2015 LEXUS RX450h overheating

381-1. Hybrid system
CAUTION●
If your vehicle needs to be towed, do so with all front wheels (for 2WD models) or
four wheels (for AWD models) raised. If the wheels connected to the electric
motor (traction motor) are on the ground when towing, the motor may continue
to generate electricity. This may cause an electricity leakage leading to a fire.
(
 P. 7 2 5 )●
Carefully inspect the ground under the vehicle. If you find that liquid has leaked
onto the ground, the fuel system may have been damaged. Leave the vehicle as
soon as possible.■
Nickel-metal hydride battery
Your vehicle contains a sealed nickel-metal hydride battery. If disposed of improp-
erly, it is hazardous to the environment and there is a risk of severe burns and elec-
trical shock that may result in death or serious injury.■
Emergency shut off system
Carefully check to see if there are exposed high voltage parts or cables. Never
touch the parts or cables. (
 P. 3 4 )
NOTICE■
Hybrid battery air vents ●
Do not put foreign objects over the air vents. The hybrid battery (traction battery)
may overheat or lose power 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 hybrid battery (traction battery).●
Do not carry large amounts of water such as an aquarium into the vehicle. If water
spills onto the hybrid battery (tractio n battery), the battery may be damaged.
Have the vehicle inspected by your Lexus dealer.

1742-1. Driving procedures
CAUTION■
Exhaust gases
Exhaust gases include harmfu l carbon monoxide (CO) th at is colorless and odor-
less. Inhaling exhaust gases may lead to death or a serious health hazard. ●
If the vehicle is in a poorly ventilated area, stop the hybrid system. In a closed
area, such as a garage, exhaust gases may collect and enter the vehicle. This may
lead to death or a serious health hazard.●
The exhaust system should be checked occasionally. If there is a hole or crack
caused by corrosion, damage to a joint or abnormal exhaust noise, be sure to
have the vehicle inspected and repaired by your Lexus dealer . Failure to do so
may allow exhaust gases to enter the vehicl e, resulting in death or a serious health
hazard.■
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 the vehicle ●
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 syst em 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) wi ll 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.

1802-1. Driving procedures
■
Note for the entry function
 P. 6 3■
If the hybrid system does not start
The immobilizer system may not have been deactivated. (  P. 1 2 4 )
Contact your Lexus dealer.■
Steering lock
After turning the “POWER” switch off and opening and closing the doors, the
steering wheel will be locked due to th e steering lock function. Operating the
“POWER” switch again automatically cancels the steering lock.■
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 re peatedly in a short period of time. In this
case, refrain from operating the hybrid sy stem. After about 2 seconds, the steering
lock motor will resume functioning.■
When the “POWER” switch indicator flashes in amber
The system may be malfunctioning. 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 pe dal depressed, contact your Lexus dealer
immediately.
■
If the hybrid system is malfunctioning
 P. 74 4
■
If the electronic key battery is depleted
 P. 6 8 7 The green indicator light on the “POWER”
switch will flash and a message will be shown
on the multi-information display. Press the
“POWER” switch again while turning the
steering wheel left and right.

2002-2. Instrument cluster
NOTICE■
To prevent damage to the engine and its components
The engine may be overheating if the engi ne 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. 7 8 8 )

3172-5. Driving information
2
When driving ● Avoid jerky steering and sharp turns, and slow down before making a
turn.
● Note that when making a turn, the tr ailer wheels will be closer than the
vehicle wheels to the inside of th e turn. Compensate by making a
wider than normal turning radius.
● Slow down before making a turn, in cross winds, on wet or slippery sur-
faces, etc.
Increasing vehicle speed can destabilize the trailer.
● Take care when passing other vehi cles. Passing requires considerable
distance. After passing a vehicle, do not forget the length of your
trailer, and be sure you have plenty of room before changing lanes.
● To maintain engine braking efficiency and charging system perfor-
mance when using engine braking, do not put the transmission in D.
● Instability happens more frequently when descending steep or long
downhill grades. Before descending, slow down and downshift. Do not
make sudden downshifts while descending steep or long downhill
grades.
● Avoid holding the brake pedal down too long or applying the brakes
too frequently. This could cause th e brakes to overheat and result in
reduced braking efficiency.
● Due to the added load of the trailer, your vehicle’s engine may overheat
on hot days (at temperatures over 85°F [30°C]) when driving up a
long or steep grade. If the eng ine coolant temperature gauge indicates
overheating, immediately turn off th e air conditioning (if in use), pull
your vehicle off the road and stop in a safe spot. (  P. 7 8 8 )

6053-7. Other interior features
3
Interior features Seat heaters and ventilators 
■
Operating condition
The “POWER” switch is in ON mode.■
When not in use
Set the knob at “0”. The indicator light turns off.
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.
 : If equippedThe seat heaters and ventilators heat the seats and maintain good airflow
by blowing air from the seats.
Turns the seat heater on The indicator light comes on.
The higher the number is, the
warmer the seat becomes.
Blows air from the seat The indicator light comes on.
The higher the number is, the
stronger the airflow becomes.

5
When trouble arises
7515-2. Steps to take in an emergency
(If equipped) Indicates that the pre-
collision system is not
currently functional
because the grille or the
sensor is dirty.
This message also
appears when the pre-
collision system is not
functional due to over-
heating. • Check the grille and 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) Indicates that intuitive
parking assist is dirty or
covered with ice
A buzzer also sounds.
The site of the malfunc-
tion and the vehicle
image are flashing. Clean the sensor.
(If equipped) Indicates that the radar
cruise control sensor is
dirty or covered with ice
A buzzer also sounds. Clean the sensor.
(If equipped) Indicates that the radar
cruise control system is
unable to judge vehicle-
to-vehicle distance
A buzzer also sounds. • Switch driving mode to
normal.
• If the windshield wipers
are on, turn them off or
set them to a mode other
than AUTO (If
equipped) or high speed
wiper operation.Wa r n i n g m e s s a g e Details Correction procedure

7885-2. Steps to take in an emergency
If your vehicle overheats
Correction procedures
■ If “ENGINE OVERHEAT” 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 radiator core (radiator) for any
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.
● “ENGINE OVERHEAT” is shown on the multi-information display:
The engine may be overheating.
● “HYBRID SYSTEM OVERHEAT” is sh own on the multi-information
display:
A hybrid system component such as the power control unit or an
electric motor (traction motor) may be overheating.
● Steam comes out from under the hood. STEP 1
STEP 2
STEP 3