check engine LEXUS RX450h 2018 Owners Manual

TABLE OF CONTENTS
6
RX450h_RX450hL _U_OM48F85U7-1. Maintenance and care
Cleaning and protecting
the vehicle exterior ................580
Cleaning and protecting
the vehicle interior.................. 584
7-2. Maintenance
Maintenance
requirements ............................ 587
General mainte nance..............589
Emission inspection and
maintenance (I/M)
programs.................................... 592
7-3. Do-it-yourself
maintenance
Do-it-yourself service
precautions................................ 593
Hood ............................................... 595
Positioning a floor jack ............ 596
Engine compartment ............... 597
12-volt battery ............................. 605
Tires .................................................... 611
Tire inflation pressure .............. 620
Wheels ........................................... 623
Air conditioning filter ............... 625
Windshield wiper inserts ........ 628
Electronic key battery.............. 630
Checking and replacing
fuses.............................................. 632
Headlight aim .............................. 635
Light bulbs .................................... 637 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 .........7067
Maintenance and care 8
When trouble arises

17Pictorial index
RX450h_RX450hL _U_OM48F85UWindshield wipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 267 Precautions against winter season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 390
To prevent freezing (windshield wiper de-icer)
* . . . . . . . . . . . . . . . . . . . . . . . . P. 516
Precautions against car wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 582
Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P . 274Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 276
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 712
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 611Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 717
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 39 0
Checking/rotation/tire pressure warning system . . . . . . . . . . . . . . . . . . . . . . . . P. 611
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 673
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 595Opening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 595
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 713
Coping with overheat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 702
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 2 52
Parking lights/daytime running lights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258
Front side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258
Fog lights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 266
Cornering lights
* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 259
Stop/tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258
Back-up lights Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 246
Rear side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 258 4
5
6
7
Light bulbs of the exte rior lights for driving
(Replacing method: P. 637, Watts: P. 719)
* : If equipped8
9
10
11
12
13
14
15
16
17

100 2. Instrument cluster
RX450h_RX450hL _U_OM48F85U■
Tachometer
Hybrid System Indicator switches to the tachometer when driving mode is in sport mode.
The settings of the tachometer display can be changed on of the multi-information
display. ( → P. 108)■
Engine speed
On hybrid vehicles, engine speed is precisel y controlled in order to help improve fuel
efficiency and reduce exhaust emissions etc.
There are times when the engine speed that is displayed may differ even when vehicle
operation and driving conditions are the same. ■
Brightness of the meters (d ay mode and night mode)
The brightness of the meters is changed between day mode and night mode. ●
Day mode: When the tail lights are off or when the tail lights are on but the surrounding
area is bright ●
Night mode: When the tail lights are on and the surrounding area is dark ■
Outside temperature display ●
In the following situations, the correct outside temperature may not be displayed, or the
display may take longer than normal to change:
• When stopped, or driving at low speeds (less than 12 mph [20 km/h])
• When the outside temperature has changed suddenly (at the entrance/exit of a
garage, tunnel, etc.) ●
When “ − − ” or “E” is displayed, the sy stem may be malfunctioning.
Take your vehicle to your Lexus dealer. ■
Clock settings screen (vehicles with a navigation system only)
If the clock adjustment screen is displayed continuously wh en attempting to change the
clock settings, the system may be malfunctioning.
Have the vehicle inspected by your Lexus dealer. ■
Customization
Some functions can be customized. ( → P. 108)
NOTICE ■
To prevent damage to the engine and its components●
Do not let the indicator needle of the tachometer enter the red zone, which indicates
the maximum engine speed. ●
The engine may be overheating if the engine coolant temperature gauge is in the red
zone (H). In this case, immediately stop the vehicle in a safe place, and check the
engine after it has cooled completely. ( → P. 702)

