2021 LEXUS RX450h engine overheat

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

4567-2. Steps to take in an emergency
Lexus dealer.
If “Hybrid System Overheated Out-
put power reduced” is shown on the
multi-information display
1 Stop the vehicle in a safe place.
2 Stop the hybrid system and care-
fully lift the hood.
3 After the hybrid system has cooled
down, inspect the hoses and radia-
tor core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line 5
Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
6Start the hybrid system and check if
“Hybrid System Overheated Out-
put power reduced” is shown on
the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact
your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the
nearest Lexus dealer.
A
B
A
B
C
WARNING
■When inspecting under the hood of
your vehicle
Observe the following precautions.
Failure to do so may result in serious
injury such as burns.
●If steam is seen coming from under the
hood, do not open the hood until the
steam has subsided. The engine com-
partment may be very hot.

514Alphabetical Index
BrakeBrake hold...................................................... 198
Fluid ......................................................375, 465
Parking brake ............................................... 195
Regenerative braking ................................. 67
Warning light ................................................ 418
Brake assist .................................................... 283
Break-in tips.....................................................165
Brightness control Instrument panel light control ................ 87
BSM (Blind Spot Monitor)........................247
Buzzer Hands off steering wheel warning (LTA)......................................................................... 234
C
Care Exterior ...........................................................356
Interior .............................................................359
Seat belts........................................................359
Wheels and wheel ornaments............356
Cargo capacity..................................... 169, 172
Cargo hooks ................................................. 329
Cargo net hooks .......................................... 329
Center Display .............................................300
Chains .............................................................. 292
Child restraint system Fixed with a LATCH system .................. 54
Fixed with a seat belt...................................50
Front passenger occupant classification system ............................................................. 39
Points to remember .................................... 45
Riding with children ..................................... 45
Types of child restraint system installation method ........................................................... 46
Using an anchor bracket .......................... 57
Child safety 12-volt battery precautions .......378, 453
Airbag precautions...................................... 36
Child restraint system................................. 46
Heated steering wheel and seat heater precautions................................................. 318 How your child should wear the seat belt
............................................................................. 27
Moon roof precautions.............................157
Panoramic moon roof precautions ... 160
Power back door precautions ............... 113
Power window lock switch .................... 155
Power window precautions .................. 154
Rear door child-protectors ..................... 112
Seat belt extender precautions.............. 27
Seat belt precautions .................................. 45
Child-protectors............................................. 112
Cleaning Exterior........................................................... 356
Interior ............................................................ 359
Radar sensor ..................................................214
Seat belts ....................................................... 359
Wheels and wheel ornaments ........... 356
Clock ........................................................83, 343
Coat hooks..................................................... 343
Coin box.......................................................... 328
Compass ......................................................... 352
Condenser ..................................................... 374
Console box .................................................. 326
Cooling system............................................. 373 Engine overheating...................................454
Hybrid system overheating ................. 456
Cornering lights ........................................... 202 Replacing light bulbs ............................... 400
Cruise control Dynamic radar cruise control with full-speed range ......................................238
Cup holders ................................................... 327
Current fuel consumption .......................... 90
Curtain shield airbags .................................. 30
Customizable features ..............................480
D
Daytime running light system .................200
Defogger Outside rear view mirrors.................... 306
Rear window ............................................... 306
Windshield ................................................... 306

