engine LEXUS NX300H 2019 Repair Manual

3967-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_M78287_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 and radiator core (radiator) for any
leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4
The 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
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
The needle of the engine coolant
temperature gauge ( P.79)
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
A
B
A
B
C

3977-2. Steps to take in an emergency
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When trouble arises
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.
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 (radiato r) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4 The 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.
A
B
A
B
C

3987-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_M78287_enWater can be used in an emergency if
coolant is unavailable.
6
After 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.
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.
●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 dama ge 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.

4038-1. Specifications
LEXUS NX300h Owners Manu-
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8
Vehicle specifications
This number is also stamped under the
right-hand front seat.■Engine number
The engine number is stamped on the
engine block as shown.
Front
Engine
Model2.5 L 4-cylinder (2AR-FXE)
Type4-cylinder in line, 4-cycle, gasoline
Bore and stroke3.54  3.86 in. (90.0  98.0 mm)
Displacement152.2 cu.in. (2494 cm3)
Valve clearance (engine cold)Automatic adjustment
Drive belt tensionAutomatic adjustment
Fuel
Fuel typeUnleaded gasoline only
Octane Rating87 (Research Octane Number 91) or higher
Fuel tank capacity (Reference)14.8 gal. (56 L, 12.3 Imp.gal.)
Electric motor (traction motor)
TypePermanent magnet synchronous motor
Maximum output105 kW
Maximum torque199 ft•lbf (270 N•m, 27.5 kgf•m)

4048-1. Specifications
LEXUS NX300h Owners Manu-
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Rear
■Oil capacity (Drain and refill [Reference*])
*: The engine oil capacity is a reference quantity to be used when changing the engine oil. Warm up the engine and turn off the hybrid system, wait more than 5 minutes, and check
the oil level on the dipstick.
■Engine oil selection
“Toyota Genuine Motor Oil” is used in
your Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil”
or equivalent to satisfy the following
grade and viscosity.
Oil grade: ILSAC GF-5 multigrade
engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good starting
in cold weather.
If SAE 0W-20 is not available, SAE 5W-20 oil may be used. However, it
must be replaced with SAE 0W-20 at
the next oil change.
Outside temperature
Oil viscosity (0W-20 is explained here
TypePermanent magnet synchronous motor
Maximum output50 kW
Maximum torque103 ft•lbf (139 N•m, 14.2 kgf•m)
Hybrid battery (traction battery)
TypeNickel-Metal hydride battery
Voltage7.2 V/module
Capacity6.5 Ah (3HR)
Quantity34 modules
Overall voltage244.8 V
Lubrication system
With filter4.6 qt. (4.4 L, 3.9 Imp.qt.)
Without filter4.2 qt. (4.0 L, 3.5 Imp.qt.)
A

4058-1. Specifications
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Vehicle specifications
as an example):
• The 0W in 0W-20 indicates the characteristic of the oil which allows
cold startability. Oils with a lower
value before the W allow for easier
starting of the engine in cold
weather.
• The 20 in 0W-20 indicates the vis- cosity characteristic of the oil when
the oil is at high temperature. An oil
with a higher viscosity (one with a
higher value) may be better suited if
the vehicle is operated at high
speeds, or under extreme load con-
ditions. How to read oil container label:
The International Lubricant Specifica-
tion Advisory Committee (ILSAC)
Certification Mark is added to some oil
containers to help you select the oil you
should use.
*: The coolant capacity is the quantity of reference.
If replacement is necessary, contact your Lexus dealer.
Cooling system
Capacity*
Gasoline
engine
Vehicles with towing package
7.7 qt. (7.3 L, 6.4 Imp.qt.)
Vehicles without towing package
7.1 qt. (6.7 L, 5.9 Imp.qt.)
Power con-
trol unit3.3 qt. (3.1 L, 2.7 Imp.qt.)
Coolant type
Use either of the following:
 “Toyota Super Long Life Coolant”
 Similar high-quality ethy lene glycol-based non-
silicate, non-amine, non-nitrite, and nonborate
coolant with long-life hy brid organic acid tech-
nology
Do not use plain water alone.