2154-1. Before driving
4
Driving
RX450h_RX450hL _U_OM48F85UWARNING
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
When driving the vehicle ●
During normal driving, do not turn off the hybrid system. Turning the hybrid system off
while driving will not cause loss of steering or braking control, however, power assist
to the steering will be lost. This will make it more difficult to steer smoothly, so you
should pull over and stop the vehicle as soon as it is safe to do so.
In the event of an emergency, such as if it becomes impossible to stop the vehicle in
the normal way: → P. 653●
Use engine braking (downshift) to maintain a safe speed when driving down a steep
hill.
Using the brakes continuously may cause th e brakes to overheat and lose effective-
ness. ( → P. 246)●
Do not adjust the positions of the steering wheel, the seat, or the inside or outside rear
view mirrors while driving.
Doing so may result in a loss of vehicle control. ●
Always check that all passengers’ arms, he ads or other parts of their body are not
outside the vehicle. ●
Do not drive the vehicle off-road.
This is not an AWD vehicle designed for of f-road driving. Proceed with all due cau-
tion if it becomes unavoidable to drive off-road. ●
Do not drive across a river or through other bodies of water.
This may cause electric/electronic componen ts to short circuit, damage the hybrid
system or cause other serious damage to the vehicle. ●
Do not drive in excess of the speed limit. Even if the legal speed limit permits it, do not
drive over 85 mph (140 km/h) unless your vehicle has high-speed capability tires.
Driving over 85 mph (140 km/h ) may result in tire failure , loss of control and possible
injury. Be sure to consult a tire dealer to determine whether the tires on your vehicle
are high-speed capability tires or no t before driving at such speeds.

2174-1. Before driving
4
Driving
RX450h_RX450hL _U_OM48F85UWARNING
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
If you hear a squealing or scraping noise (brake pad wear limit indicators)
Have the brake pads checked and replaced by your Lexus dealer as soon as possible.
Rotor damage may result if the pads are not replaced when needed.
It is dangerous to drive the vehicle when the wear limits of the brake pads and/or those
of the brake discs are exceeded. ■
When the vehicle is stopped ●
Do not depress the accelerator pedal unnecessarily.
If the shift lever is in any position other than P or N, the vehicle may accelerate sud-
denly and unexpectedly, causing an accident. ●
In order to prevent accidents due to the ve hicle rolling away, always keep depressing
the brake pedal while stopped with the “REA DY” indicator is illuminated, and apply
the parking brake as necessary. ●
If the vehicle is stopped on an incline, in order to prevent accidents caused by the
vehicle rolling forward or backward, alwa ys depress the brake pedal and securely
apply the parking brake as needed. ●
Avoid revving or r acing the engine.
Running the engine at high speed while the vehicle is stopped may cause the exhaust
system to overheat, which could result in a fire if combustible material is nearby.■
When the vehicle is parked ●
Do not leave glasses, cigarette lighters, sp ray cans, or soft drink cans in the vehicle
when it is in the sun.
Doing so may result in the following:
• Gas may leak from a cigarette lighter or spray can, and may lead to a fire.
• The temperature inside the vehicle may cau se the plastic lenses and plastic mate-
rial of glasses to deform or crack.
• Soft drink cans may fracture, causing the contents to spray over the interior of the
vehicle, and may also cause a short circui t in the vehicle’s electrical components.●
Do not leave cigarette lighters in the vehicle. If a cigarette lighter is in a place such as
the glove box or on the floor, it may be lit accidentally when luggage is loaded or the
seat is adjusted, causing a fire. ●
Do not attach adhesive discs to the windsh ield or windows. Do not place containers
such as air fresheners on th e instrument panel or dashbo ard. Adhesive discs or con-
tainers may act as lenses, ca using a fire in the vehicle.●
Do not leave a door or window open if th e curved glass is coated with a metallized
film such as a silver-colored one. Reflecte d sunlight may cause the glass to act as a
lens, causing a fire. ●
Always apply the parking brake, shift the shif t lever to P, stop the hybrid system and
lock the vehicle.
Do not leave the vehicle unattended whil e the “READY” indicator is illuminated.
If the vehicle is parked with the shift leve r in P but the parking brake is not set, the
vehicle may start to move, possibly leading to an accident. ●
Do not touch the exhaust pipes while the “R EADY” indicator is illuminated or imme-
diately after turning the hybrid system off.
Doing so may cause burns.

2194-1. Before driving
4
Driving
RX450h_RX450hL _U_OM48F85UNOTICE ■
When driving the vehicle ●
Do not depress the accelerator and brake pedals at the same time during driving, as
this may restrain driving torque. ●
Do not use the accelerator pedal or depre ss the accelerator and brake pedals at the
same time to hold the vehicle on a hill. ■
When parking the vehicle
Always set the parking brake and shift the shift lever to P. Failure to do so may cause the
vehicle to move or the vehicle may accelerate suddenly if the accelerator pedal is acci-
dentally depressed. ■
Avoiding damage to vehicle parts ●
Do not turn the steering wheel fully in either direction and hold it there for an
extended period of time.
Doing so may damage the power steering motor. ●
When driving over bumps on the road, drive as slowly as possible to avoid damaging
the wheels, underside of the vehicle, etc. ■
If you get a flat tire while driving
A flat or damaged tire may cause the following situations . Hold the steering wheel
firmly and gradually depress the brake pedal to slow down the vehicle. ●
It may be difficult to control your vehicle. ●
The vehicle will make abnormal sounds or vibrations. ●
The vehicle will lean abnormally.
Information on what to do in case of a flat tire ( → P. 673)■
When encountering flooded roads
Do not drive on a road that has flooded after heavy rain, etc. Doing so may cause the
following serious damage to the vehicle: ●
Engine stalling ●
Short in electrical components ●
Engine damage caused by water immersion
In the event that you drive on a flooded road and the vehicle is flooded, be sure to have
your Lexus dealer check the following: ●
Brake function ●
Changes in quantity and quality of oil and fluid used for the engine, hybrid transmis-
sion, rear differential, etc. ●
Lubricant condition for the bearings and su spension joints (where possible), and the
function of all joints, bearings, etc.

234 4-1. Before driving
RX450h_RX450hL _U_OM48F85U■
Break-in schedule
If your vehicle is new or equipped with any new power train components (such as an
engine, hybrid transmission, rear differenti al or wheel bearing), Lexus recommends that
you do not tow a trailer until the vehicle ha s been driven for over 500 miles (800 km).
After the vehicle has been driven for over 500 miles (800 km), you can start towing.
However, for the next 500 miles (800 km), drive the vehicle at a speed of less than
50 mph (80 km/h) when towing a trailer, and avoid full throttle acceleration.■
Maintenance ●
If you tow a trailer, your vehicle will requir e more frequent maintenance due to the addi-
tional load. (See “Warranty and Services Guide”, “Owner’s Manual Supplement” or
“Scheduled Maintenance”.) ●
Retighten the fixing bolts of the towing ba ll and bracket after approximately 600 miles
(1000 km) of trailer towing. ■
If trailer sway occurs
One or more factors (crosswinds, passing ve hicles, rough roads, etc.) can adversely
affect handling of your vehicle and trailer, causing instability. ●
If trailer swaying occurs:
• Firmly grip the steering wh eel. Steer straight ahead.
Do not try to control trailer sway ing by turning the steering wheel.
• Begin releasing the accelerator pedal im mediately but very gradually to reduce
speed.
Do not increase speed. Do not apply vehicle brakes.
If you make no extreme correction with the st eering or brakes, your vehicle and trailer
should stabilize. (if enabled, Trailer Sway Control can also he lp to stabilize the vehicle and
trailer.) ●
After the trailer sw aying has stopped:
• Stop in a safe place. Get all occupants out of the vehicle.
• Check the tires of the vehicle and the trailer.
• Check the load in the trailer.
Make sure the load has not shifted.
Make sure the tongue weight is appropriate, if possible.
• Check the load in the vehicle.
Make sure the vehicle is not ov erloaded after occupants get in.
If you cannot find any problems, the speed at which trailer swaying occurred is beyond
the limit of your particular vehicle-trailer combination.
Drive at a lower speed to prevent instability. Remember that swaying of the towing vehi-
cle-trailer increases as speed increases.

3894-6. Driving tips
4
Driving
RX450h_RX450hL _U_OM48F85U◆ Delays
Repeated acceleration and deceleration, as well as long waits at traffic lights,
will lead to bad fuel economy. Check traffic reports before leaving and avoid
delays as much as possible. When drivin g in a traffic jam, gently release the
brake pedal to allow the vehicle to move forward slightly while avoiding over-
use of the accelerator pedal. Doing so can help control excessive gasoline
consumption.
◆ Highway driving
Control and maintain the vehicle at a co nstant speed. Before stopping at a toll
booth or similar, allow plenty of ti me to release the accelerator and gently
apply the brakes. A greater amount of electrical energy can be regenerated
when slowing down.
◆ Air conditioning
Use the air conditioning only when necessary. Doing so can help reduce
excessive gasoline consumption.
In summer: When the ambient temperature is high, use the recirculated air
mode. Doing so will help to reduce the burden on the air conditioning system
and reduce fuel consumption as well.
In winter: Because the gasoline engine will not automatically cut out until it
and the interior of the vehicle are warm , it will consume fuel. Also, fuel con-
sumption can be improved by av oiding overuse of the heater.
◆ Checking tire inflation pressure
Make sure to check the tire inflation pr essure frequently. Improper tire infla-
tion pressure can cause poor fuel economy.
Also, as snow tires can cause large amou nts of friction, their use on dry roads
can lead to poor fuel economy. Use ti res that are appropriate for the season.
◆ Luggage
Carrying heavy luggage will lead to poor fuel economy. Avoid carrying
unnecessary luggage. Installing a large roof rack will also cause poor fuel
economy.
◆ Warming up before driving
Since the gasoline engine starts up an d cuts out automatically when cold,
warming up the engine is unnecessary. Moreover, frequently driving short dis-
tances will cause the engine to repeated ly warm up, which can lead to excess
fuel consumption.

