
5597-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
The coolant level is satisfactory if it is between the “FULL”/“F” and “LOW”/
“L” lines on the reservoir.Reservoir
“FULL”/“F”
“LOW”/“L”
Add coolant if necessary.
Water can be used in an emergency if po wer control unit coolant is unavailable.
Start the hybrid system and check for the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
If the message is not displayed:
Have the vehicle inspected at the nearest any authorized Lexus dealer or repairer,
or another duly qualified and equipped professional.
4
1
2
3
XGS450h XGS300h
5
XGS450h XGS300h
6

5607-2. Steps to take in an emergency
GS450h_300h_OM_OM30F00E_(EE)
■When adding coolant
Add coolant in accordance with the following procedure.Remove caps A and B.
Add coolant through the inlet of cap A up to the “[GR-HV] B” line/“[AR/GR] B” line,
and then install cap A.
Add coolant through the inlet of cap B un til it is full, and then install cap B.
GS300h only: When installing cap B, apply coolant to the O-ring on the end of cap B.
Cap A
Cap B
GS450h: “[GR-HV] B” line (Target fill line)
GS300h: “[AR/GR] B” line (Target fill line)
1
2
3
GS300h
GS450h
1
2
3

5617-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
WA R N I N G
■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 compartment may be very hot.
●After the hybrid system has been turned off, check that the indicator on the power
switch and the “READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automatically start, or
the cooling fan may suddenly operate even if the gasoline engine stops. Do not touch
or approach rotating parts such as the fan, which may lead to fingers or clothing
(especially a tie, a scarf or a muffler) ge tting caught, resulting in serious injury.
●Do not loosen the coolant inlet cap or the
coolant reservoir caps while the hybrid sys-
tem and radiator are hot.
High temperature steam or coolant could
spray out. XGS450h
XGS300h

5627-2. Steps to take in an emergency
GS450h_300h_OM_OM30F00E_(EE)
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid system 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 system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use any coolant additive.

5728-1. Specifications
GS450h_300h_OM_OM30F00E_(EE)
Cooling system
Gasoline engine
Power control unit
Left-hand drive vehiclesRight-hand drive vehicles
Capacity
GS450h9.2 L (9.7qt.,
8.1 Imp.qt.)2.1 L (2.2qt.,
1.8 Imp.qt.)1.9 L (2.0qt.,
1.7 Imp.qt.)
GS300h8.1 L (8.6 qt.,
7.1 Imp.qt.)1.6 L (1.7 qt.,
1.4 Imp.qt.)1.8 L (1.9 qt.,
1.6 Imp.qt.)
Coolant typeUse either of the following:• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-sili-cate, non-amine, non-nitrite, and non-borate cool-
ant with long-life hybrid organic acid technology
Do not use plain water alone.
Ignition system
Spark plug
Make
GapDENSO FK20HBR8
0.8 mm (0.031 in.)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.

604Alphabetical index
GS450h_300h_OM_OM30F00E_(EE)
Cargo hooks........................................... 394
CD player
*
Chains .......................................................355
Child restraint system ............................ 56Baby seats, definition .......................... 57
Baby seats, installation ....................... 66
Child seats, definition.......................... 57
Child seats, installation....................... 66
Installing CRS with ISOFIX rigid anchors........................................ 69
Installing CRS with seat belts.......... 66
Installing CRS with top strap .......... 70
Junior seats, definition ........................ 57
Junior seats, installation .....................68
Child safety................................................. 55 12-volt battery
precautions........................... 430, 555
Airbag precautions .............................. 45
Child restraint system......................... 56
How your child should
wear the seat belt ..................... 39, 40
Installing child restraints .................... 65
Moon roof precautions ................... 198
Power window lock switch.............193
Power window precautions .......... 195
Rear door child-protectors ............143
Removed electronic key battery precautions ....................... 452
Seat belt comfort guide ..................... 39
Seat belt precautions .......................... 42
Seat heater precautions .................. 381
Trunk precautions ..............................149
Child-protectors ................................... 143 Cleaning.........................................406, 410
Aluminum wheels.............................. 407
Exterior ................................................... 406
Interior.......................................................410
Seat belts ................................................... 411
Clock ...............................................105, 398
Coat hooks.............................................. 402
Condenser ..............................................427
Console box ........................................... 390
Console box light ...................................391
Coolant..................................................... 425 Capacity..................................................572
Checking ............................................... 425
Preparing and checking
before winter.................................... 354
Cooling system ..................................... 425
Engine overheating .......................... 556
Hybrid system overheating.......... 556
Consumption screen ........................... 126
Cruise control Cruise control ......................................327
Dynamic radar cruise control ....... 315
Dynamic radar cruise control with full-speed range ................... 303
Cup holders ..............................................391
Curtain shield airbags .......................... 43
Customizable features........................ 581

