2015 Lexus GS450h overheating

801-2. Hybrid system
GS450h_OM_OM30F70U_(U)
CAUTION
■Hybrid battery (traction battery)
●Your vehicle contains a sealed nickel-metal hydride battery. Never resell, hand
over or modify the hybrid battery. To prevent accidents, hybrid batteries that have
been removed from a disposed vehicle are collected through Lexus dealer. Do
not dispose of the battery yourself.
Unless the battery is properly collected, the following may occur, resulting in
death or serious injury:
• The hybrid battery may be illegally disp osed of or dumped, and it is hazardous
to the environment or someone may touch a high voltage part, resulting in an
electric shock.
• The hybrid battery is intended to be used exclusively with your hybrid vehicle. If the hybrid battery is used outside of your vehicle or modified in any way,
accidents such as electric shock, heat generation, smoke generation, an
explosion and electrolyte leakage may occur.
When reselling or handing over your vehicle, the possibility of an accident is
extremely high because the person rece iving the vehicle may not be aware of
these dangers.
●If your vehicle is disposed of without the hybrid battery having been removed,
there is a danger of serious electric shock if high voltage parts, cables and their
connectors are touched. In the event that your vehicle must be disposed of, the
hybrid battery must be disposed of by your Lexus dealer or a qualified service
shop. If the hybrid battery is not disposed of properly, it may cause electric shock
that can result in death or serious injury.
NOTICE
■Hybrid battery air vents
●Do not put foreign objects near the air vents. The hybrid battery (traction battery)
may overheat and be damaged.
●Clean the air vents regularly to prevent the hybrid battery (traction battery) from
overheating.
●Do not wet or allow foreign substances to enter the air vents as this may cause a
short circuit and damage the h ybrid battery (traction battery).
●Do not carry large amounts of water such as water cooler bottles in the vehicle. If
water spills onto the hybrid battery (t raction battery), the battery may be dam-
aged. Have the vehicle inspected by your Lexus dealer.

GS450h_OM_OM30F70U_(U)
952. Instrument cluster
2
Instrument cluster
■ECO lamp and SPORT lamp
●When sport mode is selected, SPORT lamp (red) will illuminate.
●When all of the following conditions are satisfied and Eco-friendly driving, ECO
lamp (blue) will illuminate. (ECO lamp will become brighter the more Eco-friendly
driving you perform. Also, while the vehicle is stopped or the acceleration exceeds
Zone of Eco driving, ECO lamp turns off. [P. 9 4 ] H o w e v e r, w h e n E c o d r i v e
mode is selected, while the vehicle is stopped or the acceleration exceeds Zone of
Eco driving, ECO lamp does not turn off.):
• Driving with the shift lever in D
• Paddle shift switch is not operated.
• Either normal mode or Eco drive mode is selected.
• The vehicle speed is approximately 80 mph (130 km/h) or below.
■Tachometer
Hybrid System Indicator switches to the ta chometer when driving mode is in sport
mode.
■Engine speed
On hybrid vehicles, engine speed is precis ely controlled in order to help improve
fuel efficiency and reduce exhaust emissions etc.
There are times when the engine speed that is displayed may differ even when vehi-
cle operation and driving conditions are the same.
■Customization
Settings (e.g. on/off operatio n of ECO lamp) can be changed.
(Customizable features: P. 5 9 9 )
NOTICE
■To prevent damage to the engine and its components
●Do not let the indicator needle of the tachometer enter the red zone, which indi-
cates the maximum engine speed.
●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, and check
the engine after it has cooled completely. ( P. 566)

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GS450h_OM_OM30F70U_(U)
4-1. Before driving
CAUTION
■When taking a nap in the vehicle
Always turn the hybrid system off. Otherwise, if you accidentally move the shift
lever or depress the accelerator pedal, this could cause an accident or fire due to
hybrid system overheating. Additionally, if the vehicle is parked in a poorly venti-
lated area, exhaust gases may collect and enter the vehicle, leading to death or a
serious health hazard.
■When braking
●When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and this may cause one side
of the vehicle to brake differently than the other side. Also, the parking brake may
not securely hold the vehicle.
●If the electronically controlled brake system does not operate, do not follow other
vehicles closely and avoid hills or sharp turns that require braking.
In this case, braking is still possible, but the brake pedal should be depressed
more firmly than usual. Also, the braking distance will increase. Have your brakes
fixed immediately.
●The brake system consists of 2 or more individual hydraulic systems; if one of the
systems fails, the other(s) will still operate. In this case, the brake pedal should be
depressed more firmly than usual and th e braking distance will increase. Have
your brakes fixed immediately.

