engine LEXUS NX300h 2018 Repair Manual

3837-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises 4 Lower the vehicle.
5 Firmly tighten each wheel nut two
or three times in the order shown in
the illustration.Tightening torque:
76 ft•lbf (103 N•m, 10.5 kgf•m)
6 Stow the flat tire, tire jack and all
tools. ■
The compact spare tire●
The compact spare tire is identified by the
label “TEMPORARY USE ONLY” on
the tire sidewall.
Use the compact spare tire temporarily,
and only in an emergency.
●
Make sure to check the tire inflation pres-
sure of the compact spare tire. ( → P.406)
■
After completing the tire change
The tire pressure warning system must be
reset. ( → P.341)
■
When using the compact spare tire
As the compact spare tire is not equipped
with a tire pressure warning valve and trans-
mitter, low inflation pressure of the spare
tire will not be indicated by the tire pressure warning system. