engine overheat LEXUS RX450h 2021 Owners Manual

4TABLE OF CONTENTS
6-1. Maintenance and careCleaning and protecting the vehi-cle exterior ................................... 356
Cleaning and protecting the vehi- cle interior .................................... 359
6-2. Maintenance Maintenance requirements ..... 362
General maintenance ................ 363
Emission inspection and mainte- nance (I/M) programs ............ 366
6-3. Do-it-yourself maintenance Do-it-yourself service precautions........................................................... 367
Hood.................................................. 369
Positioning a floor jack............... 369
Engine compartment................... 371
12-volt battery................................ 376
Tires ................................................... 380
Tire inflation pressure ................. 387
Wheels.............................................. 389
Air conditioning filter..................390
Windshield wiper inserts........... 392
Electronic key battery ................ 393
Checking and replacing fuses ........................................................... 395
Headlight aim................................. 397
Light bulbs ....................................... 399
7-1. Essential information Emergency flashers...................... 410
If your vehicle has to be stopped in an emergency .............................. 410If the vehicle is trapped in rising
water ................................................. 411
7-2. Steps to take in an emergency If your vehicle needs to be towed............................................................ 413
If you think something is wrong ............................................................ 417
If a warning light turns on or a warn- ing buzzer sounds...................... 418
If a warning messa ge is displayed
.......................................................... 428
If you have a flat tire .................... 432
If the hybrid syst em will not start
.......................................................... 444
If you lose your keys.................... 446
If the fuel filler door cannot be opened .......................................... 446
If the electronic key does not oper- ate properly ................................. 447
If the 12-volt battery is discharged .......................................................... 449
If your vehicle overheats ........... 454
If the vehicle becomes stuck ... 457
8-1. Specifications Maintenance data (fuel, oil level, etc.) ................................................. 460
Fuel information............................ 469
Tire information .............................. 471
8-2. Customization Customizable features .............. 480
8-3. Init

ialization
Items to initialize ........................... 493
6Maintenance and care
7When trouble arises
8Vehicle specifications

13Pictorial index
Precautions for winter season .......................................................................................P.291
To prevent freezing (windshield wiper de-icer)
*.................................................... P.311
Precautions for car wash ............................................................................................... P.357
Fuel filler door ........................................................................................................... P.211
Refueling method ............................................................................................................... .P.211
Fuel type/fuel tank capacity ...... ................................................................................... P.462
Tires.......................................................................................................................... .P.380
Tire size/inflation pressure ............................ ................................................... P.380, 466
Winter tires/tire chains ....................................................................................................P.2 91
Checking/rotation/tire pressure warning system............................................. P.380
Coping with flat tires........................................................................................................ P .432
Hood ..........................................................................................................................P.369
Opening ........................................................................................................................ ....... P.369
Engine oil ..................................................................................................................... ......... P.463
Coping with overheating ............................................................................................... P.454
Warning messages .......................................................................................................... P.428
Headlights/front turn signal lights/front side marker lights ........... P.194, 200
Side turn signal lights ............................................................................................. P.194
Parking lights/daytime running lights............................................................. P.200
Fog lights/cornering lights
*.....................................................................P.200, 206
Rear side marker lights ....................................................................................... P.200
Stop/tail lights ........................................................................................................ P.200
Back-up lights/rear turn signal lights ..................................................... P.194, 200
Shifting the shift lever to R ................................................................................................ P. 191
License plate lights ............................................................................................... P.200
*:If equipped
Light bulbs of the exterior lights for driving
(Replacing method: P.399, Watts: P.468)
E
F
G
H
I
J
K
L
M
N
O

