2007 Lexus GS450h overheating

11
1-1. Hybrid system
1
Before driving
NOTICE
■Hybrid battery air vent
●Do not put foreign objects over the air vent. The hybrid battery (traction battery)
may overheat and be damaged.
●Clean the air vent regularly to prevent the hybrid battery (traction battery) from
overheating.
●Do not wet the air vent. It may cause a short circuit and damage the hybrid bat-
tery (traction battery).
●Do not load a large amount of water such as an aquarium into the vehicle. If water
spills over the hybrid battery (tractio n battery), the battery may be damaged.

113
2-2. Instrument cluster
2
When driving
NOTICE
■To prevent damage to the engine and its components
The engine may be overheating if the engine coolant temperature gauge is in the
red zone (“H”). In this case, immediately stop the vehicle in a safe place. Check the
engine after it has cooled completely. (P. 475)
■To activate the light sensitivity function properly
Do not affix a sticker or window tint to the rear window glass, or put an object
behind the rear seat.

165
2-4. Using other driving systems
2
When driving
■VGRS is disabled in the following situations
●During stopping or the steering wheel has been moved for a long time while
driving at lower speeds.
●After the hybrid system is restarted at less than -22°F (-30°C).
■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating when
there is frequent steering input over an extended period of time. The steering wheel
may feel heavy as a result. Should this occur, refrain from excessive steering input or
stop the vehicle and turn the hybrid system OFF. The system should return to nor-
mal within 10 minutes.
CAUTION
Any of the following conditions may result in an accident which could cause death or
serious injury:
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded.
●The vehicle hydroplanes while driving at high speed on the wet or slick road.
■Stopping distance when the ABS is op erating on the wet or slick roads
The ABS is not designed to shorten the ve hicle’s stopping distance. Always main-
tain a safe distance from the vehicle in front of you in the following situations.
●When driving on dirt, gravel or snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes or roads with uneven roads
■TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC is operating. 
Do not drive the vehicle in conditions where stability and power may be lost.

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3-7. Other interior features
Seat heaters (if equipped)
■The seat heaters can be used when
The power switch is in “IG-ON” mode.
■When not in use
Set the dial to “0”. The indicator light turns off.
CAUTION
■Burns
●Use caution when seating the following persons in a seat with the seat heater on
to avoid the possibility of burns:
• Babies, small children, the elderly, the sick and the disabled
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drug s that induce sleep (sleeping drugs,
cold remedies, etc.)
●Do not cover the seat with anything when using the seat heater. 
Using the seat heater with a blanket or cushion increases the temperature of the
seat and may lead to overheating.
Heats the seats
The indicator light comes on. 
The higher the number, the
w
armer the seats become.

326
3-7. Other interior features
Seat heaters and ventilators (if equipped)
■The seat heaters and ventilators can be used when
The power switch is in “IG-ON” mode.
■When not in use
Set the dial to “0”. The indicator light turns off.
CAUTION
■Burns
●Use caution when seating the following persons in a seat with the seat heater on
to avoid the possibility of burns:
• Babies, small children, the elderly, the sick and the disabled
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drug s that induce sleep (sleeping drugs,
cold remedies, etc.)
●Do not cover the seat with anything when using the seat heater. 
Using the seat heater with a blanket or cushion increases the temperature of the
seat and may lead to overheating.
The seat heaters and ventilators heat the seats and maintain good airflow
by blowing air from the seats.
Heats the seats
The indicator light (red) comes
on. 
The higher the number, the
w
armer the seats become.
Blows air from the seats
The indicator light (green)
comes on. 
The higher the number, the
str
onger the airflow becomes.