4108-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_M78287_en
■Gasoline quality
In very few cases, driveability problems may
be caused by the brand of gasoline you are
using. If driveability problems persist, try
changing the brand of gasoline. If this does
not correct the problem, consult your Lexus
dealer.
■Recommendation of the use of gasoline
containing detergent additives
●Lexus recommends the use of gasoline
that contains detergent additives to avoid
the build-up of engine deposits.
●All gasoline sold in the U.S.A. contains
minimum detergent additives to clean
and/or keep clean intake systems, per
EPA’s lowest additive s concentration pro-
gram.
●Lexus strongly recommends the use of
Top Tier Detergent Gasoline. For more
information on Top Tier Detergent Gaso-
line and a list of marketers, please go to
the official websit e www.toptiergas.com.
■Recommendation of the use of low
emissions gasoline
Gasolines containing oxygenates such as
ethers and ethanol, as well as reformulated
gasolines, are available in some cities.
These fuels are typically acceptable for use,
providing they meet other fuel require-
ments. Lexus recommends these fuels, since the
formulations allow for reduced vehicle
emissions.
■Non-recommendation of the use of
blended gasoline
●Use only gasoline containing up to 15%
ethanol.
DO NOT use any flex-fuel or gasoline
that could contain more than 15% etha-
nol, including from
any pump labeled
E30 (30% ethanol ), E50 (50% etha-
nol ), E85 (85% ethanol ) (which
are only some examples of fuel contain-
ing more than 15% ethanol).
●If you use gasohol in your vehicle, be sure
that it has an octane rating no lower than
87.
●Lexus does not recommend the use of
gasoline containing methanol.
■Non-recommendation of the use of gas-
oline containing MMT
Some gasoline contains an octane enhanc-
ing additive called MMT (Methylcyclopen-
tadienyl Manganese Tricarbonyl).
Lexus does not recommend the use of gas-
oline that contains MMT. If fuel containing
MMT is used, your emission control system
may be adversely affected.
The malfunction indicator lamp on the
instrument cluster may come on. If this hap-
pens, contact your Lexus dealer for service.
■If your engine knocks
●Consult your Lexus dealer.
●You may occasionally notice light knock-
ing for a short time wh ile accelerating or
driving uphill. This is normal and there is
no need for concern.
Fuel information
You must only use unleaded gaso-
line in your vehicle.
Select octane rating 87 (Research
Octane Number 91) or higher. Use
of unleaded gasoline with an octane
rating lower than 87 may result in
engine knocking. Persistent knock-
ing can lead to engine damage.
At minimum, the gasoline you use
should meet the specifications of
ASTM D4814 in the U.S.A.
A
BC

4118-1. Specifications
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Vehicle specifications
NOTICE
■Notice on fuel quality
●Do not use improper fuels. If improper
fuels are used, the engine will be dam-
aged.
●Do not use leaded gasoline.
Leaded gasoline can cause damage to
your vehicle’s three-way catalytic con-
verters causing the emission control sys-
tem to malfunction.
●Do not use gasohol other than the type
previously stated.
Other gasohol may cause fuel system
damage or vehicle performance prob-
lems.
●Using unleaded gasoline with an
octane number or rating lower than
the level previously stated will cause
persistent he avy knocking.
At worst, this will lead to engine dam-
age.
■Fuel-related poor driveability
If poor driveability (poor hot starting,
vaporization, engine knocking, etc.) is
encountered after using a different type
of fuel, discontinue the use of that type of
fuel.
■When refueling with gasohol
Take care not to spill gasohol. It can dam-
age your vehicle’s paint.