792-1. Instrument cluster
2
Vehicle status information and indicators
Warning lights inform the driver of mal-
functions in the indicated vehicle’s sys-
tems.
Warning lights
(U.S.A.)
Brake system warning light*1
(  P.418)
(red)
(Canada)
Brake system warning light*1
(  P.418)
(yellow)
Brake system warning light*1
(  P.418)
High coolant temperature
warning light
*2 (  P.418)
Hybrid system overheat warn-
ing light
*2 (  P.419)
Charging system warning
light
*3 (  P.419)
Low engine oil pressure warn-
ing light
*2 (  P.419)
(U.S.A.)
Malfunction indicator lamp*1
(  P.419)
(Canada)
Malfunction indicator lamp*1
(  P.419)
SRS warning light
*1 (  P.420)
(U.S.A.)
ABS warning light*1 ( P.420)
(Canada)
ABS warning light*1 ( P.420)
Brake Override System warn-
ing light/Drive-Start Control
warning light
*2 (  P.420)
(red)
Electric power steering system
warning light
*1 ( P.421)
(yellow)
Electric power steering system
warning light
*1 ( P.421)
Low fuel level warning light
(  P.421)
Driver’s and front passenger’s
seat belt reminder light
(  P.421)
(RX450h)
Rear passengers’ seat
belt reminder light
*4
(  P.422)
(RX450hL)
Rear passengers’ seat
belt reminder
light
*4( P.422)
Tire pressure warning light
*1
(  P.422)
(orange)
LTA indicator ( P.422)
(flashes)
Intuitive parking assist OFF indi-
cator
*1 (if equipped) ( P.423)
(flashes)
RCTA OFF indicator*1 (if
equipped) ( P.423)
(flashes)
PKSB OFF indicator*1 (if
equipped) ( P.423)
(flashes or
illuminates)PCS warning light*1 (  P.424)
Slip indicator
*1 (  P.424)
(flashes)
(U.S.A.)
Parking brake indicator
(  P.424)

872-1. Instrument cluster
2
Vehicle status information and indicators
■Display items
 Odometer
Displays the total distance the vehicle has
been driven.
Trip meter A/trip meter B
Displays the distance the vehicle has been
driven since the meter was last reset. Trip
meters A and B can be used to record and
display different distances independently.
 Distance until next engine oil
change
Displays the distance the vehicle can be
driven until an oil change is necessary.
■Changing the display
Each time the “ODO TRIP” switch is
pressed, the displayed item will be changed. When the trip meter is dis-
played, pressing and holding the switch
will reset the trip meter.
■Pop-up display
Distance until next engine oil change
Displays the distance until the next engine
oil change. This display will be displayed in
the following situations:
 When the power switch is turned to
ON mode.
 When a warning message indicating
that oil maintenance should be per-
formed soon or is required is dis-
played.
The brightness of the instrument panel
lights can be adjusted.
If the brightness is adjusted when the sur-
roundings are bright and the tail lights are
on (day mode bright ness adjustment), the
brightness level of night mode will be
adjusted at the same time.
WARNING
For example, there is a lag between the
driver’s shifting and the new gear number
appearing on the display. This lag could
cause the driver to downshift again,
causing rapid and excessive engine brak-
ing and possibly an accident resulting in
death or injury.
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, imme-
diately stop the vehicle in a safe place,
and check the engine after it has
cooled completely. ( P.454)
Odometer and trip meter dis-
play
Changing the instrument panel
light brightness

1664-1. Before driving
WARNING
●Do not drive the vehicle over or stop
the vehicle near flammable materials.
The exhaust system and exhaust gases
can be extremely hot. These hot parts
may cause a fire if there is any flamma-
ble material nearby.
●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 diffi-
cult 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 vehi-
cle in the normal way:
P.410
●Use engine braking (downshift) to
maintain a safe speed when driving
down a steep hill.
Using the brakes continuously may
cause the brakes to overheat and lose
effectiveness. (
P.191)
●Do not adjust the positions of the
steering wheel, the seat, or the inside
or outside rear view mirrors while driv-
ing.
Doing so may result in a loss of vehicle
control.
●Always check that all passengers’
arms, heads 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 off-road driving. Proceed with all
due caution 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
components to short circuit, damage
the hybrid system or cause other seri-
ous damage to the vehicle.
●Do not drive in excess of the speed
limit. Even if the legal speed limit per-
mits 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 not before driving at such speeds.
■When driving on slippery road sur-
faces
●Sudden braking, acceleration and
steering may cause tire slippage and
reduce your ability to control the vehi-
cle.
●Sudden acceleration, engine braking
due to shifting, or changes in engine
speed could cause the vehicle to skid.
●After driving through a puddle, lightly
depress the brake pedal to make sure
that the brakes are functioning prop-
erly. Wet brake pads may prevent the
brakes from functioning properly. If the
brakes on only one side are wet and
not functioning properly, steering con-
trol may be affected.
■When shifting the shift lever
●Do not let the vehicle roll backward
while a forward driving position is
selected, or roll forw ard while the shift
lever is in R.
Doing so may result in an accident or
damage to the vehicle.
●Do not shift the shif t lever to P while
the vehicle is moving.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.
●Do not shift the shift lever to R while
the vehicle is moving forward.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.

1674-1. Before driving
4
Driving
WARNING
●Do not shift the shift lever to a driving
position while the vehicle is moving
backward.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.
●Shifting the shift lever to N while the
vehicle is moving will disengage the
hybrid system. Engine braking is not
available when N is selected.
●Be careful not to shift the shift lever
with the accelerator pedal depressed.
Shifting the shift lever to any position
other than P or N may lead to unex-
pected rapid acceleration of the vehi-
cle that may cause an accident and
result in death or serious injury.
■If you hear a squealing or scraping
noise (brake pad wear limit indica-
tors)
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 acceler-
ate suddenly and unexpectedly, caus-
ing an accident.
●In order to prevent accidents due to
the vehicle rolling away, always keep
depressing the brake pedal while
stopped with the “READY” 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 back-
ward, always depress the brake pedal
and securely apply the parking brake
as needed.
●Avoid revving or racing 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,
spray 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 cause the plastic lenses and plas-
tic material 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 circuit in the vehicle’s electrical
components.
●Do not leave cigarette lighters in the
vehicle. If a cigare tte 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
windshield or windows. Do not place
containers such as air fresheners on
the instrument panel or dashboard.
Adhesive discs or containers may act
as lenses, causing a fire in the vehicle.
●Do not leave a door or window open if
the curved glass is coated with a met-
allized film such as a silver-colored
one. Reflected sunlight may cause the
glass to act as a lens, causing a fire.

1824-1. Before driving
frequently. This could cause the
brakes to overheat and result in
reduced braking efficiency.
 Due to the added load of the trailer,
your vehicle’s engine may overheat
on hot days (at temperatures over
85°F [30°C]) when driving up a
long or steep grade. If the engine
coolant temperature gauge indi-
cates overheating, immediately turn
off the air conditioning (if in use),
pull your vehicle off the road and
stop in a safe spot. ( P.454)
 Always place wheel blocks under
both the vehicle’s and the trailer’s
wheels when parking. Put the trans-
mission in P and apply the parking
brake. Avoid parking on a slope, but
if unavoidable, do so only after per-
forming the following:
1 Apply the brakes and keep them
applied.
2 Have someone place wheel blocks
under both the vehicle’s and trailer’s
wheels.
3 When the wheel blocks are in
place, release the brakes slowly
until the blocks absorb the load.
4 Shift into P and apply the parking
brake.
5 Turn off the hybrid system.
 When restarting after parking on a
slope:
1 With the transmission in P, start the
hybrid system. Be sure to keep the
brake pedal depressed. 2
Shift into a forward gear. If revers-
ing, shift into R.
3 If the parking brake is in manual
mode, release the parking brake.
(P.195)
4 Release the brake pedal, and slowly
pull or back away from the wheel
blocks. Stop and apply the brakes.
5 Have someone retrieve the blocks.

4197-2. Steps to take in an emergency
7
When trouble arises
■Hybrid system overheat warning light*(warning buzzer)
*: This light illuminates on the multi-information display.
■Charging system warning light*
*: Except F SPORT models: This light illuminates on the multi-information display.
F SPORT models: This light illuminates on the meter.
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates the hybrid system has overheated
Stop the vehicle in a safe place.
Handling method ( P.456)
Warning lightDetails/Actions
Indicates a malfunction in the vehicle’s charging system
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer. Continuing to drive the vehicle may be dangerous.
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer.
Warning lightDetails/Actions
(U.S.A.)
or
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engine control system; or
 The electronic throttle control system;
 Have the vehicle inspected by your Lexus dealer immediately.

