2021 LEXUS NX300h ECU

3957-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
7
When trouble arises
■Brake Override System/Drive-S tart Control warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■SRS warning light
This warning light system monitors the air-
bag sensor assembly, fr ont impact sensors,
side impact sensors (front door), side
impact sensors (rear), driver’s seat position
sensor, driver’s seat be lt buckle switch, front
passenger occupant cl assification system
(ECU and sensors), “AIR BAG ON” indi-
cator light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch,
driver’s seat belt pretensioner, front passen-
ger’s seat belt pretensioner and force lim-
iter, airbags, interconnecting wiring and
power sources. ( P.32)
■Front passenger detection sensor, seat
belt reminder and warning buzzer
●If luggage is placed on the front passen-
ger seat, the front passenger detection
sensor may cause th e warning light to
flash and the warning buzzer to sound even if a passenger is not sitting in the
seat.
●If a cushion is placed on the seat, the sen-
sor may not detect a passenger, and the
warning light may not operate properly.
■Electric power steering system warning
light (warning buzzer)
When the 12-volt battery charge becomes
insufficient of the voltage temporarily drops,
the electric power steering system warning
light may come on and the warning buzzer
may sound.
■If the malfunction indicator lamp comes
on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
Warning lightDetails/Actions
Brake Override System
Indicates that the accelerato r and brake pedals are being
depressed simultaneously, and the Brake Override System
is operating.
 Release the accelerator pedal and depress the brake
pedal.
Indicates a malfunction in the Brake Override System (with
warning buzzer)
 Have the vehicle inspected by your Lexus dealer
immediately.
Drive-Start Control
Indicates that the shift position was changed and Drive-
Start Control was operated wh ile depressing the accelera-
tor pedal. (with warning buzzer)
 Momentarily release th e accelerator pedal.
Indicates a malfunction in th e Drive-Start Control system
(with warning buzzer)
 Have the vehicle inspected by your Lexus dealer
immediately.

4047-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
4Use the hook to secure the deck
board as shown in the illustration.
5 Removing the jack.
1 Remove the rubber band.
2 Remove the cover and the jack.
When stowing the jack, close it by turning
the handle indicated by until it does not
move anymore, stow the jack and the
cover, and press on the jack to fix with the
rubber band.
1 Remove deck under tray.
2 Loosen the center fastener that
secures the spare tire.
1 Chock the tires.
A
Taking out the spare tire
WARNING
■When storing the spare tire
Be careful not to catch fingers or other
body parts between the spare tire and
the body of the vehicle.
Replacing a flat tire

4097-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
7
When trouble arises
One of the following may be the cause
of the problem:
The electronic key may not be func-
tioning properly. ( P.412)
 There may not be sufficient fuel in
the vehicle’s tank.
Refuel the vehicle. ( P.70)
 There may be a malfunction in the
immobilizer system. ( P.75)
 There may be a malfunction in the
steering lock system.
 The hybrid system may be malfunc-
tioning due to an electrical problem
such as electronic key battery
depletion or a blown fuse. However,
depending on the type of malfunc-
tion, an interim measure is available
to start the hybrid system. ( P.410)
WARNING
■After using the tools and jack
Before driving, make sure all the tools
and jack are securely in place in their
storage location to reduce the possibility
of personal injury during a collision or
sudden braking.
NOTICE
■Be careful when driving over bumps
with the compact spare tire installed
on the vehicle
The vehicle becomes lower when driving
with the compact spare tire compared to
when driving with standard tires. Be
careful when driving over uneven road
surfaces.
■Driving with tire chains and the com-
pact spare tire
Do not fit tire chains to the compact
spare tire.
Tire chains may damage the vehicle body
and adversely affect driving perfor-
mance.
■When replacing the tires
When removing or fitting the wheels,
tires or the tire pressure warning valve
and transmitter, contact your Lexus
dealer as the tire pr essure warning valve
and transmitter may be damaged if not
handled correctly.
If the hybrid system will not
start
Reasons for the hybrid system not
starting vary depending on the situ-
ation.
Check the following and perform
the appropriate procedure:
The hybrid system will not start
even though the correct starting
procedure is being followed.
(  P.174)

