overheating Lexus GS300h 2016 Owner's Manual

831-2. Hybrid system
1
GS450h_300h_OM_OM30F00E_(EE)
For safety and security
WA R N I N G
■Hybrid battery (traction 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 any
authorized Lexus dealer or repairer, or another duly qualified and equipped profes-
sional. Do not dispose of the battery yourself.
Unless the battery is properly collected, th e following may occur, resulting in death
or serious injury:
• The hybrid battery may be illegally dispos ed 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 elec-
trolyte leakage may occur.
When reselling or handing over your vehi cle, the possibility of an accident is
extremely high because the person receiving 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 any authorized Lexus dealer or repairer, or another duly qual-
ified and equipped professional. If the hybrid battery is not disposed of properly, it
may cause electric shock that can re sult in death or serious injury.
NOTICE
■Hybrid battery (traction battery) air intake vents
●Do not place objects that will block the air intake vents. The hybrid battery (traction
battery) may overheat and be damaged.
●Clean the air intake vents regularly to prevent the hybrid battery (traction battery)
from overheating.
●Do not get water or foreign materials in the air intake vents as this may cause a short
circuit and damage the hybrid 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 (tract ion battery), the battery may be damaged.
Have the vehicle inspected by any authorized Lexus dealer or repairer, or another
duly qualified and equipped professional.

1102. Instrument cluster
GS450h_300h_OM_OM30F00E_(EE)
WA R N I N G
■The information display at low temperatures
Allow the interior of the vehicle to warm up before using the liquid crystal information
display. At extremely low temperatures, the information display monitor may respond
slowly, and display changes may be delayed.
For example, there is a lag between the driver’s shifting and the new gear number
appearing on the display. This lag could cause the driver to downshift again, causing
rapid and excessive engine braking and possibly an accident resulting in death or
injury.
NOTICE
■To prevent damage to the hybrid system and its components
●While the tachometer is displayed, do not let the indicator needle of the tachometer
enter the red zone, which indicates 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. 5 5 6 )

2064-1. Before driving
GS450h_300h_OM_OM30F00E_(EE)
WA R N I N G
Observe the following precautions.
Failure to do so may result in death or serious injury.
■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 ventilated 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, th e braking distance will increase. Have your brakes fixed
immediately.
●The brake system consists of 2 or more individual hydraulic systems; if one of the sys-
tems fails, the other(s) will still operate. In this case, the brake pedal should be
depressed more firmly than usual and the braking distance will increase. Have your
brakes fixed immediately.
■If the vehicle becomes stuck
Do not spin the wheels excessively when any of the tires is up in the air, or the vehicle is
stuck in sand, mud, etc. This may damage the driveline components or propel the vehi-
cle forward or backward, causing an accident.

2154-1. Before driving
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
■Passing other vehicles
Consider the total combined length of your vehicle and trailer and ensure that
the vehicle-to-vehicle distance is sufficient before executing lane changes.
■Transmission information
To maintain engine braking efficiency, when using engine braking, when driv-
ing on a long steep downgrade, do not use the transmission in D. ( →P. 2 2 7 )
■If the engine overheats
Towing a loaded trailer up a long, steep incline in temperatures exceeding
30 °C (85 °F) may result in the engine overheating. If the engine coolant tem-
perature gauge indicates that the engine is overheating, turn the air condition-
ing off immediately, leave the road and stop the vehicle in a safe place.
( → P. 5 5 6 )
■When parking the vehicle
Always place wheel chocks under the whee ls of both the vehicle and trailer.
Firmly set the parking brake and shift the shift lever to P.
WA R N I N G
Follow all the instructions described in this section. Failure to do so could cause an acci-
dent resulting in death or serious injury.
■Trailer towing precautions
When towing, make sure that none of the weight limits are exceeded. ( →P. 211)
■To avoid accident or injury
●Do not tow a trailer when the compact spare tire is installed on your vehicle.
●Do not tow a trailer when the tire installed is repaired with the emergency tire punc-
ture repair kit.
●Do not use cruise control (if equipped), dynamic radar cruise control (if equipped) or
dynamic radar cruise control with full-speed range (if equipped) when trailer towing.
■Vehicle speed in towing
Observe the legal maximum speeds for trailer towing.
■Before descending hills or long declines
Reduce speed and downshift. However, never downshift suddenly while descending
steep or long downhill grades.
■Operation of the brake pedal
Do not hold the brake pedal depressed often or for long periods of time.
Doing so may result in the brake overheating or reduce braking effects.

2204-2. Driving procedures
GS450h_300h_OM_OM30F00E_(EE)
■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 system. After about 10 seconds, the steering lock motor will
resume functioning.
■When “Check Entry & Start System” will be displayed on the multi-information display
The system may be malfunctioning. Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional immediately.
■If the “READY” indicator does not come on
In the event that the “READY” indicator does not come on even after performing the
proper procedures for starting the vehicle, contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional immediately.
■If the hybrid system is malfunctioning
→ P. 4 8 2
■If the electronic key battery is depleted
→P. 4 5 1
■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 no t 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 system immediately after turning the power switch off,
the hybrid system may not start in some cases. After turning the power switch off,
please wait a few seconds before restarting the hybrid system.
■If the smart entry & start system has been deactivated in a customized setting
→P. 5 4 8
“Steering Lock active” w
ill 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.