516Alphabetical Index
If the electronic key does not operate properly....................................................... 447
If the fuel filler door cannot be opened ......................................................................... 446
If the hybrid system will not start ........ 444
If the vehicle is trapped in rising water411
If you have a flat tire .................................. 432
If you lose your keys................................. 446
If you think something is wrong ........... 417
If your vehicle becomes stuck............. 457
If your vehicle has to be stopped in an
emergency ................................................. 410
If your vehicle needs to be towed ....... 413
If your vehicle overheats ........................ 454
Energy monitor ..................................... 99, 100
Engine ACCESSORY mode ...............................187
Compartment ............................................... 371
Engine switch................................................ 184
Hood................................................................369
How to start the hybrid system ........... 184
Identification number .................................461
If the hybrid system will not start ........ 444
If your vehicle has to be stopped in an
emergency ................................................. 410
Ignition switch (power switch) ............. 184
Overheating................................................. 454
Power switch ................................................ 184
Tachometer ..................................................... 83
Engine coolant Capacity ......................................................... 464
Checking ....................................................... 373
Preparing and checking before winter........................................................................... 291
Engine coolant temperature gauge ....... 83
Engine oil Capacity ......................................................... 463
Checking ......................................................... 371
Preparing and checking before winter........................................................................... 291
Warning light .................................................419
Engine oil maintenance data .................. 373 Engine switch (power switch) ................. 184
If your vehicle has to be stopped in an emergency .................................................. 410
EPS (Electric Power Steering) .............. 284 Warning light .................................................421
EV drive mode............................................... 189
EV indicator .......................................................67
Event data recorder (E DR) ........................... 8
F
Flat tire
Tire pressure warning system .............382
Vehicles with a spare tire....................... 432
Floor mats .......................................................... 24
Fluid Brake ............................................................... 465
Hybrid transmission................................. 465
Washer ...........................................................375
Fog lights Switch.............................................................. 206
Footwell light ...................................................321
Front automatic air conditioning system .......................................................................... 304
Front fog lights Replacing light bulbs ............................... 400
Front passenger footwell hooks ............ 345
Front passenger occupant classification system .............................................................. 39
Front seats Adjustment ....................................................... 131
Cleaning ........................................................ 359
Correct driving posture ............................ 25
Driving position memory .........................142
Head restraints............................................. 145
Memory recall function.............................143
Power easy access system .....................142
Seat heaters ................................................... 318
Seat position memory ...............................142
Seat ventilators ............................................. 318
Front side marker light Light switch .................................................. 200
Replacing light bulbs ............................... 400

518Alphabetical Index
High voltage components ....................... 69
Hybrid system precautions ..................... 69
If the hybrid system will not start ........ 444
Overheating.................................................456
Power (ignition) switch............................ 184
Regenerative braking ................................. 67
Starting the hybrid system...................... 184
Hybrid System Indicator......................85, 99
Hybrid transmission....................................... 191 M mode ............................................................193
Paddle shift switches ....................... 192, 193
Hybrid vehicle driving tips ....................... 289
I
I/M test ............................................................ 366
Identification Engine ...............................................................461
Vehicle ............................................................460
If your vehicle has to be stopped in an
emergency ................................................... 410
Ignition switch (power switch) ................ 184 Auto power off function ...........................187
Changing the power switch modes ..187
If your vehicle has to be stopped in an
emergency ................................................. 410
Immobilizer system .........................................73
Indicators ........................................................... 80
Initialization Items to initialize ......................................... 493
Maintenance .................................... 362, 373
Power windows............................................153
Tire pressure warning system ............ 385
Inside rear view mirror ................................149
Instrument panel light control ................... 87
Interior lights....................................................321 Front interior light ........................................ 321
Rear interior light ......................................... 321
Intuitive parking assist.....................253, 255 Function .......................................................... 255
Warning message..................................... 257
J
JackPositioning a floor jack ........................... 369
Vehicle-equipped jack ...........................433
Jack handle .................................................... 433
Jam protection function Electronic sunshade .................................. 159
Moon roof ...................................................... 156
Panoramic moon roof .............................. 159
Power back door.......................................... 119
Power windows ........................................... 153
Rear seats ........................................................132
K
Keyless entrySmart access system with push-button start ................................................................. 125
Wireless remote control ......................... 107
Keys Battery-saving function.............................126
Electronic key ............................................... 106
If the electronic key does not operate properly ....................................................... 447
If you lose your keys .................................446
Key number plate ....................................... 106
Keyless entry ....................................... 107, 125
Mechanical key ............................................ 106
Power switch................................................. 184
Replacing the battery ...............................393
Warning buzzer .......................................... 125
Wireless remote control ......................... 107
Knee airbags .................................................... 30
L
Lane Tracing Assist (LTA) Operation ...................................................... 227
Warning messages...................................235
Language (multi-information display) ... 92
LATCH anchors ............................................. 54

