2018 LEXUS LS500H overheating

4537-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 7
When trouble arises 
If the engine coolant temperature
gauge enters the red zone or
“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 and radiator core (radiator) for any
leaks.
Radiators
Cooling fan If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4 The coolant level is satisfactory if it
is between the “F” and “L” lines on
the reservoir.
Reservoir
“F” line
“L” line
Coolant inlet cap
5 Add coolant if necessary.
( → P.455) Water can be used in an emergency if If your vehicle overheats The following may indicate that
your vehicle is overheating.
 The engine coolant temperature
gauge ( → P.77, 81) is in the red
zone or a loss of hybrid system
power is experienced. (For exam-
ple, the vehicle speed does not
increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” or “Hybrid System
Overheated Reduced Output
Power” is shown on the
multi-information display.
 Steam comes out from under the
hood.
Correction procedures A
B
A
B
C
D

512 Alphabetical Index
LS500h_OM_OM50F42U_(U) C
Card key .......................................................... 104
Care
Aluminum wheels ...................................... 370
Exterior ........................................................... 370
Interior ............................................................. 373
Seat belts........................................................ 373
Cargo capacity...............................................166
Cargo net ....................................................... 348
Center Display ...............................................316
Chains ............................................................... 310
Child restraint system
Fixed with a LATCH system .................. 53
Fixed with a seat belt................................... 49
Front passenger occupa nt classification
system ............................................................. 40
Points to remember .................................... 45
Riding with children ..................................... 45
Types of child restraint system installation
method ........................................................... 46
Using an anchor bracket .......................... 55
Child safety
12-volt battery precautions ........ 394, 451
Airbag precautions...................................... 34
Child restraint system................................. 46
Heated steering wheel and seat heater
precautions................................................ 337
How your child should wear the seat belt
............................................................................ 25
Moon roof precautions ............................154
Power window lock switch.....................153
Power window precautions ...................152
Rear door child-protectors ....................... 111
Removed electronic key battery precau-
tions ................................................................. 414
Seat belt extender precautions ............. 25
Seat belt precautions .................................. 45
Trunk precautions .........................................112
Child-protectors...............................................111
Cleaning
Aluminum wheels ...................................... 370 Exterior............................................................370
Interior ............................................................. 373
Radar sensor ........................ 199, 200, 206
Seat belts ........................................................ 373
Clock ................................................. 77, 81, 353
Clock light ...................................................... 340
Coat hooks..................................................... 352
Coin holder .................................................... 345
Condenser .......................................................391
Console box .................................................. 346
Cooling system............................................. 390
Engine overheating...................................453
Hybrid system overheating ..................454
Cornering lights .............................................187
Cruise control
Dynamic radar cruise control with
full-speed range ..........................247, 250
Cup holders ................................................... 345
Current fuel consumption .......................... 88
Curtain shield airbags .................................. 29
Customizable features ............................... 481
D
Daytime running light system .................. 185
Defogger
Outside rear view mirrors..................... 324
Rear window ................................................ 324
Windshield .................................................... 324
Differential
Front differential oi l............. ...................... 465
Rear differential oil......... .......... ........... ...... 465
Dimension ...................................................... 460
Dinghy towing................................................. 167
Display
Center Display ............................................. 316
Dynamic radar cruise control with
full-speed range ..................................... 250
Energy monitor .............................................. 96
Head-up display............................................ 92
Intuitive parking assist ..............................266
LKA (Lane-Keeping Assist) ................. 243
LTA (Lane-Tracing Assist) ................... 234

514 Alphabetical Index
LS500h_OM_OM50F42U_(U) emergency ................................................ 420
If your vehicle needs to be towed ..... 422
If your vehicle overheats ........................ 453
Energy monitor ....................................... 96, 97
Engine
ACCESSORY mode ...............................170
Compartment ............................................. 387
Engine compartment cover ................ 388
Engine switch................................................ 168
Hood............................................................... 385
How to start the hybrid system ........... 168
Identification number .................................461
If the hybrid system will not start ........ 443
If your vehicle has to be stopped in an
emergency ................................................ 420
Ignition switch (power switch) ............. 168
Overheating................................................. 453
Power switch ................................................ 168
Tachometer .............................................. 77, 81
Engine compartment cover ....................388
Engine coolant
Capacity ......................................................... 463
Checking .......................................................390
Preparing and checking before winter
.........................................................................309
Engine coolant temperature gauge .77, 81
Engine oil
Capacity ......................................................... 462
Checking ...................................................... 388
Preparing and checking before winter
.........................................................................309
Warning light ............................................... 428
Engine oil maintenance data .................. 390
Engine switch (power switch) ................. 168
If your vehicle has to be stopped in an
emergency ................................................ 420
EPS (Electric Power Steering) .............. 303
Warning light ...............................................430
EV drive mode................................................ 172
EV indicator ...................................................... 59
Event data recorder (EDR) ............................7 F
FCTA (Front Cross Traffic Alert) ..........227
First-aid kit storage belt ............................ 349
Flat tire
Tire pressure warning system ............. 397
Floor mats ...........................................................22
Fluid
Brake ............................................................... 465
Hybrid transmission..................................464
Washer ............................................................ 391
Footwell light ................................................. 340
Front air conditioning system ................. 323
Front Cross Traffic Alert (FCTA) ..........227
Front passenger occupant classification
system .............................................................. 40
Front seats
Adjustment ..................................................... 128
Cleaning ......................................................... 373
Correct driving posture ............................ 23
Driving position memory ........................ 139
Head restraints..............................................144
Memory recall function.............................142
Power easy access system .................... 139
Refresh system ............................................. 133
Seat heaters ..................................................336
Seat position memory .............................. 139
Seat ventilators ............................................336
Front side marker light
Light switch .................................................... 185
Replacing light bulbs ..................................417
Front turn signal lights
Replacing light bulbs ..................................417
Turn signal lever .......................................... 180
Fuel
Capacity .......................................................... 461
Fuel gauge ................................................. 77, 81
Information ....................................................470
Refueling.......................................................... 194
Type ................................................................... 461
Warning light .............................................. 430