390 4-6. Driving tips
RX450h_RX450hL _U_OM48F85U●
Use fluids that are appropriate to the prevailing outside temperatures.
•Engine oil
• Engine/power cont rol unit coolant
• Washer fluid ●
Have a service technician inspect the condition of the 12-volt battery. ●
Have the vehicle fitted with four snow tires or purchase a set of tire chains for
the front tires. Ensure that all tires are of the specified size and the same brand, and that chains
match the size of the tires.
Perform the following according to the driving conditions: ●
Do not try to forcibly open a window or move a wiper that is frozen. Pour
warm water over the frozen area to me lt the ice. Wipe away the water imme-
diately to prevent it from freezing. ●
To ensure proper operation of the c limate control system fan, remove any
snow that has accumulated on the air inlet vents in front of the windshield. ●
Check for and remove any excess ice or snow that may have accumulated on
the exterior lights, vehicle’s roof, chassi s, around the tires or on the brakes.●
Remove any snow or mud from the bottom of your shoes before getting in the
vehicle.Winter driving tips Carry out the necessary preparations an d inspections before driving the vehi-
cle in winter. Always drive the vehicle in a manner appropriate to the prevail-
ing weather conditions.
Pre-winter preparations
Before driving the vehicle

396 4-6. Driving tips
RX450h_RX450hL _U_OM48F85U [
WARNING ■
Off-road driving precautions
Always observe the following precautions to minimize the risk of death, serious injury
or damage to your vehicle: ●
Drive carefully when off the road. Do not ta ke unnecessary risks by driving in danger-
ous places. ●
Do not grip the steering wheel spokes when driving off-road. A bad bump could jerk
the wheel and injure your hands. Keep both hands and especially your thumbs on the
outside of the rim. ●
Always check your brakes for effectiveness immediately after driving in sand, mud,
water or snow. ●
After driving through tall grass, mud, rock , sand, rivers, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped on the underbody.
Clear off any such matter from the underbody. If the vehicle is used with these materi-
als trapped or adhering to the underbody, a breakdown or fire could occur. ●
When driving off-road or in rugged terrain , do not drive at excessive speeds, jump,
make sharp turns, strike obje cts, etc. This may cause loss of control or vehicle rollover
causing death or serious injury. You are also risking expensive damage to your vehi-
cle’s suspension and chassis.
NOTICE ■
To prevent water damage
Take all necessary safety measures to ensure that water damage to the hybrid battery
(traction battery), hybrid system or other components does not occur.●
Water entering the engine compartment may cause severe damage to the hybrid
system. Water entering the interior may cause the hybrid battery (traction battery)
stowed under the rear seats to short circuit.●
Water entering the hybrid transmission and rear electric motor (traction motor) will
cause deterioration in transmission qualit y. The malfunction indicator may come on,
and the vehicle may not be drivable. ●
Water can wash the grease from wheel be arings, causing rusting and premature fail-
ure, and may also enter the hybrid transmissi on case, reducing the gear oil’s lubricat-
ing qualities. ■
When you drive through water
If driving through water, such as when cro ssing shallow streams, first check the depth of
the water and the bottom of the riverbed for firmness. Drive slowly and avoid deep
water. ■
Inspection after off-road driving ●
Sand and mud that has accumulated around brake discs may affect braking efficiency
and may damage brake system components. ●
Always perform a maintenance inspection afte r each day of off-road driving that has
taken you through rough terrain, sand, mud, or water. For scheduled maintenance
information, refer to the “Warranty and Services Guide/Owner’s Manual Supple-
ment/Scheduled Maintenance”.