GS450h_OM_OM30F70U_(U)
1974-2. Driving procedures
4
Driving
■When the steering lock cannot be released
■Steering lock motor overheating prevention
To prevent the steering lock motor from overheating, the motor may be suspended if
the hybrid system is turned on and off repeatedly in a short period of time. In this
case, refrain from operating the hybrid sy stem. After about 10 seconds, the steering
lock motor will resume functioning.
■When “Check Access System with Elec. Key” will be displayed on the multi-infor-
mation display
The system may be malfunctio ning. Have the vehicle inspected by your Lexus dealer
immediately.
■If the “READY” indicator does not come on
If the “READY” indicator does not come on when you press the power switch with
the shift lever in P and the brake pedal depressed, contact your Lexus dealer imme-
diately.
■If the hybrid system is malfunctioning
 P. 5 1 4
■If the electronic key battery is depleted
P. 4 6 0
■Operation of the power switch
●When operating the power switch, one short, firm press is enough. If the switch is
pressed improperly, the hybrid system may not start or the power switch mode may
not change. It is not necessary to press and hold the switch.
●If attempting to restart the hybrid sy stem immediately after turning the power
switch off, the hybrid system may not star t in some cases. After turning the power
switch off, please wait a few seconds before restarting the hybrid system.
■If the smart access system with push-but ton start has been deactivated in a cus-
tomized setting
 P. 559
“Steering Lock active” will be displayed on
the multi-information display.
Check that the shift lever is set in P. Press the
power switch while turning the steering wheel
left and right.

384
GS450h_OM_OM30F70U_(U)
5-5. Other interior features
■When the switch is disabled (vehicles with rear control panel)
When the rear control panel switch cannot be operated even though the button lock
function is released, check whether the switch is disabled due to selecting
on Remote Touch screen. (P. 3 4 8 )
■Rear control panel illumination off function (vehicles with rear control panel)
Control panel illumination on the rear armrest can be turned off. ( P. 3 5 9 )
■Customization
The automatic mode settings for the front seat heaters and ventilators or the rear
seat heaters can be changed. (Customizable features: P. 599)
CAUTION
■Burns
●Use caution when seating the following pers ons in a seat with the seat heater on
to avoid the possibility of burns:
• Babies, small children, the elderly, the sick and the physically challenged
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drugs 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.
●Do not use seat heater more than necessary. Doing so may cause minor burns or
overheating.

5327-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
*: Refer to the separate “Scheduled Maintenance” or “Owner’s Manual Supple-ment” for the maintenance interval applicable to your vehicle.
Wa r n i n g m e s s a g eDetailsCorrection procedure
Indicates that the tire
position information can-
not be recognized
Drive for a short while
and check if the display
updates. If the radio wave condi-
tions improve, the dis-
play may return to
normal. If the tire pres-
sure is still not dis-
played after driving for
several minutes, stop
the vehicle in a safe
place, turn the power
switch off then on
again, and start driving.
If the tire pressure is still
not displayed even
after repeating this sev-
eral times, have the
vehicle inspected at
your Lexus dealer.
Indicates that the pre-col-
lision system is not cur-
rently functional because
the grille cover or the
sensor is dirtyThis message also
appears when the pre-
collision system is not
functional due to over-
heating.
• Check the grille coverand the sensor and
clean them if they are
dirty.
• In case of overheating, the system will become
functional once the sys-
tem cools down.
(If equipped)
(Flashes)
(If equipped)

566
GS450h_OM_OM30F70U_(U)
7-2. Steps to take in an emergency
If your vehicle overheats
■If the needle of the engine coolant temperature gauge enters the red
zone
Stop the vehicle in a safe place an d turn off the air conditioning sys-
tem, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has cooled down sufficiently, inspect the
hoses and cooling system for leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact your
Lexus dealer.
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( P. 91) enters
the red zone or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
●“Hybrid System Overheat” ( P. 527) is shown on the multi-informa-
tion display.
●Steam comes out from under the hood.
Correction procedures
1
2
3
1
2

636Alphabetical index
GS450h_OM_OM30F70U_(U)
Child restraint system............................ 57Booster seats, definition .................... 57
Booster seats, installation.................. 67
Convertible seats, definition ............ 57
Convertible seats, installation ......... 64
Front passenger occupant classification system ......................... 49
Infant seats, definition .......................... 57
Infant seats, installation ....................... 64
Installing CRS with LATCH anchors ..................... 62
Installing CRS with seat belts .......... 64
Installing CRS with top tether strap .........................68
Child safety ................................................ 56 12-volt battery precautions ............................. 441, 565
Airbag precautions ................................41
Child restraint system ......................... 57
How your child should wear the seat belt ................................. 33, 35
Installing child restraints.......................61
Moon roof precautions.....................174
Power window lock switch .............167
Power window precautions .......... 170
Rear door child-protectors ........... 140
Removed electronic key battery precautions................ 461
Seat belt comfort guide ..................... 33
Seat belt extender precautions ...... 37
Seat belt precautions ..........................60
Seat heater precautions................. 384
Trunk precautions............................... 146 Child-protectors .................................... 140
Cleaning ........................................ 408, 412
Aluminum wheels ..............................409
Exterior .................................................. 408
Interior ....................................................... 412
Seat belts.................................................. 413
Clock..........................................................376
Coat hooks ............................................. 390
Condenser.............................................. 436
Console box ........................................... 369
Console box light ................................. 369
Consumption screen ..............................114
Coolant .....................................................434 Capacity................................................. 579
Checking ............................................... 434
Preparing and checking before winter..................................................... 318
Cooling system ......................................434 Engine overheating ..........................566
Hybrid system overheating ..........566
Cruise control Cruise control ..................................... 235
Dynamic radar cruise control ..... 239
Dynamic radar cruise control with full-speed range ................... 254
Cup holders............................................ 370
Curtain shield airbags ............................39
Customizable features ...................... 599