to ON mode.
Shift the shift lever to N and release the parking brake.
When the shift lever cannot be shifted: → P. 250Emergency towing procedure (vehicles with a towing eyelet) 1
2
3
4
5
6
7

6578-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U■
While towing
If the engine is not running, the power assist for the brakes and steering will not function,
marking steering and braking more difficult. ■
Wheel nut wrench
Wheel nut wrench is installe d in luggage compartment. ( → P. 674)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
When towing the vehicle
■
While towing ●
When towing using cables or chains, avoid sudden starts, etc. which place excessive
stress on the towing eyelets, cables or chains. The towing eyelets, cables or chains
may become damaged, broken debris ma y hit people, and cause serious damage.●
Do not turn the power switch off.
There is a possibility that the steering wheel is locked and cannot be operated.■
Installing towing eyelets to the vehicle
Make sure that towing eyel ets are installed securely.
If not securely installed, towing ey elets may come loose during towing.Be sure to transport the vehicle with all four
wheels raised off the ground. If the vehicle is
towed with the tires contacting the ground, the
drivetrain or related parts may be damaged,
the vehicle may fly off th e truck, or electricity
generated by the operation of the motor may
cause a fire to occur depending on the nature
of the damage or malfunction.

658 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UNOTICE ■
To prevent damage to the vehicle when towing using a wheel-lift type truck●
Do not tow the vehicle from the rear when the power switch is off. The steering lock
mechanism is not strong enough to hold the front wheels straight. ●
When raising the vehicle, en sure adequate ground cleara nce for towing at the oppo-
site end of the raised vehicle. Without ad equate clearance, the vehicle could be dam-
aged while being towed. ■
To prevent damage to the vehicle wh en towing with a sling-type truck
Do not tow with a sling-type truck, either from the front or rear. ■
To prevent damage to the ve hicle during emergency towing
Do not secure cables or chains to the suspension components. ■
Recreational towing (behind motor home, etc)
Never dinghy tow your vehicle to prevent caus-
ing serious damage to the Hybrid AWD system
and transmission. ( → P. 238)

664 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact se nsors (rear), driver’s seat position sensor,
driver’s seat belt buckle sw itch, front passenger occupant classification system (ECU and
sensors), “AIR BAG ON” indicator light, “A IR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, driver’s seat belt pretension er, front passenger’s seat belt
pretensioner and force limiter, airbags, in terconnecting wiring and power sources.
( → P. 36) ■
Front passenger detection sensor, seat belt reminder and warning buzzer●
If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sittin g in the seat.●
If a cushion is placed on the seat, the sens or may not detect a passenger, and the warn-
ing light may not operate properly. ■
Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insu fficient or the voltage temporarily drops,
the electric power steering system warning light may come on and the warning buzzer
may sound. ■
If the malfunction indicator lamp comes on while driving
First check the following: ●
Is the fuel tank empty?
If it is, fill the fu el tank immediately.●
Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after severa l trips, contact your Lexus dealer as soon as
possible. ■
When the tire pressure warning light comes on
Inspect the tires to check if a tire is punctured.
If a tire is punctured: → P. 673
If none of the tires are punctured:
Turn the power switch off then turn it to ON mode. Check if the tire pressure warning
light comes on or blinks. 
If the tire pressure warning light comes on
After the temperature of the tires has lowere d sufficiently, check the inflation pressure
of each tire and adjust th em to the specified level.
If the warning light does not turn off even after several minutes have elapsed, check
that the inflation pressure of each tire is at the specified level an d perform initialization.
( → P. 613)
If the warning light does not turn off severa l minutes after the init ialization has been per-
formed, have the vehicle inspected by your Lexus dealer immediately. 
If the tire pressure wa rning light blinks for 1 minute then stays on
There may be a malfunction in the tire pressure warnin g system. Have the vehicle
inspected by your Lexus dealer immediately. 1
2

678 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85USecure the deck board using the hook. ( → P. 544)
Disengage the hook and take out
the jack. RX450h: Remove the wheel nut
wrench and then the jack
RX450hL: Remove th e jack handle and
then the jack 
RX450h
Secure the deck board using the hook. ( → P. 544)
Remove the spare tire cover.
Loosen the center fastener that
secures the spare tire.Taking out the jack 1
2
Taking out the spare tire 1
2
3

688 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UWARNING ■
When using the compact spare tire ●
Remember that the compact spare tire provid ed is specifically designed for use with
your vehicle. Do not use your comp act spare tire on another vehicle.●
Do not use more than one comp act spare tire simultaneously.●
Replace the compact spare tire with a standard tire as soon as possible.●
Avoid sudden acceleration, abrupt steering, sudden braking and shifting operations
that cause sudden engine braking. ■
When the compact spare tire is attached
The vehicle speed may not be correctly detected, and the following systems may not
operate correctly:
Also, not only can the following system not be utilized fully, but it may even negatively
affect the drive-train components:
•E-Four ■
Speed limit when using the compact spare tire
Do not drive at speeds in excess of 50 mph (80 km/h) when a compact spare tire is
installed on the vehicle.
The compact spare tire is not designed for driving at high speeds. Failure to observe
this precaution may lead to an accid ent causing death or serious injury.■
After using the tools and jack
Before driving, make sure all the tools and jack are securely in place in their storage
location to reduce the possibilit y of personal injury during a collision or sudden brak-
ing.• ABS & Brake assist
•VSC
•TRAC
•EPS
• Trailer Sway Control
•VDIM
• Adaptive Variable Suspension System
(if equipped)
• Dynamic radar cruise control with full-
speed range
• PCS (Pre-Collision System)
• LKA (Lane-Keeping Assist) • Automatic High Beam
• AFS (Adaptive Front-lighting System)
(if equipped)
• Tire pressure warning system
• Intuitive parking assist (if equipped)
• Intelligent Clearance Sonar (ICS) (if
equipped)
• Lexus parking assist monitor (if
equipped)
• Panoramic view monitor (if equipped)
• BSM (Blind Spot Monitor) (if
equipped)
• Navigation system (if equipped)

6898-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UNOTICE ■
Be careful when driving over bumps with th e compact spare tire installed on the vehi-
cle
When driving with the compact spare tire installed, the vehi cle height will be different
than when driving with standard tires. Be careful when driving over uneven road sur-
faces, etc. ■
Driving with tire chains and the compact spare tire
Do not fit tire chains to the compact spare tire.
Tire chains may damage the vehicle body and adversely affect driving performance.■
When replacing the tires
When removing or fitting the wheels, tires or the tire pressure warning valve and trans-
mitter, contact your Lexus dealer as the tire pressure warning valve and transmitter
may be damaged if not handled correctly. ■
When stowing the flat tire (RX450hL) ●
Ensure that there is no object caught between the tire and the vehicle underbody. ●
Securely tighten the spare tire clamp bolt to hold the spare wheel carrier by the hook. ●
Stow the flat tire in the spare tire location. Failure to do so may cause damage to the
spare tire carrier. Pr oper storage reduces the possibilit y of injury in a collision or
during sudden braking. ●
Have the flat tire repaired and the spare tire replaced with it as soon as possible. ■
Proper storage of the spare tire (RX450hL)
●
If the spare tire clamp bolt is turned withou t a tire on the hoist assembly, the wire cable
may not be able to be lowered. If the wire cable cannot be lowered, contact your
Lexus dealer. ●
If the hoist assembly is slanted when stowing a
tire, the hoist assembly may become stuck in
the wheel opening and the tire may not be
raised properly, causing damage to the wheel
or the wire cable.