engine overheat LEXUS NX300h 2020 Owners Manual

4TABLE OF CONTENTS
LEXUS NX300h Owners Manual_USA_M78530_en
Luggage compartment features........................................................... 306
5-5. Using the other interior features Other interior features ............... 310
Garage door opener.................. 320
Compass.......................................... 326
6-1. Maintenance and care Cleaning and protecting the vehi-cle exterior ................................... 330
Cleaning and protecting the vehi- cle interior .................................... 333
6-2. Maintenance Maintenance requirements ..... 337
General maintenance ................ 338
Emission inspection and mainte- nance (I/M) programs ............ 340
6-3. Do-it-yourself maintenance Do-it-yourself service precautions........................................................... 342
Hood.................................................. 344
Positioning a floor jack............... 344
Engine compartment.................. 346
12-volt battery................................ 352
Tires ................................................... 355
Tire inflation pressure ................. 363
Wheels.............................................. 365
Air conditioning filter..................367
Electronic key battery ................ 368
Checking and replacing fuses 370
Headlight aim................................. 372
Light bulbs ....................................... 3747-1. Essential information
Emergency flashers .................... 378
If your vehicle has to be stopped in an emergency ............................ 378
If the vehicle is trapped in rising water .............................................. 379
7-2. Steps to take in an emergency If your vehicle needs to be towed........................................................... 381
If you think something is wrong .......................................................... 384
If a warning light turns on or a warn- ing buzzer sounds..................... 386
If a warning messa ge is displayed
.......................................................... 396
If you have a flat tire .................... 400
If the hybrid syst em will not start
.......................................................... 407
If you lose your keys.................... 409
If the fuel filler door cannot be opened .......................................... 409
If the electronic key does not oper- ate properly .................................. 410
If the 12-volt battery is discharged ............................................................ 412
If your vehicle overheats ............ 416
If the vehicle becomes stuck .... 419
8-1. Specifications Maintenance data (fuel, oil level, etc.) .................................................. 422
Fuel information .

........................... 430
Tire information ............................ 432
6Maintenance and care
7When trouble arises
8Vehicle specifications

13Pictorial index
LEXUS NX300h Owners Manual_USA_M78530_en
Windshield wipers ....................................................................................... P.195, 200
Precautions against winter season ................... ..........................................................P.277
To prevent freezing (windshield wiper de-icer) .................................................. P.294
Precautions against car wash ....................................................................................... P.331
Fuel filler door ........................................................................................................ P.202
Refueling method ............................................................................................................. P. 202
Fuel type/fuel tank capacity ...... ................................................................................... P.423
Tires.......................................................................................................................... .P.355
Tire size/inflation pressure ............................ ............................................................... P.428
Winter tires/tire chain .....................................................................................................P.2 77
Checking/rotation/tire pressure warning system..............................................P.355
Coping with flat tires........................................................................................................P .400
Hood ..........................................................................................................................P.344
Opening ........................................................................................................................ ....... P.344
Engine compartment cover ......................................................................................... P.347
Engine oil ..................................................................................................................... ......... P.424
Coping with overheat .......................................................................................................P.416
Warning messages .......................................................................................................... P.396
Headlights .................................................................................................................P.18 9
Parking lights/daytime running lights...............................................................P.189
Fog lights.................................................................................................................... P .195
Cornering lights
*.................................................................................................................. P.191
Turn signal lights ......................................................................................................P.182
Tail lights .................................................................................................................... P.189
License plate lights .................................................................................................P.189
Back-up light
Shifting the shift lever to R ...............................................................................................P.1 79
Light bulbs of the exterior lights for driving
(Replacing method: P.374, Watts: P.429)
D
E
F
G
H
I
J
K
L
M
N

