2015 Lexus IS300h overheating

1142. Instrument cluster
IS300h_EE(OM53D56E)
■Tachometer
Hybrid System Indicator switches to the tachometer when driving mode is in sport mode.
The settings of the tachometer display can be changed on the multi-information display.
( → P. 1 1 8 )
■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 vehicle
operation and driving co nditions are the same.
■Outside temperature display
In the following situations, the correct outside temperature may not be displayed, or the
display may take longer than normal to change.
●When stopped, or driving at low sp eeds (less than 20 km/h [12 mph])
●When the outside temperature has changed su ddenly (at the entrance/exit of a garage,
tunnel, etc.)
■Po p - u p d i s p l a y
In some situations, a pop-up display will be temporarily displayed on the multi-informa-
tion display or the odometer/trip me ter screen (F SPORT models only).
The pop-up display function can be set on/off. ( →P. 1 1 8 )
■Liquid crystal display
Small spots or light spots may appear on the display. This phenomenon is characteristic
of liquid crystal displays, and there is no problem continuing to use the display.
■Customization
The meter display can be customized on the multi-information display. ( →P. 1 1 5 )
NOTICE
■To prevent damage to the engine and its components
●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 7 1 )

2004-1. Before driving
IS300h_EE(OM53D56E)
CAUTION
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.

2104-1. Before driving
IS300h_EE(OM53D56E)
■Important points regarding stability
Vehicle movement resulting from uneven road surfaces and strong cross-
winds will affect handling. The vehicle may also be rocked by passing buses or
large trucks. Frequently check behind when moving alongside such vehicles.
As soon as such vehicle movement occurs, immediately start to decelerate
smoothly by slowly applying the brakes. Always steer the vehicle straight
ahead while braking.
■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 downward grade, do not use the transmission in D. The
vehicle must be driven in gear shift position “4” in S mode. ( →P. 222)
■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 7 1 )
■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.

2114-1. Before driving
4
Driving
IS300h_EE(OM53D56E)
CAUTION
■To avoid accident or injury
Do not tow a trailer when a tire installed is repaired with the emergency tire puncture
repair kit.
■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.
NOTICE
■For vehicles with an emergency tire puncture repair kit (if equipped)
Do not tow anything if a tire that has been repaired using the emergency tire puncture
repair kit is installed. The load on the tire may cause unexpected damage to the tire.

2154-2. Driving procedures
4
Driving
IS300h_EE(OM53D56E)
■Steering lock
After turning the power switch off and opening and closing the doors, the steering wheel
will be locked due to the steering lock function. Operating the power switch again auto-
matically cancels the steering lock.
■When the steering lock cannot be released
■Steering lock motor overheating prevention
To prevent the steering lock motor from overheating, operation of the motor may be sus-
pended if the hybrid system is turned on an d 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” is 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
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 any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional immediately.
■If the hybrid system is malfunctioning
→ P. 5 3 0
■If the electronic key battery is depleted
→P. 5 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 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 by a customized setting
→P. 5 6 3
“Steering Lock active” w
ill be displayed on the
multi-information display.
Check that the shift lever is in P. Press the power
switch while turning the steering wheel left and
right.

2994-5. Using the driving support systems
4
Driving
IS300h_EE(OM53D56E)
■When the 12-volt battery is disconnected
The steering wheel may move from its straight forward position, but this will be corrected
automatically when driving.
■Sounds and vibrations caused by the ABS, brake assist, TRC, VSC, hill-start assist con-
trol systems
●A sound may be heard from the engine compartment when the brake pedal is
depressed repeatedly, when the hybrid system is started or just after the vehicle begins
to move. This sound does not indicate that a malfunction has occurred in any of these
systems.
●Any of the following conditions may occu r 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.
■EPS operation sound
When the steering wheel is operated, a motor sound may be heard. This does not indi-
cate 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 the 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.

4236-1. Using the air conditioning system
6
Interior features
IS300h_EE(OM53D56E)
Turn the heated steering wheel on/off
The indicator light comes on when the
heated steering wheel is operating.
Heated steering wheel∗/seat heaters∗/seat ventila-
tors
∗
∗
: 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.
CAUTION
●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
●Do not put heavy objects that have an uneven surface on the seat and do not stick
sharp objects (needles, na ils, etc.) into the seat.
●To prevent 12-volt battery discharge, do not use the functions when the hybrid system
is off.
Heated steering wheel

5718-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
●The needle of the engine coolant temperature gauge (→P. 109) enters the
red zone or a loss of hybrid system power is experienced. (For example, the
vehicle speed does not increase.)
●“Hybrid System Overheat” 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
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 radiator core (radi-
ator) for any 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 coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
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