4177-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
7
When trouble arises
■When replacing the 12-volt battery
●Use a 12-volt battery that the case size is
same as the previous one (LN2), 20 hour
rate capacity (20HR) is equivalent
(60Ah) or greater, and performance rat-
ing (CCA) is equivalent (460A) or
greater.
• If the sizes differ, the 12-volt battery can-
not be properly secured.
• If the 20 hour rate capacity is low, even if the time period where the vehicle is not
used is a short time, the 12-volt battery
may discharge and hybrid system may
not be able to start.
●After exchanging, firmly attach the fol-
lowing items to the exhaust hole of the 12-
volt battery.
• Use the exhaust hose that was attached to the 12-volt battery before
exchanging and confirm that it is firmly
connected to the hole section of the vehi-
cle.
• Use the exhaust hole plug included
with the 12-volt battery exchanged or the
one installed on the battery prior to the
exchange. (Depending on the 12-volt
battery to be exchanged, the exhaust
hole may be plugged.)
For details, consult your Lexus dealer.
C
A
B
WARNING
■Avoiding 12-volt battery fires or
explosions
Observe the following precautions to
prevent accidentally igniting the flamma-
ble gas that may be emitted from the 12-
volt battery:
●Make sure each jumper cable is con-
nected to the correct terminal and that
it is not unintentionally in contact with
any other than the intended terminal.
●Do not allow the other end of the
jumper cable connected to the “+” ter-
minal to come into contact with any
other parts or meta l surfaces in the
area, such as brackets or unpainted
metal.
●Do not allow the + and - clamps of the
jumper cables to come into contact
with each other.
●Do not smoke, use matches, cigarette
lighters or allow open flame near the
12-volt battery.
■12-volt Battery precautions
The 12-volt battery contains poisonous
and corrosive acidic electrolyte, while
related parts contain lead and lead com-
pounds. Observe the following precau-
tions when handling the 12-volt battery:
●When working with the 12-volt battery,
always wear safety glasses and take
care not to allow any battery fluids
(acid) to come into contact with skin,
clothing or the vehicle body.
●Do not lean over the 12-volt battery.
●In the event that battery fluid comes
into contact with the skin or eyes,
immediately wash the affected area
with water and seek medical attention.
Place a wet sponge or cloth over the
affected area until medical attention
can be received.
●Always wash your ha nds after handling
the 12-volt battery support, terminals,
and other battery-related parts.

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

4418-1. Specifications
LEXUS NX300h Owners Manual_USA_M78578_en
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Vehicle specifications
*:Table 1  Occupant loading and distri-
bution for vehicle normal load for vari-
ous designated seating capacities
Pneumatic
tire
A mechanical device made
of rubber, chemicals, fabric
and steel or other materials,
that, when mounted on an
automotive wheel, provides
the traction and contains
the gas or fluid that sustains
the load
Radial ply
tire
A pneumatic tire in which
the ply cords that extend to
the beads are laid at sub-
stantially 90 degrees to the
centerline of the tread
Reinforced
tire
A tire designed to operate
at higher loads and at
higher inflation pressures
than the corresponding
standard tire
Section
width
The linear distance between
the exteriors of the sidewalls
of an inflated tire, excluding
elevations due to labeling,
decoration, or protective
bands
SidewallThat portion of a tire
between the tread and bead
Sidewall sep-
arationThe parting of the rubber
compound from the cord
material in the sidewall
Tire related termMeaning
Snow tire
A tire that attains a traction
index equal to or greater
than 110, compared to the
ASTM E-1136 Standard
Reference Test Tire, when
using the snow traction test
as described in ASTM F-
1805-00, Standard Test
Method for Single Wheel
Driving Traction in a
Straight Line on Snow-and
Ice-Covered Surfaces, and
which is marked with an
Alpine Symbol ( ) on at
least one sidewall
Test rim
The rim on which a tire is fit-
ted for testing, and may be
any rim listed as appropri-
ate for use with that tire
Tread
That portion of a tire that
comes into contact with the
road
Tread ribA tread section running cir-
cumferentially around a tire
Tread sepa-
rationPulling away of the tread
from the tire carcass
Treadwear
indicators
(TWI)
The projections within the
principal grooves designed
to give a visual indication of
the degrees of wear of the
tread
Wheel-hold-
ing fixtureThe fixture used to hold the
wheel and tire assembly
securely during testing
Tire related termMeaning