476
5-2. Steps to take in an emergency
■Overheating
In the following situations, your vehicle may be overheating.
●The message “HYBRID SYSTEM OVERHEAT” is displayed on the multi-infor-
mation display.
●The engine coolant temperatur e gauge enters the red zone or a loss of power is
experienced.
●Steam is coming from under the hood.
CAUTION
■To prevent an accident or injury when in specting under the hood of your vehicle
●Keep hands and clothing away from the fan and engine drive belt while the hybrid
system is running.
●Do not loosen the radiator cap while the hybrid system and radiator are hot. 
Serious injury, such as burns, may resu lt from hot coolant and steam released
under pressure.
Add coolant if required.
Water can be used in an emer -
gency measure if coolant is
una
vailable. ( P. 4 8 4 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos -
sible.
STEP6

511
Alphabetical index
Installing CRS with lower 
anchorages .......................................... 87
Installing CRS with seatbelts .......... 83
Installing CRS with top straps ........ 88
Child safety Airbag precautions .............................. 75
Child restraint system ........................ 80
Child-protectors.................................... 27
How your child should wear 
the seatbelt ........................................... 45
Installing child restraints .................... 83
Moon roof ................................................. 57
Power window lock switch .............. 52
Power window precautions............ 54
Removed electronic key battery 
precautions ....................................... 394
Seat belt comfort guide...................... 43
Seat belt precautions...........................46
Seat heater precautions ..... 324, 326
Trunk ............................................................ 33
Cigarette lighter .................................... 322
Cleaning Exterior ................................................... 344
Interior..................................................... 346
Seat belts ................................................ 347
Clock........................................................... 319
Coin holder .............................................. 314
Compass ................................................. 339
Condenser.............................................. 369
Console box ............................................. 312
Cooling system Engine overheating .......................... 475Cruise control
Cruise control........................................ 127
Dynamic radar cruise control....... 130
Cup holders ............................................. 315
Curtain shield airbags............................ 69
Customizable features ...................... 500
Daytime running light system ............. 121
Defogger Rear window ......................................... 199
Side mirror.............................................. 199
Dimension............................................... 480
Dinghy towing ......................................... 180
Display Energy flow ................................................. 6
Multi-informatio n display
..................117
Touch screen ........................................ 182
Trip information ..................................... 118
Warning message ............................. 436
Do-it-yourself maintenance ............. 355
Door courtesy lights ........................... 308
Door pocket............................................. 316
Doors
Door lock .................................................. 26
Rear door child protector ................ 27
Driver's seat belt reminder light ..... 433
Driving Correct posture..................................... 67
Procedures .............................................. 94
DVD player/changer.......................... 232
Electronic key Replacing battery ............................... 393
When the electronic key battery 
is discharged.................................... 469
D
E

512
Alphabetical index
Emergency, in case ofIf a warning light turns on .............. 430
If a warning message is 
displayed ............................................ 436
If the hybrid system will not 
start........................................................ 466
If the shift lever cannot be 
shifted from P ................................... 467
If the 12 volt battery is 
discharged ......................................... 471
If you have a flat tire ............ 455, 456
If you lose your keys......................... 468
If you think something is 
wrong ....................................................427
If your vehicle becomes stuck..... 478
If your vehicle needs to be 
towed ................................................... 420
If your vehicle overheats ................ 475
When the electronic key battery 
is discharged .................................... 469
Energy monitor............................................ 6
Engine Compartment ....................................... 361
Hood........................................................ 358
How to start the hybrid system
.....101
If the hybrid system will not 
start........................................................ 466
Overheating......................................... 475
Power switch .......................................... 101
Engine compartment cover ............. 362
Engine coolant temperature 
gauge.........................................................110
Engine/inverter coolant Capacity ................................................. 484
Checking ............................................... 368
Preparing and checking 
before winter ...................................... 174 Engine oil
Capacity ................................................ 483
Checking............................................... 363
Preparing and checking  before winter...................................... 174
Engine oil maintenance data ........... 366
EPS (Electric Power Steering) ......... 162
Event data recorder ............................ 428
First-aid kit storage belt ..................... 332
Floor mats .................................................. 331
Fluid Brake ....................................................... 370
Washer.................................................... 374
Fog lights Switch ........................................................ 123
Wattage ................................................. 488
Foot light .................................................. 308
Front passenger's seat
belt 
reminder light ..................................... 433
Front seats Adjustment ............................................... 34
Driving position memory .................. 36
Front turn signal lights Wattage ................................................. 488
Fuel Capacity ................................................ 482
Fuel gauge ................................................ 110
Gas station information ................. 520
Information ........................................... 489
Refueling ................................................... 58
Messages .............................................. 450
Fuel filler door ........................................... 58
Fuses .......................................................... 395
F