2324-2. Driving procedures
GS450h_300h_OM_OM30F00E_(EE)
■Parking brake operation
●When the power switch is not in ON mode, the parking brake cannot be released using
the parking brake switch.
●When the power switch is not in ON mode, automatic mode (automatic brake setting
and releasing) is not available.
●If the parking brake is operated repeatedly over a short period of time, the system may
restrict operation to prevent overheating. If this happens, refrain from operating the
parking brake. Normal operation will return after about 1 minute.
●Vehicles with towing package: In situations such as when parking while towing a trailer,
the maximum amount of braking force can be used by pressing the parking brake
switch with the parking brake already set.
●Vehicles without towing package: In situations such as when parking on a steep slope*,
the maximum amount of braking force can be used by pressing the parking brake
switch with the parking brake already set.
*: Use wheel chocks when parking on a steep slope.
■Parking brake operation sound
When the parking brake operates, a motor sound (whirring sound) may be heard. This
does not indicate a malfunction.
■Parking brake indicator light
●Depending on the power switch mode, the parking brake indicator light will come on
and stay on as described below:
ON mode: Comes on until the parking brake is released.
Not in ON mode: Stays on for approximately 15 seconds.
●When the power switch is turned off with the parking brake set, the parking brake indi-
cator light will stay on for about 15 seco nds. This does not indicate a malfunction.
■When there is a malfunction in the system
Warning lights and/or warning message will turn on or flash. (→P. 4 7 8 , 4 8 2 )
Depending on the condition, the park ing brake indicator light may flash.
■Parking brake engaged warning buzzer
→P. 4 8 8
■Usage in winter time
→P. 3 5 4

3484-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
■Sounds and vibrations caused by the ABS, brake assist, VSC, Hill-start assist control,
TRC and VGRS systems
Any of the following conditions may occur when the above systems are operating. None
of these indicates that a malfunction has occurred.
●Vibrations may be felt through the vehicle body and steering.
●A motor sound may be heard after the vehicle comes to a stop.
■ECB operation sound
ECB operating sound may be heard in the following cases, but it does not indicate that a
malfunction has occurred.
●Operating sound heard from the engine compartment when the brake pedal is oper-
ated.
●Motor sounds of the brake system heard from the front part of the vehicle when the
driver’s door is opened.
●Operating sound heard from the engine compartment when one or two minutes
passed after the stop of the hybrid system.
■EPS, VGRS and DRS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
■Automatic reactivation of TRC and VSC systems
After turning the TRC and VSC systems off, the systems will be automatically re-enabled
in the following situations:
●When the power switch is turned off
●If only the TRC system is turned off, the TRC will turn on when vehicle speed increases
If both TRC and VSC systems are turned off, automatic re-enabling will not occur when
vehicle speed increases.
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system 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 EPS system should return to nor-
mal within 10 minutes.
■Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate;
●The shift lever is in a position other than N or P (when starting off forward/backward on
an upward incline).
●The vehicle is stopped.
●The accelerator pedal is not depressed.
●The parking brake is not engaged.

381
5
5-2. Using the air conditioning system and defogger
Interior features
GS450h_300h_OM_OM30F00E_(EE)
Heated steering wheel∗/seat heaters∗/seat ventilators∗
∗: If equipped
Heated steering wheel and seat heaters heat the side grips of the steering
wheel and seats, respectively. Seat ventilators maintain good airflow by blow-
ing air from the seats.
WA R N I N G
●Care should be taken to prevent injury if
anyone in the following categories comes in
contact with the steering wheel and seats when the heater is on:
• 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.)
●Observe the following precautions to prevent minor burns or overheating:
• Do not cover the seat with a blanket or cushion when using the seat heater.
• Do not use seat heater more than necessary.
NOTICE
●To prevent damage to the seat heaters/seat ventilators, do not put heavy objects that
have an uneven surface on the seat and do not stick sharp objects (needles, nails, etc.)
into the seat.
●To prevent 12-volt battery discharge, do not use the functions when the hybrid system
is off.

4917-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F00E_(EE)
Indicates that the parking brake system is overheatingA buzzer also sounds.
→ Do not use the parking brake until the message dis-
appears.
Indicates an engine malfunction
A buzzer also sounds.
→ Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and
equipped professional.
Indicates an engine malfunction
A buzzer also sounds.
→ Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and
equipped professional.
Indicates a malfunction in:
• The SRS airbag system; or
• The seat belt pretensioner system
A buzzer also sounds.
→ Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and
equipped professional.
Wa r n i n g m e s s a g eDetails/Actions

5567-2. Steps to take in an emergency
GS450h_300h_OM_OM30F00E_(EE)
If your vehicle overheats
●The needle of the engine coolant temperature gauge ( →P. 104) enters the
red zone or a loss of hybrid system power is experienced. (For example, 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” ( →P. 482) is shown on
the multi-information display.
●Steam comes out from under the hood.
■If the needle of 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
Stop the vehicle in a safe place and turn off the air conditioning system, 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 any autho-
rized Lexus dealer or repairer, or
another duly qualified and
equipped professional.
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2