4458-2. Customization
LEXUS NX300h Owners Manual_USA_M78578_en
8
Vehicle specifications
■Smart access system with push-button start ( P.126)
■Wireless remote control ( P.107)
■Automatic light control system ( P.190)
FunctionDefault settingCustomized set-
ting
The doors that are unlocked
using the smart access sys-
tem with push-button start
can be selected
Driver’s doorAll the doorsO—OO
Smart access system with
push-button startOnOff——O—
Number of consecutive door
lock operations2 timesAs many as desired——O—
FunctionDefault settingCustomized set- ting
Wireless remote controlOnOff——O—
Unlocking operation
Driver’s door
unlocked in first step, all doors
unlocked in sec- ond step
All doors
unlocked in first
step
O—O—
Panic functionOnOff——O—
The function that validates the
switch of the wireless
remote control when locking
the door ( P.117)
When locking the
doorWhen unlocking
the door——O—
FunctionDefault settingCustomized set-ting
Light sensor sensitivityStandard-2 to 2O—O—
Adjust the time elapsed
before the headlights auto-
matically turn off
30 seconds
Off
O—O—60 seconds
90 seconds
ABCD
ABCD
ABCD

4569-1. For owners
LEXUS NX300h Owners Manual_USA_M78578_en
9-1.For owners
Déroulez la sangle diagonale de
telle sorte qu’elle passe bien sur
l’épaule, sans pour autant être en
contact avec le cou ou glisser de
l’épaule.
 Placez la sangle abdominale le plus
bas possible sur les hanches.
 Réglez la position du dossier de
siège. Asseyez-vous le dos le plus
droit possible et calez-vous bien
dans le siège.
 Ne pas vriller la ceinture de sécu-
rité.
Reporting safety defects for
U.S. owners
If you believe that your vehicle has
a defect which could cause a crash
or could cause injury or death, you
should immediately inform the
National Highway Traffic Safety
Administration (NHTSA) in addi-
tion to notifying the Lexus Division
of Toyota Motor Sa les, U.S.A., Inc.
(Toll-free: 1-800-25-LEXUS).
If NHTSA receives similar com-
plaints, it may open an investiga-
tion, and if it finds that a safety
defect exists in a group of vehicles,
it may order a recall and remedy
campaign. However, NHTSA can-
not become involved in individual
problems between you, your
dealer, or Lexus Division of Toyota
Motor Sales, U.S.A., Inc.
To contact NHTS A, you may call
the Vehicle Safety Hotline toll-free
at 1-888-327-4236 (TTY: 1-800-
424-9153); go to
http://www.safercar.gov; or write
to: Administrator, NHTSA, 1200
New Jersey Ave. SE., Washington,
DC 20590. You can also obtain
other information about motor
vehicle safety from
http://www.safercar.gov.
Seat belt instructions for
Canadian owners (in French)
The following is a French explana-
tion of seat belt instructions
extracted from the seat belt section
in this manual.
See the seat belt section for more
detailed seat belt instructions in
English.
Utilisation correcte des cein-
tures de sécurité