606Alphabetical index
GS450h_300h_OM_OM30F00E_(EE)
Dynamic radar cruise control with full-speed range .......................303
Function ..................................................303
Warning message.............................482
Dynamic Rear Steering (DRS)........345 Function ..................................................345
Warning message.............................482
DVD player
*
Eco drive mode .....................................330
Electric motor (traction motor) ......... 75
Electric Power Steering (EPS)........345 Function ..................................................345
Warning light ....................................... 477
Warning message.............................482
Electronic key.......................................... 134 Battery-saving function.................... 155
If the electronic key does not operate properly ........................... 548
Replacing the battery.........................451
Emergency, in case of
If a warning buzzer sounds .......... 476
If a warning light turns on............... 476
If a warning message is displayed ............................................ 482
If the 12-volt battery is discharged.......................................... 551
If the electronic key does not operate properly ........................... 548
If the hybrid system will not start ........................................................543
If the parking brake cannot be released........................................546 If the shift lever cannot be
shifted from P................................... 545
If you have a flat tire................517, 528
If you think something is wrong .............................................. 475
If your vehicle becomes stuck .... 563
If your vehicle has to be stopped in an emergency ......... 469
If your vehicle needs to be towed ............................................ 470
If your vehicle overheats................ 556
Emergency brake signal.................... 345
Emergency flashers............................. 468
Emergency tire puncture
repair kit ................................................ 528
Energy monitor ....................................... 126
Engine ....................................................... 568 Accessory mode ................................. 218
Compartment ....................................... 419
Engine switch ........................................ 217
Hood ......................................................... 417
How to start the hybrid
system.................................................... 217
Identification number.......................568
Ignition switch (power switch) .................................. 217
Overheating ........................................ 556
Power switch ......................................... 217
Engine compartment cover ...............421
Engine coolant....................................... 425 Capacity..................................................572
Checking ............................................... 425
Preparing and checking before winter.................................... 354
E

607Alphabetical index
GS450h_300h_OM_OM30F00E_(EE)
Engine coolant temperature gauge....................................................... 105
Engine oil.................................................. 422 Capacity .................................................570
Checking ............................................... 422
Oil level warning message ........... 482
Oil pressure warning message..............................................482
Preparing and checking before winter ....................................354
Engine switch ...........................................217 Auto power off function ...................219
Changing the power switch modes ................................................... 218
If your vehicle has to be stopped in an emergency..........469
Starting the hybrid system............... 217
EPS (Electric Power Steering)........345
Function ..................................................345
Warning light ....................................... 477
Warning message.............................482
EV drive mode ....................................... 222
First-aid kit storage net.......................395
Flat tire
Vehicles with spare tire ....................517
Vehicles without spare tire ...........528
Floor mats ................................................... 34
Fluid Brake........................................................ 574
Hybrid transmission ......................... 573
Washer ................................................... 427 Fog lights .................................................. 249
Replacing light bulbs ....................... 465
Switch ...................................................... 249
Follow me home system .................... 237
Footwell light .......................................... 386
Front air conditioning system .......... 366
Front fog lights ....................................... 249 Replacing light bulbs ....................... 465
Switch ...................................................... 249
Wattage ................................................. 465
Front personal lights............................ 387
Front position lights ............................. 236 Light switch........................................... 236
Replacing light bulbs ....................... 465
Welcome light illumination control ...................................................140
Front seats ................................................. 175 Adjustment ............................................. 175
Cleaning .................................................. 410
Correct driving posture.................... 36
Driving position memory ................ 178
Head restraints .....................................183
Power easy access system............. 178
Seat heaters.......................................... 382
Seat position memory ....................... 178
Seat ventilators ................................... 382
Front turn signal lights ........................ 230 Replacing light bulbs ...........459, 465
Turn signal lever................................. 230
Wattage ................................................. 578
F
*: Refer to the “NAVIGATION AND MULTIMEDIA SYSTEM OWNER’S MANUAL”.