2021 LEXUS NX300h cooling

2955-2. Using the air conditioning system and defogger
LEXUS NX300h Owners Manual_USA_M78578_en
5
Interior features
minates on the screen.
Adjusting the temperature for
driver and passenger seats sepa-
rately (“DUAL” mode) (P.298)
Set eco air conditioning mode
Air conditioning and heater output is lim-
ited to prioritize fuel economy.
Cooling and dehumidification func-
tion
Select S-FLOW mode ( P.296)
Prevent ice from building up on the
windshield and wiper blades
(Windshield wiper de-icer) (if
equipped)
Removing pollen from the air
(Micro dust and pollen filter)
■Side display (Vehicles with naviga-
tion system)
Adjust the left-hand side tempera-
ture setting Adjust the fan speed setting
Adjust the right-hand side tem-
perature setting
Set cooling and dehumidification
function on/off
Adjust the temperature for the
driver’s and front passenger’s seats
separately (“DUAL” mode)
(
P.298)
Select the air flow mode
■Fogging up of the windows
●The windows will easily fog up when the
humidity in the vehicle is high. Pressing
“A/C” button or selecting “A/C” will
dehumidify the air from the outlets and
defog the windshield effectively.
●If you turn “A/C” off, the windows may
fog up more easily.
●The windows may fog up if the recircu-
lated air mode is used.
■Windshield wiper de-icer (if equipped)
This feature is used to prevent ice from
building up on the windshield and wiper
blades.
Select on the option control screen.
When the windshield wiper de-icer on, is displayed on the air conditioning
control screen.
The windshield wiper de-icer will automati-
cally turn off after a period of time.
■Eco air conditioning mode
When Eco mode is selected using the driv-
ing mode select switch, eco air conditioning
mode turns on. When a drive mode other
than Eco mode is selected, eco air condi-
tioning mode may turn off.
■S-FLOW mode
Priority for airflow is given to the front seats,
and the airflow and air conditioning for the
rear seats is effe ctively controlled.
A
B
C
D
E
F
A
B
C
D
E
F

3376-1. Maintenance and care
LEXUS NX300h Owners Manual_USA_M78578_en
6
Maintenance and care
Clean the air intake vents by the follow-
ing procedures to prevent dust from
accumulating in them, or to prevent
them from clogging.
There are air intake vents on the both sides
of the seats.
■Cleaning the air intake vents
1 Remove the dust from the vents
with a vacuum cleaner etc.
Clean the vents of the both sides.
2Start the hybrid system and check
that the warning message on the multi-information display disap-
pears.
It may take about 20 minutes before the
warning message disappears.
■Cleaning the air intake vents
●Dust on the air inta
ke vents may inter-
feres cooling of the hybrid battery (trac-
tion battery) and results in poor fuel
consumption. Clean the air intake vents
periodically.
●If continuing to drive the vehicle with
“Maintenance required for Traction bat-
tery cooling parts See owner’s manual”
shown on the multi-information display,
the hybrid battery (traction battery) input
and output may be restricted, leading to a
reduction in hybrid battery (traction bat-
tery) output and a malfunction. It may
cause poor fuel consumption or a mal-
function. If the warning message is shown,
contact your Lexus dealer or clean the air
intake vents immediately.
●If the warning message on the multi-infor-
mation display does not disappear after
cleaning the air intake vents, have the
vehicle inspected by your Lexus dealer.
●Timing of cleaning air intake vents differs
depending on the use environment of the
vehicle.
NOTICE
■Cleaning the front side windows
Do not use any compound or abrasive
product (e.g., glass cleaner, detergent,
wax) to clean the wi ndows. It may dam-
age the coating.
Cleaning the air intake vents