520Alphabetical Index
Dynamic radar cruise control with full-speed range ...................................... 238
Energy monitor............................................ 100
G-force................................................................ 91
LTA (Lane Tracing Assist).................... 232
Menu icons ...................................................... 89
Meter control switches .............................. 89
Navigation system-linked display ........ 92
Pop-up display...............................................88
Settings .............................................................. 92
Suggestion function..................................... 93
Tire pressure ................................................ 382
Units ...................................................................... 91
Warning message..................................... 428
N
Navigation system-linked display....92, 98
Noise from under vehicle ...............................6
O
“ODO TRIP” switch ...................................... 87
Odometer ......................................................... 87
Odometer and trip meter display Display items ................................................... 87
“ODO TRIP” switch .................................... 87
Pop-up display............................................... 87
Oil Engine oil ....................................................... 463
Rear differential oil ....................................465
Opener Fuel filler door..................................................211
Hood................................................................369
Outer foot lights Location............................................................ 321
Outside door handle lights........................321
Outside rear view mirrors Adjustment..................................................... 150
BSM (Blind Sport Monitor) ................. 247
Folding ............................................................... 151
Linked mirror functi on when reversing
.......................................................................... 150 Mirror position memory ...........................142
Outside rear view mirror defoggers306
RCTA function ..............................................261
Outside temperature.................................... 83
Overheating .................................................. 454
P
Paddle shift switches ..........................192, 193
Panic mode ......................................................107
Panoramic moon roof Jam protection function ........................... 159
Operation ....................................................... 158
Parking assist sensors (intuitive parking assist) ............................................................. 255
Parking brake Operation ....................................................... 195
Parking brake engaged warning buzzer............................................................................197
Warning light ............................................... 424
Warning message .......................................197
Parking lights Light switch .................................................. 200
Replacing light bulbs ............................... 400
Parking Support Brake function (for rear-crossing vehicles) ...........................277Function .......................................................... 277
Parking Support Brake function (static objects) ........................................................... 271Function ............................................................ 271
PCS (Pre-Collision System) Function ..........................................................220
PCS OFF switch ........................................ 222
Warning light ............................................... 424
Personal lights.................................................321
PKSA (Parking Support Alert) .............. 253
PKSB (Parking Support Brake)............. 266 Warning message ..................................... 270
Power back door ............................................ 113 Hands Free Power Back Door ............. 116
Smart access system with push-button start ................................................................... 114
Power control unit.......................................... 69

525Alphabetical Index
Intuitive parking assist.................. 260, 423
Low engine oil pressure...........................419
LTA (Lane Tracing Assist)227, 230, 422
Open door........................................................112
Open window ...............................................154
PKSA (Parking Support Alert) ........... 253
PKSB (Parking Support Brake) ......... 423
Pre-collision braking.................................. 221
RCTA (Rear Cross Traffic Alert) ...... 423
Seat belt ................................................ 421, 422
Warning label .................................................. 69
Warning lights................................................ 418 ABS .................................................................. 420
Brake hold operated indicator ........... 425
Brake Override System ......................... 420
Brake system ................................................ 418
Charging system .........................................419
Drive-Start Control .................................. 420
Electric power steering ............................ 421
High coolant temperature ..................... 418
Hybrid system overheat warning light...........................................................................419
Intuitive parking assist OFF indicator423
Low engine oil pressure...........................419
Low fuel level ................................................. 421
LTA indicator ............................................... 422
Malfunction indicator lamp.....................419
Master warning light ................................ 425
Parking brake indicator .......................... 424
PKSB OFF indicator ................................ 423
Pre-collision system ................................. 424
RCTA OFF indicator............................... 423
Seat belt reminder light ................ 421, 422
Slip indicator ................................................ 424
SRS.................................................................... 420
Tire pressure ................................................ 422
Warning messages ..................................... 428
Washer Adding ............................................................ 375
Preparing and checking before winter........................................................................... 291
Switch ..............................................................206 Washing and waxing.................................. 356
Weight
Cargo capacity .................................. 169, 172
Load limits ....................................................... 172
Weight............................................................ 460
Wheels ............................................................. 389 Size ....................................................................466
Window lock switch .................................... 155
Windows Power windows ........................................... 153
Rear window defogger.......................... 306
Washer .......................................................... 206
Windshield wiper de-icer ........................... 311
Windshield wiper inserts .......................... 392
Windshield wipers Position........................................................... 208
Rain-sensing windshield wipers ........ 206
Replacing a windshield wiper insert.392
Winter driving tips.........................................291
Wireless charger ......................................... 335
Wireless remote control Battery-Saving Function...........................126
Locking/Unlocking ................................... 107
Replacing the battery ...............................393
For information regarding the equipment listed below, refer to
the “NAVIGATION AND MULTI-
MEDIA SYSTEM OWNER’S
MANUAL”.
· Navigation system
· Audio/visual system
· Panoramic view monitor
· Lexus parking assist monitor