5151-1. What to do if... (Troubleshooting)
LS500h_OM_OM50F42U_(U) 515Alphabetical Index
Fuel consumption
Average fuel economy ..............................88
Current fuel consumption........................88
Fuel filler door
If the fuel filler door cannot be opened
......................................................................... 445
Refueling ..........................................................194
Fuel gauge ...................................................77, 81
Fuses ...................................................................414 G
Garage door opener .................................358
Gauges .........................................................77, 81
Gear Position................................................... 89
G-force............................................................... 89
Glove box ....................................................... 344
Glove box light ............................................. 345
H
Hands Free Power Trunk Lid .................... 115
Head restraints ...............................................144
Headlights
Adaptive Front-lighting System (AFS)
...........................................................................187
Automatic High Beam system............. 188
Light switch .................................................... 185
Replacing light bulbs.................................. 417
Head-up display.............................................. 92
Driving information display area........... 92
Driving support system display area .. 95
HUD (Head-up display) switch............ 94
Hybrid System Indicator ........................... 96
Navigation system-linked display ........ 92
Pop-up display............................................... 95
Settings .............................................................. 94
Heated steering wheel .............................. 336
Heaters
Front air conditioning system .............. 323
Heated steering wheel............................ 336
Outside rear view mirrors .................... 324
Rear air conditioning system ............... 333 Seat heaters ..................................................336
Height control
Electronically modulated air suspension
......................................................................... 300
High-voltage components ........................... 61
Hill-start assist control ............................... 303
Hood
Open............................................................... 385
Pop Up Hood.................................................38
Hooks
Coat hooks ...................................................352
Retaining hooks (floor mat) ..................... 22
Horn .................................................................... 147
HUD (Head-up display) switch ................ 94
Hybrid battery (traction battery)
Location ...............................................................61
Specification ................................................. 462
Warning message ........................................ 64
Hybrid battery (traction battery) air vents
............................................................................. 64
Hybrid system .................................................. 58
Emergency shut off system...................... 64
Energy monitor/consumption screen96
EV drive mode.............................................. 172
High voltage components .........................61
Hybrid system precautions........................61
If the hybrid system will not start ........ 443
Overheating .................................................454
Power (ignition) switch ............................ 168
Regenerative braking .................................59
Starting the hybrid system ...................... 168
Vehicle proximity noti fication system.60
Hybrid System Indicator............. 78, 83, 96
Hybrid transmission...................................... 174
M mode ............................................................179
Paddle shift switches ....................... 178, 179
Snow mode..................................................... 177
Hybrid vehicle driving tips ....................... 307
I
I/M test ............................................................ 382

518 Alphabetical Index
LS500h_OM_OM50F42U_(U) Meter control switches .............................. 87
Navigation system-linked display ........ 89
Pop-up display............................................... 86
Settings .............................................................. 90
Suggestion function....................................... 91
Tire pressure ................................................ 397
Units .................................................................... 89
Vehicle sway warning ................................ 89
Warning message..................................... 437 N
Navigation system-linked display....89, 92
Noise from under vehicle ...............................6 O
“ODO TRIP”switch ............................... 79, 85
Odometer ................................................. 79, 84
Odometer and trip meter display
Display items .......................................... 79, 84
“ODO TRIP” switch ........................... 79, 85
Pop-up display...................................... 79, 85
Oil
Engine oil ....................................................... 462
Front differential oil ...................................465
Rear differential oil ....................................465
Opener
Fuel filler door................................................194
Hood............................................................... 385
Trunk ....................................................................114
Outer foot lights
Location..........................................................340
Outside door handle lights...................... 340
Outside rear view mirrors
Adjustment......................................................149
BSM (Blind Sport Monitor) .................260
Folding ............................................................. 150
Linked mirror functi on when reversing
...........................................................................149
Mirror position memory...........................139
Outside rear view mirror defoggers324
RCTA function ............................................ 273 Outside temperature..............................77, 81
Overheating .................................................. 453 P
Paddle shift switches .......................... 178, 179
Panic mode ..................................................... 106
Parking assist sensors (intuitive parking
assist) ............................................................. 266
Parking brake
Operation ......................................................... 181
Parking brake engaged warning buzzer
........................................................................... 182
Warning light ...............................................434
Warning message ...................................... 182
Parking lights
Light switch .................................................... 185
Replacing light bulbs ..................................417
Parking Support Brake function (for
rear-crossing vehicles) ............................291
Function ............................................................291
Parking Support Brake function (rear
pedestrians) .................................... 280, 295
Function ..........................................................295
Parking Support Brake function
(rear-crossing vehicles).........................280
Parking Support Brake function (static
objects) ............................................. 280, 286
Function ......................................................... 286
PCS (Pre-Collision System)
Function ............................................. 209, 220
PCS OFF switch .............................. 212, 222
Warning light ...............................................433
Warning message ...........................219, 226
Personal lights............................................... 340
PKSA (Parking Support Alert) .............. 265
PKSB (Parking Support Brake).............280
Warning message .....................................284
Pop Up Hood................................................... 38
Power control unit............................................ 61
Power control unit coolant
Capacity .........................................................463
Checking ...................................................... 390