882-1. Instrument cluster
LEXUS NX300h Owners Manual_USA_M78530_enthe multi-information display.
(Customizable features: 
P.441)
Switches between odometer, trip
meter and maintenance required infor-
mation displays. When the trip meter is
displayed, pressing and holding the button will reset the trip meter.
The brightness of the instrument panel
lights can be adjusted.
1
Darker
2 Brighter
■Instrument panel brightness adjustment
The instrument panel brightness levels
when the tail lights are on and off can be
adjusted individually. However, when the
surroundings are bright (daytime, etc.),
turning on the tail lights will not change the
instrument panel brightness. At this time,
any adjustments made to the instrument
panel brightness levels will be applied to
both settings at once.
WARNING
■The information display at low tem-
peratures
Allow the interior of the vehicle to warm
up before using the liquid crystal infor-
mation display. At extremely low tem-
peratures, the in formation display
monitor may respond slowly, and display
changes may be delayed.
For example, there is a lag between the
driver’s shifting and the new gear number
appearing on the display. This lag could
cause the driver to downshift again,
causing rapid and excessive engine brak-
ing and possibly an accident resulting in
personal death or injury.
NOTICE
■To prevent damage to the engine and
its components
●When the tachometer is displayed, 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); or “Engine Cool-
ant Temp High” or “Hybrid System
Overheated” is shown on the multi-
information display. In this case, imme-
diately stop the vehicle in a safe place,
and check the engine or hybrid system
after it has cooled completely.
(  P.416)
Changing between the odome-
ter, trip meter and maintenance
required information
Changing the Instrument panel
light brightness

1584-1. Before driving
LEXUS NX300h Owners Manual_USA_M78530_en
WARNING
●Do not drive the vehicle over or stop
the vehicle near flammable materials.
The exhaust system and exhaust gases
can be extremely hot. These hot parts
may cause a fire if there is any flamma-
ble material nearby.
●During normal driving, do not turn off
the hybrid system. Turning the hybrid
system off while driving will not cause
loss of steering or braking control,
however, power assist to the steering
will be lost. This will make it more diffi-
cult to steer smoothly, so you should
pull over and stop the vehicle as soon
as it is safe to do so.
In the event of an emergency, such as if
it becomes impossible to stop the vehi-
cle in the normal way: P.378
●Use engine braking (downshift) to
maintain a safe speed when driving
down a steep hill.
Using the brakes continuously may
cause the brakes to overheat and lose
effectiveness. ( P.179)
●Do not adjust the positions of the
steering wheel, the seat, or the inside
or outside rear view mirrors while driv-
ing.
Doing so may result in a loss of vehicle
control.
●Always check that all passengers’
arms, heads or other parts of their
body are not outside the vehicle.
●Do not drive the vehicle off-road.
This is not an AWD vehicle designed
for off-road driving. Proceed with all
due caution if it becomes unavoidable
to drive off-road.
●Do not drive across a river or through
other bodies of water.
This may cause electric/electronic
components to shor t circuit, damage
the hybrid system or cause other seri-
ous damage to the vehicle.
●Do not drive in excess of the speed
limit. Even if the legal speed limit per-
mits it, do not drive over 85 mph (140
km/h) unless your vehicle has high-
speed capability tires.
Driving over 85 mph (140 km/h) may
result in tire failure, loss of control and
possible injury. Be sure to consult a tire
dealer to determine whether the tires
on your vehicle are high-speed capa-
bility tires or not befo re driving at such
speeds.
■When driving on slippery road sur-
faces
●Sudden braking, acceleration and
steering may cause tire slippage and
reduce your ability to control the vehi-
cle.
●Sudden acceleration, engine braking
due to shifting, or changes in engine
speed could cause the vehicle to skid.
●After driving through a puddle, lightly
depress the brake pedal to make sure
that the brakes are functioning prop-
erly. Wet brake pads may prevent the
brakes from functioning properly. If the
brakes on only one side are wet and
not functioning properly, steering con-
trol may be affected.
■When shifting the shift lever
●Do not let the vehicle roll backward
while the shift lever is in a driving posi-
tion, or roll forward while the shift lever
is in R.
Doing so may result in an accident or
damage to the vehicle.
●Do not shift the shif t lever to P while
the vehicle is moving.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.
●Do not shift the shift lever to R while
the vehicle is moving forward.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.

