2021 LEXUS RX450h coolant temperature

4177-2. Steps to take in an emergency
7
When trouble arises
Fluid leaks under the vehicle
(Water dripping from the air condi-
tioning after use is normal.)
 Flat-looking tires or uneven tire
wear
 Engine coolant temperature gauge
needle continually points higher
than normal
 Changes in exhaust sound
 Excessive tire squeal when corner-
ing
 Strange noises related to the sus-
pension system
 Pinging or other noises related to
the hybrid system
 Engine missing, stumbling or run-
ning roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking 
Vehicle pulls heavily to one side
when driving on a level road
 Loss of brake effectiveness, spongy
feeling, pedal almost touches the
floor
If you think something is
wrong
If you notice any of the following
symptoms, your vehicle probably
needs adjustment or repair. Con-
tact your Lexus dealer as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms

4187-2. Steps to take in an emergency
■Brake system warning light
■Brake system warning light
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
If a warning light turns on or a warning buzzer sounds
Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, bu t then goes off, this does not necessar-
ily indicate a malfunction in the system. However, if this continues to occur,
have the vehicle inspected by your Lexus dealer.
Actions to the warning lights or warning buzzers
Warning lightDetails/Actions
(U.S.A.)
or
(red)
(Canada)
Indicates that:
 The brake fluid level is low; or
 The brake system is malfunctioning
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer. Continuing to drive the vehicle may be dangerous.
Warning lightDetails/Actions
(yellow)
Indicates a malfunction in:
 The regenerative braking system;
 The electronically controlled brake system; or
 The electric parking brake
 Have the vehicle inspected by your Lexus dealer immediately.
Warning lightDetails/Actions
Indicates that the engine coolant temperature is too high
Immediately stop the vehicle in a safe place.
Handling method ( P.454)

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

4577-2. Steps to take in an emergency
7
When trouble arises
1Stop the hybrid system. Shift the
shift lever to P and set the parking
brake.
2 Remove the mud, snow or sand
from around the front wheels.
3 Place wood, stones or some other
material under the front wheels to
help provide traction.
4 Restart the hybrid system.
5 Shift the shift lever to D or R and
release the parking brake. Then,
while exercising caution, depress
the accelerator pedal.
■When it is difficult to free the vehicle
Press to turn off TRAC.
WARNING
●After the hybrid system has been
turned off, check that the “READY”
indicator is off.
When the hybrid system is operating,
the gasoline engine may automatically
start, or the cooling fans may suddenly
operate even if the gasoline engine
stops. Do not touch or approach rotat-
ing parts such as the fans, which may
lead to fingers or cl othing (especially a
tie, a scarf or a muffler) getting caught,
resulting in serious injury.
●Do not loosen the radiator cap and the
coolant reservoir caps while the hybrid
system and radiator are hot.
High temperature steam or coolant
could spray out.
NOTICE
■When adding engine/power control
unit coolant
Add coolant slowly after the hybrid sys-
tem has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too
quickly can cause damage to the hybrid
system.
■To prevent damage to the cooling sys-
tem
Observe the following precautions:
●Avoid contaminating the coolant with
foreign matter (such as sand or dust,
etc.).
●Do not use any coolant additive.
If the vehicle becomes stuck
Carry out the following proce-
dures if the tires spin or the vehicle
becomes stuck in mud, dirt or snow:
Recovering procedure

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

524Alphabetical Index
Tire pressure warning systemFunction .......................................................... 382
Initializing ...................................................... 385
Installing tire pressure warning valves and transmitters ......................................384
Registering ID codes ............................... 387
Warning light ............................................... 422
Tires Chains ............................................................. 292
Checking ...................................................... 380
If you have a flat tire .................................. 432
Inflation pressure........................................ 387
Information ...................................................... 471
Replacing ....................................................... 432
Rotating tires ................................................ 382
Size.................................................................... 466
Snow tires ........................................................ 291
Spare tire........................................................ 432
Tire inflation pressu re display function
......................................................................... 382
Tire pressure warning system ............. 382
Warning light ............................................... 422
Tools.................................................................. 433
Top tether strap................................................57
Total load capacity ...................................... 460
Towing Dinghy towing .............................................. 183
Emergency towing ..................................... 413
Towing eyelet ................................................415
Trailer towing ................................................. 173
TRAC (Traction Control) ........................ 284
Traction battery (hybrid battery) Hybrid battery (traction battery) air vents.............................................................................. 71
Location............................................................. 69
Specification ................................................. 462
Warning message.........................................72
Traction Control (TRAC) ........................ 284
Traction motor (electric motor) ............... 66
Trailer Sway Control.................................. 284
Trailer towing .................................................. 173 Transmission
Driving mode select switch ................... 281
Hybrid transmission..................................... 191
M mode ........................................................... 193
Paddle shift switches ....................... 192, 193
Trip meters ........................................................ 87
Turn signal lights Replacing light bulbs ............................... 400
Turn signal lever .......................................... 194
Wattage ......................................................... 468
U
USB charging ports.................................... 334
V
Vanity lights.................................................... 345Wattage ......................................................... 468
Vanity mirrors ............................................... 345
VDIM (Vehicle Dynamics Integrated Man- agement)...................................................... 284
Vehicle data recording ....................................7
Vehicle Dynamics Integrated Manage- ment (VDIM).............................................. 284
Vehicle identification number ................ 460
Vehicle Stability Control (VSC) ........... 283
Ventilators (seat ventilators).................... 318
VSC (Vehicle Stability Control) ........... 283
W
Warning buzzers Approach warning.................................... 244
Brake Override System .........................420
Door lock .......................................................... 110
Downshifting ................................................. 193
Drive-Start Control...................................420
Electric power steering.............................421
Hands off steering wheel warning (LTA).......................................................................... 234
High coolant temperature...................... 418
Hybrid system overheat .......................... 419

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