engine overheat Lexus GS450h 2007 Using the hands-free system (for cellular phone) / LEXUS 2007 GS450H THROUGH JUNE 2006 PROD. OWNER'S MANUAL (OM30727U)

97
2-1. Driving procedures
2
When driving
CAUTION
■When driving the vehicle
●Do not under any circumstances shift the shift lever to “P”, “R” or “N” while the
vehicle is moving. 
Doing so can cause significant damage to the transmission and may result in a
loss of vehicle control.
●Do not shift the shift lever to “N” while the vehicle is moving. 
Doing so may cause the engine brake not to operate properly and lead to an
accident.
●Do not turn the hybrid system off while driving. 
The brake actuator will not operate properly if the hybrid system is off.
●Use engine braking (downshift) to maintain a safe speed when driving down a
steep hill. 
Using the brakes continuously may cause the brakes to overheat and lose effec-
tiveness. ( P. 1 0 6 )
●When stopped on an inclined surface, use the brake pedal and parking brake to
prevent the vehicle from rolling backward or forward and causing an accident.
●Be careful when driving on slippery surfaces, as the vehicle may spin or skid when
downshifting, rapidly accelerating, braking or turning.
●Do not adjust the position of the steering wheel, the seat, or the inside or outside
rear view mirrors while driving. 
Doing so may result in a loss of vehicle control that can cause accidents that may
result in death or serious injury.
●Always check that all passengers' arms, heads or other parts of their bodies are
not outside the vehicle, as this may result in death or serious injury.

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.

5
When trouble arises
475
5-2. Steps to take in an emergency
If your vehicle overheats
■Electric motor (traction motor) and inverter
If the message “HYBRID SYSTEM OVERHEAT” is displayed on the
multi-information display.
■ Ga
soline engine
If the needle of the engine co olant temper
ature gauge enters the
red zone, the gasoline engine has probably overheated.
Observe the following steps: Stop the vehicle in a safe place and turn of
f the automatic air
conditioning system.
Check to see if steam is coming out from under the hood.
If you see steam: 
Stop the hybrid system and carefully lift the hood.
If you do not see steam: Leave the hybrid system running and carefully lift the hood.
Remove the engine compartment cover. ( P. 362 )
Check to see if the cooling fan is operating.
If the fan is operating: 
Wait until the engine coolant temperature gauge begins to
fall and then stop the hybrid s
ystem.
If the fan is not operating: 
Stop the hybrid system immed iately and call y
our local
Lexus dealer.
After the hybrid system has
cooled do
wn sufficiently, check
the coolant level and inspect the
radiator core (radiator) for any
leaks.
STEP1
STEP2
STEP3
STEP4
STEP5

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

514
Alphabetical index
Turn signal lever ..................................108
Vanity lights ........................................... 318
Wattage................................................. 488
Maintenance Do-it-yourself maintenance ......... 355
General maintenance ....................... 351
Maintenance data............................. 480
Maintenance requirements .......... 349
Meter Instrument panel light control .......... 111
Meters ........................................................ 110
Micro dust and pollen removal 
mode ........................................................ 194
Mirrors Inside rear view mirror....................... 49
Side mirror heater ............................... 199
Side mirrors ............................................. 50
Vanity mirrors....................................... 318
Moon roof ................................................... 55
MP3 disc ..
.................................................... 224
Multi-information display ........
................117
Odometer................................................... 110
Oil Engine oil ............................................... 363
Opener Fuel filler door......................................... 58
Hood........................................................ 358
Trunk ........................................................... 30
Outside rear view mirrors Adjusting and folding ......................... 50
Driving position memory.................. 36
Outside temperature display........... 320
Overhead console ................................ 313
Overheating, Engine .......
......................475 Parking brake..........................................
109
Parking lights Replacing light bulbs ......................... 413
Switch ........................................................ 120
Wattage ................................................. 488
PCS (Pre-Collision System) .............. 163
Personal lights........................................ 309
Power meter.............................................. 110
Power outlet ........................................... 323
Power windows ........................................ 52
Radar cruise control............................. 130
Radiator .................................................... 369
Radio .........
..................................................... 203
RDS (Radio Date System) ................ 205
Rear sunshade ....................................... 329
Rear turn signal lights Replacing light bulbs ......................... 413
Wattage ................................................. 488
Rear view monitor system ................. 158
Rear window defogger ........................ 199
Replacing Electronic key battery ..................... 393
Fuses ........................................................ 395
Light bulbs .............................................. 413
Reporting safety defects for 
U.S.A. owners .....................................508
Seat belts Adjusting the seat belt ........................ 43
Automatic Locking Retractor 
(ALR) ....................................................... 44
Child restraint system 
installation ............................................. 83
Cleaning and maintaining 
the seat belts .....................................347
M
O
P
R
S

518
What to do if...
What to do if...
A tire puncturesP. 4 5 5 /
456If you have a flat tire
The hybrid system does not start
P. 6 2Hybrid vehicle immobilizer system
P. 4 6 6If the hybrid system will not start
P. 4 7 1If the 12 volt battery is discharged
The shift lever cannot be 
moved outP. 4 6 7If the shift lever cannot be shifted 
from “P”
The engine coolant temperature
gauge enters the red zone
Steam can be seen coming 
from under the hood
P. 4 7 5If your vehicle overheats
The key is lostP. 4 6 8If you lose your keys
The battery runs outP. 4 7 1If the 12 volt battery is discharged
The doors cannot be lockedP. 2 6Doors
The horn begins to soundP. 6 4Alarm
The vehicle is stuck in mud or
sandP. 4 7 8If the vehicle becomes stuck