1594-1. Before driving
LEXUS NX300h Owners Manual_USA_M78530_en
4
Driving
WARNING
●Do not shift the shift lever to a driving
position while the vehicle is moving
backward.
Doing so can damage the transmission
and may result in a loss of vehicle con-
trol.
●Shifting the shift lever to N while the
vehicle is moving will disengage the
hybrid system.
Engine braking is not available when N
is selected.
●Be careful not to shift the shift lever
with the accelerator pedal depressed.
Shifting the shift lever to any position
other than P or N may lead to unex-
pected rapid acceleration of the vehi-
cle that may cause an accident and
result in death or serious injury.
■If you hear a squealing or scraping
noise (brake pad wear limit indica-
tors)
Have the brake pads checked and
replaced by your Lexus dealer as soon as
possible. Rotor damage may result if the
pads are not replaced when needed.
It is dangerous to drive the vehicle when
the wear limits of the brake pads and/or
those of the brake discs are exceeded.
■When the vehicle is stopped
●Do not depress the accelerator pedal
unnecessarily.
If the shift lever is in any position other
than P or N, the vehicle may acceler-
ate suddenly and unexpectedly, caus-
ing an accident.
●In order to prevent accidents due to
the vehicle rolling away, always keep
depressing the brake pedal while
stopped with the “READY” indicator is
illuminated, and apply the parking
brake as necessary.
●If the vehicle is stopped on an incline,
in order to prevent accidents caused
by the vehicle rolling forward or back-
ward, always depress the brake pedal
and securely apply the parking brake
as needed.
●Avoid revving or racing the engine.
Running the engine at high speed
while the vehicle is stopped may cause
the exhaust system to overheat, which
could result in a fire if combustible
material is nearby.
■When the vehicle is parked
●Do not leave glasses, cigarette lighters,
spray cans, or soft drink cans in the
vehicle when it is in the sun.
Doing so may result in the following:
• Gas may leak from a cigarette lighter or spray can, and may lead to a fire.
• The temperature inside the vehicle may cause the plastic lenses and plas-
tic material of glasses to deform or
crack.
• Soft drink cans may fracture, causing the contents to spray over the interior
of the vehicle, and may also cause a
short circuit in the vehicle’s electrical
components.
●Do not leave cigarette lighters in the
vehicle. If a cigare tte lighter is in a
place such as the glove box or on the
floor, it may be lit accidentally when
luggage is loaded or the seat is
adjusted, causing a fire.
●Do not attach adhesive discs to the
windshield or windows. Do not place
containers such as air fresheners on
the instrument panel or dashboard.
Adhesive discs or containers may act
as lenses, causing a fire in the vehicle.
●Do not leave a door or window open if
the curved glass is coated with a met-
allized film such as a silver-colored
one. Reflected sunlight may cause the
glass to act as a lens, causing a fire.

1724-1. Before driving
LEXUS NX300h Owners Manual_USA_M78530_en
do not put the transmission in D.
( P.179)
 Instability happens more frequently
when descending steep or long
downhill grades. Before descend-
ing, 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 the
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 engine
coolant temperature gauge indi-
cates overheating, immediately turn
off the air conditioning (if in use),
pull your vehicle off the road and
stop in a safe spot. ( P.416)
 Always place wheel blocks under
both the vehicle’s and the trailer’s
wheels when parking. Put the trans-
mission in P and apply the parking
brake. Avoid parking on a slope, but
if unavoidable, do so only after per-
forming the following:
1 Apply the brakes and keep them
applied.
2 Have someone place wheel blocks
under both the vehicle’s and trailer’s
wheels. 3
When the wheel blocks are in
place, release the brakes slowly
until the blocks absorb the load.
4 Shift into P and apply the parking
brake.
5 Turn off the hybrid system.
 When restarting after parking on a
slope:
1 With the transmission in P, start the
hybrid system. Be sure to keep the
brake pedal depressed.
2 Shift into a forward gear. If revers-
ing, shift into R.
3 If the parking brake is in manual
mode, release the parking brake.
(P.184)
4 Release the brake pedal, and slowly
pull or back away from the wheel
blocks. Stop and apply the brakes.
5 Have someone retrieve the blocks.

3877-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78530_en
7
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.416)
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.

3987-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78530_enpedal 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 “Front Camera Unavailable” or “Front
Camera Unavailable See Owner’s
Manual” is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.208, 389)
●PCS (Pre-Collision System)
●LTA (Lane Tracing Assist)
●LDA (Lane Departure Alert with steering
control)
●Automatic High Beam
●RSA (Road Sign Assist)
●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.208)
■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.348)
■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.348)
■If “See Owner’s Manual” is shown
●If the following messages are shown, fol-
lowing the instruct ions, accordingly.
• “Engine Coolant Temp High” ( P.416)
●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.412).
*: 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

4167-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78530_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

4187-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78530_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.