4168-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_M78287_en
Glossary of tire terminology
Tire related termMeaning
Cold tire
inflation
pressure
Tire pressure when the vehi-
cle has been parked for
three hours or more, or has
not been driven more than 1
mile or 1.5 km under that
condition
Maximum
inflation
pressureThe maximum cold inflated
pressure to which a tire may
be inflated, shown on the
sidewall of the tire
Recom-
mended
inflation
pressureCold tire inflation pressure
recommended by a manu-
facturer
Accessory
weight
The combined weight (in
excess of those standard
items which may be
replaced) of transmission,
power steering, power
brakes, power windows,
power seats, radio and
heater, to the extent that
these items are available as
factory-installed equipment
(whether installed or not)
Curb weight
The weight of a motor vehi-
cle with standard equip-
ment, including the
maximum capacity of fuel,
oil and coolant, and if so
equipped, air conditioning
and additional weight
optional engine
Maximum
loaded vehi-
cle weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options
weight
Normal
occupant
weight150 lb. (68 kg) times the
number of occupants speci-
fied in the second column of
Table 1
* that follows
Occupant
distribution
Distribution of occupants in
a vehicle as specified in the
third column of Table 1
*
below
Production
options
weight
The combined weight of
installed regular production
options weighing over 5 lb.
(2.3 kg) in excess of the
standard items which they
replace, not previously con-
sidered in curb weight or
accessory weight, including
heavy duty brakes, ride lev-
elers, roof rack, heavy duty
12-volt battery, and special
trim
Rim
A metal support for a tire or
a tire and tube assembly
upon which the tire beads
are seated
Rim diame-
ter
(Wheel
diameter)
Nominal diameter of the
bead seat
Rim size des-
ignationRim diameter and width
Tire related termMeaning

450Alphabetical Index
LEXUS NX300h Owners Manu-
al_USA_M78287_en
Emergency, in case of If a warning buzzer sounds .................. 367
If a warning light turns on ...................... 367
If a warning message is displayed..... 376
If the 12-volt battery is discharged .... 392
If the electronic key does not operate properly.......................................................389
If the fuel filler door cannot be opened .........................................................................389
If the hybrid system will not start ........ 387
If you have a flat tire .................................. 379
If you lose your keys................................ 388
If you think something is wrong .........365
If your vehicle becomes stuck.............399
If your vehicle has to be stopped in an
emergency ................................................360
If your vehicle needs to be towed ..... 362
If your vehicle overheats ........................396
Energy monitor ............................................... 93
Engine Accessory mode .........................................170
Compartment ............................................. 328
Engine switch................................................ 168
Hood................................................................ 326
How to start the hybrid system ........... 168
Identification number ...............................403
If your vehicle has to be stopped in an
emergency ................................................360
Ignition switch (power switch) ............. 168
Overheating.................................................396
Power switch ................................................ 168
Engine compartment cover .................... 329
Engine coolant Capacity .........................................................405
Checking .........................................................331
Preparing and checking before winter......................................................................... 256
Warning light ...............................................368
Engine coolant temperature gauge ........79 Engine oil
Capacity ........................................................ 404
Checking .......................................................329
Warning light .............................................. 368
Engine switch ................................................. 168
EPS (Electronic Power Steering) Function .......................................................... 249
Warning light .............................................. 369
EV drive mode................................................. 171
EV indicator ...................................................... 62
Event data recorder (E DR) ............................7
F
Flat tire ............................................................. 379
Tire pressure warning system .............339
Floor mats .......................................................... 24
Fluid Brake ................................................................407
Transmission................................................ 406
Washer ...........................................................333
Fog lights Replacing light bulbs ............................... 355
Switch................................................................188
Front passenger occupant classification system ................................................................ 41
Front passenger’s seat belt reminder light ............................................................................ 371
Front seat heaters.........................................274
Front seats ........................................................126 Adjustment ......................................................126
Cleaning .......................................................... 315
Correct driving posture ............................ 25
Driving position memory .........................132
Head restraints............................................. 135
Power easy access system .....................132
Seat heaters .................................................. 274
Seat position memory ...............................132