engine coolant LEXUS NX300h 2021 User Guide

3516-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
6
Maintenance and care
2Press or of the meter control
switches, sele ct the “Vehicle Settings”
and then press .
3 Press or of the meter control
switches, select the “Oil Maintenance”
and then press and hold .
4 Select the “Yes” and push .
“The Data Has Been Reset” is displayed
on the multi-information display.
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
■Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
(  P.418)
WARNING
■Used engine oil
●Used engine oil contains potentially
harmful contaminants which may
cause skin disorders such as inflamma-
tion and skin cancer, so care should be
taken to avoid prolonged and
repeated contact. To remove used
engine oil from your skin, wash thor-
oughly with soap and water.
●Dispose of used oil and filters only in a
safe and acceptable manner. Do not
dispose of used oil and filters in house-
hold trash, in sewers or onto the
ground. Call your Lexus dealer, ser-
vice station or auto parts store for
information concerning recycling or
disposal.
●Do not leave used engine oil within the
reach of children.
NOTICE
■To prevent serious engine damage
Check the oil level on a regular basis.
■When replacing the engine oil
●Be careful not to spill engine oil on the
vehicle components.
●Avoid overfilling, or the engine could
be damaged.
●Check the oil level on the dipstick
every time you re fill the vehicle.
●Be sure the engine o il filler cap is prop-
erly tightened.
Checking the coolant
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B
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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
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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

3867-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
4Tighten down the towing eyelet
securely using a wheel nut wrench
or hard metal bar.
5 Securely attach cables or chains to
the towing eyelet.
Take care not to damage the vehicle body.
6Enter the vehicle being towed and
start the hybrid system.
If the hybrid system does not start, turn the
power switch to ON mode.
7Shift the shift lever to N and release
the parking brake.
Turn automatic mode off. ( P.184)
When the shift lever cannot be shifted:
 P.181
■While towing
If the hybrid system is off, the power assist
for the brakes and steering will not function,
making steering and braking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in luggage
compartment. ( P.402)
 Fluid leaks under the vehicle
(Water dripping from the air condi-
tioning after use is normal.)
 Flat-looking tires or uneven tire
wear
 Engine coolant temperature gauge
needle continually points higher
than normal
 Changes in exhaust sound
 Excessive tire squeal when corner-
ing
 Strange noises related to the sus-
pension system
 Pinging or other noises related to
the hybrid system
 Engine misfire or misses, stumbling
or running roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking
If you think something is
wrong
If you notice any of the following
symptoms, your vehicle probably
needs adjustment or repair. Con-
tact your Lexus dealer as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms

3897-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
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When trouble arises
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■Brake system warning light
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
Immediately stop the vehicl e in a safe place and con-
tact your Lexus dealer. Continuing to drive the vehicle
may be dangerous.
Warning lightDetails/Actions
Indicates that the engine is overheating
 Immediately stop the vehicle in a safe place. Continu-
ing to drive the vehicle may be dangerous.
Handling method ( P.418)
Warning lightDetails/Actions
(Yellow)
Indicates a malfunction in:
The regenerative braking system;
 The electronically controlled brake system; or
 The electric parking brake
 Have the vehicle inspected by your Lexus dealer
immediately.
Warning lightDetails/Actions
(U.S.A.)
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engine control system;
 The electronic throttle control system; or
 The emission control system
 Have the vehicle inspected by your Lexus dealer
immediately.

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

4197-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
7
When trouble arises
and radiator core (radiator) for any
leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
5 Add coolant if necessary.
Water can be used in an emergency if coolant is unavailable.
6
Start the hybrid system and turn the
air conditioning system on to check
that the radiator cooling fans oper-
ate and to check for coolant leaks
from the radiator or hoses.
The fans operate when the air conditioning
system is turned on immediately after a
cold start. Confirm that the fans are oper-
ating by checking the fan sound and air
flow. If it is difficult to check these, turn the
air conditioning system on and off repeat-
edly.
(The fans may not oper ate in freezing tem-
peratures.)
7 If the fans are not operating:
Stop the hybrid system immediately
and contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the
nearest Lexus dealer.
8 Check if “Engine Coolant Temp
High” is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact
your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the
nearest Lexus dealer.
A
B
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B
C

4207-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
■If “Hybrid System Overheated” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place.
2 Stop the hybrid system and care-
fully lift the hood.
3 After the hybrid system has cooled
down, inspect the hoses and radia-
tor core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line 5
Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
6After stopping the hybrid system
and waiting for 5 minutes or more,
start the hybrid system again and
check if “Hybrid System Over-
heated” is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact your
Lexus dealer.
If the message is not displayed:
The hybrid system temperature has
dropped and the vehicle may be driven
normally.
However, if the message appears again fre-
quently, contact your Lexus dealer.
A
B
A
B
C
WARNING
■To prevent an accident or injury when
inspecting under the hood of your
vehicle
Observe the following precautions.
Failure to do so may result in serious
injury such as burns.
●If steam is seen coming from under the
hood, do not open the hood until the
steam has subsided. The engine com-
partment may be very hot.

4217-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
7
When trouble arises
1Stop the hybrid system. Shift the
shift lever to P and set the parking
brake.
2 Remove the mud, snow or sand
from around the front wheels.
3 Place wood, stones or some other
material under the front wheels to
help provide traction.
4 Restart the hybrid system.
5 Shift the shift lever to D or R,
release the parking brake. Then,
while exercising caution, depress
the accelerator pedal.
■When it is difficult to free the vehicle
Press to turn off TRAC. ( P.273)
WARNING
●After the hybrid system has been
turned off, check that the “READY”
indicator is off. When the hybrid sys-
tem is operating, the gasoline engine
may automatically start, or the cooling
fan may suddenly operate even if the
gasoline engine stops. Do not touch or
approach rotating parts such as the
fan, which may lead to fingers or cloth-
ing (especially a tie, a scarf or a muf-
fler) getting caught, resulting in serious
injury.
●Do not loosen the coolant reservoir
cap while the hybrid system and radia-
tor are hot.
High temperature steam or coolant
could spray out.
NOTICE
■When adding engine/power control
unit coolant
Add coolant slowly after the hybrid sys-
tem has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too
quickly can cause damage to the hybrid
system.
■To prevent damage to the cooling sys-
tem
Observe the following precautions:
●Avoid contaminating the coolant with
foreign matter (such as sand or dust
etc.).
●Do not use any coolant additive.
If the vehicle becomes stuck
Carry out the following proce-
dures if the tires spin or the vehicle
becomes stuck in mud, dirt or snow:
Recovering procedure