3456-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
6
Maintenance and care
Tire inflation
pressure
( P.365)• Tire pressure gauge
• Compressed air source
Washer fluid
( P.353)
• Water or washer fluid
containing antifreeze
(for winter use)
• Funnel (used only for adding water or washer
fluid)
WARNING
The engine compartment contains many
mechanisms and fluids that may move
suddenly, become hot, or become elec-
trically energized. To avoid death or seri-
ous injury, observe the following
precautions.
■When working on the engine com-
partment
●Make sure that the “IGNITION ON”
on the multi-information display and
the “READY” indicator are both off.
●Keep hands, clothi ng and tools away
from the moving fan and engine drive
belt.
●Be careful not to touch the engine,
power control unit, radiator, exhaust
manifold, etc. right after driving as they
may be hot. Oil and other fluids may
also be hot.
●Do not leave anything that may burn
easily, such as paper and rags, in the
engine compartment.
●Do not smoke, cause sparks or expose
an open flame to fuel. Fuel fumes are
flammable.
ItemsParts and tools■When working near the electric cool-
ing fans or radiator grille
Be sure the power switch is off.
With power switch in ON mode, the
electric cooling fans may automatically
start to run if the air conditioning is on
and/or the coolant temperature is high.
(  P.352)
■Safety glasses
Wear safety glasses to prevent flying or
falling material, fluid spray, etc. from get-
ting in your eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner filter
removed may cause excessive engine
wear due to dirt in the air.

3486-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
Fuse box (P.371)
Engine coolant reservoir ( P.351)
Engine oil filler cap ( P.350)
Power control unit coolant reservoir ( P.352)
Brake fluid reservoir ( P.353)
Radiator ( P.352)
Condenser ( P.352)
Electric cooling fans
Engine oil level dipstick ( P.349)
Washer fluid tank ( P.353)
■12-volt battery
 P.354
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J

3526-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
■Power control unit coolant reser-
voir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
■Coolant selection
Only use “Toyota Super Long Life Coolant”
or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite,
and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mix-
ture of 50% coolant and 50% deionized
water.
(Minimum temperature: -31°F [-35°C])
Canada:
“Toyota Super Long Life Coolant” is a mix-
ture of 55% coolant and 45% deionized
water.
(Minimum temperature: -44°F [-42°C])
For more details about coolant, contact
your Lexus dealer.
■If the coolant level drops within a short
time of replenishing
Visually check the radiator, hoses,
engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Lexus
dealer test the cap and check for leaks in
the cooling system.
Check the radiator and condenser and
clear away any foreign objects.
If either of the above parts is extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.
A
B
C
WARNING
■When the hybrid system is hot
Do not remove the en gine/power control
unit coolant reservoir caps.
The cooling system may be under pres-
sure and may spray hot coolant if the cap
is removed, causing serious injuries, such
as burns.
NOTICE
■When adding coolant
Coolant is neithe r plain water nor
straight antifreeze. The correct mixture
of water and antifreeze must be used to
provide proper lubrication, corrosion
protection and cooling. Be sure to read
the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to pre-
vent it from damaging parts or paint.
Checking the radiator and con-
denser
WARNING
■When the hybrid system is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.

3536-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
6
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
FMVSS No.116 DOT 3 or SAE J1703;
FMVSS No.116 DOT 4 or SAE J1704
brake fluid
Items
Clean funnel
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
If none of the washer do not work or
the “Windshield Washer Fluid Low” on
the multi-information display, the
washer tank may be empty. Add
washer fluid.
WARNING
■When the electric cooling fans are
operating
Do not touch the engine compartment.
With the power switch in ON mode, the
electric cooling fans may automatically
start to run if the air conditioning is on
and/or the coolant temperature is high.
Be sure the power switch is off when
working near the electric cooling fans or
radiator grille.
Checking and adding the brake
fluid
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.
If fluid gets on your hands or in your eyes,
flush the affected area with clean water
immediately.
If you still experience discomfort, see a
doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid leve l in the accumulator
is high.
If the reservoir needs frequent refilling,
there may be a serious problem.
Checking and adding the washer
fluid