4307-2. Steps to take in an emergency
not be charged when the shift lever is in N,
shift the shift lever to P when the vehicle is
stopped.
■If “Traction Battery Needs to be Pro-
tected. Shift into P to Restart.” is dis-
played
This message is displayed when the hybrid
battery (traction battery) charge has
become extremely low because the shift
lever has been left in N for a certain amount
of time.
When operating the vehicle, shift to P and
restart the hybrid system.
■If “Shift Is in N Release Accelerator
Before Shifting” is displayed
Message is displayed when the accelerator
pedal has been depressed and the shift
lever is in N.
Release the accelerator pedal and shift the
shift lever to D or R.
■If “Depress Brake when Vehicle Is
Stopped Hybrid Syst em May Overheat”
is displayed
Message is displayed when the accelerator
pedal is depressed to maintain the vehicle
position when stopped on a upward slope,
etc.
If this continues, th e hybrid system may
overheat.
Release the accelerator pedal and depress
the brake pedal.
■If “Power Turned Off to Save Battery” is
displayed
This message is displayed when the power
was cut off due to the automatic power off
function. The next time the hybrid system is
started, increase the engine speed slightly
and maintain it at that speed for approxi-
mately 5 minutes to recharge the 12-volt
battery.
■If “Headlight System Malfunction Visit
Your Dealer” is displayed
The following systems may be malfunction-
ing. Have the vehicle inspected by your
Lexus dealer immediately.
●The LED headlight system
●AFS (Adaptive Front-lighting System) (if equipped)
●The automatic headlight leveling system
●Automatic High Beam
■If “Radar Cruise Control Unavailable
See Owner's Manual” is displayed
The dynamic radar cruise control with
full-speed range system is suspended tem-
porarily or until the problem shown in the
message is re solved. (causes and coping
methods: P.218)
■If “Radar Cruise Control Unavailable” is
displayed
The dynamic radar cruise control with
full-speed range system cannot be used
temporarily. Use the system when it
becomes available again.
■If a message that indicates the malfunc-
tion of front camera is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.218, 424)
●PCS (Pre-Collision system)
●LTA (Lane Tracing Assist)
●Automatic High Beam
●RSA (Road Sign Assist) (if equipped)
●Dynamic radar cruise control with
full-speed range
■If “Maintenance Required Soon” is dis-
played (U.S.A. only)
Indicates that all maintenance according to
the driven distance on the maintenance
schedule
* should be performed soon.
Comes on approximately 4500 miles
(7200 km) after the message has been
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. ( P.362)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed (U.S.A. only)
Indicates that all mainte nance is required to
correspond to the driven distance on the

4547-2. Steps to take in an emergency
“Engine Coolant Temp High Stop in
a Safe Place See Owner’s Manual”
is shown on the multi-information
display
1 Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the hybrid system.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the hybrid system has cooled
down sufficiently, inspect the hoses
WARNING
●Make sure to replace the 12-volt bat-
tery with one designed for this vehicle.
Otherwise, hydrogen gas may enter
the vehicle, possibly causing a fire or
explosion.
●After replacing, securely attach the
exhaust hose and exhaust hole plug to
the exhaust hole of the replaced
12-volt battery. If not properly installed,
gases (hydrogen) may leak into the
vehicle interior, and there is the possi-
ble danger of the gas igniting and
exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another ve hicle in an emer-
gency. It cannot be used to jump start
another vehicle.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The needle of the engine coolant
temperature gauge ( P.83)
enters the red zone, or a loss of
hybrid system power is experi-
enced. (For example, the vehicle
speed does not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” or “Hybrid System
Overheated Output power
reduced” is shown on the
multi-information display.
 Steam comes out from under the
hood.
Correction procedures