4007-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
pedal has been depressed and the shift
lever is in N. Release the accelerator pedal
and shift the shift lever to D, S or R.
■If “Depress Brake When Vehicle Is
Stopped Hybrid Syst
em May Overheat”
is shown
Message is displayed when the accelerator
pedal is depressed to maintain the vehicle
position when stopped on a upward slope,
etc.
If this continues, th e hybrid system may
overheat.
Release the accelerator pedal and depress
the brake pedal.
■If a message that indicates the malfunc-
tion of front camera is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.209, 391)
●PCS (Pre-Collision System)
●LTA (Lane Tracing Assist) (if equipped)
●LDA (Lane Departure Alert with steering
control) (if equipped)
●Automatic High Beam
●RSA (Road Sign Assist) (if equipped)
●Dynamic radar cruise control with full-
speed range
■If “RSA malfunction Visit Your Dealer” is
shown
The system may be malfunctioning. Have
the vehicle inspected by your Lexus dealer.
■If “Radar Cruise Control Unavailable
See Owner’s Manual” is shown
The dynamic radar cruise control with full-
speed range system is suspended tempo-
rarily or until the problem shown in the mes-
sage is resolved. (causes and coping
methods: P.209)
■If “Radar Cruise Control Unavailable” is
shown
The dynamic radar cruise control with full-
speed range system cannot be used tempo-
rarily. Use the system when it becomes
available again.
■If “Oil Maintenance Required Soon” is
shown
Indicates that the engine oil is scheduled to
be changed. (The indicator will not work
properly unless the oil maintenance data
has been reset.)
Check the engine oil, and change if neces-
sary. After changing th e engine oil, the oil
change system should be reset. ( P.350)
■If “Oil Maintenance Required” is shown
Indicates that the engine oil should be
changed. (After the engine oil is changed
and the oil maintenance data has been
reset.)
Check and change the en gine oil, and oil fil-
ter by your Lexus dealer. After changing the
engine oil, the oil change system should be
reset. ( P.350)
■If “See Owner’s Manual” is shown
●If the following messages are shown, fol-
lowing the instruct ions, accordingly.
• “Engine Coolant Temp High” ( P.418)
●If the following messages are shown,
there may be a malfunction.
Immediately have the vehicle inspected
by your Lexus dealer.
• “Hybrid System Malfunction”
•“Check Engine”
• “Hybrid Battery System Malfunction”
• “Accelerator System Malfunction”
• “Braking Power Low”
• “Smart Access System Malfunction”
●If “Aux Battery Low” is shown
• When the display goes off after several
seconds
*
Maintain the hybrid system operation for
more than 15 minutes and charge the 12-
volt battery.
• When the display does not go off Start up the hybrid system using the pro-
cedures for “If the 12-volt battery is dis-
charged” ( P.414).
*: Displays for about 6 seconds
●If “Maintenance required for Traction bat-
tery cooling parts” is shown, the filters
may be clogged, the air intake vents may
be blocked, or there may be a gap in the
duct. Therefore, perform the following
correction procedure.
• If the air intake vents of the hybrid battery

4187-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
■“Engine Coolant Temp High” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the hybrid system.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the hybrid system has cooled
down sufficiently, inspect the hoses
WARNING
●Do not allow children near the 12-volt
battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at
your Lexus dealer as soon as possible.
If the 12-volt battery is deteriorating, con-
tinued use may cause the 12-volt battery
to emit a malodorous gas, which may be
detrimental to the health of passengers.
■When exchanging the 12-volt battery
After exchanging, securely attach the
exhaust hose and exhaust hole plug to
the exhaust hole of the exchanged 12-
volt battery. If not properly installed,
gases (hydrogen) may leak into the vehi-
cle interior, and there is the possible dan-
ger of the gas igniting and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another ve hicle in an emer-
gency. It cannot be used to jump start
another vehicle.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The needle of the engine coolant
temperature gauge ( P.84)
enters the red zone, or a loss of
hybrid system power is experi-
enced. (For example, the vehicle
speed does not increase.)
 “Engine Coolant Temp High” or
“Hybrid System Overheated” is
shown on the multi-information
display.
 Steam comes out from under the
hood.
Correction procedures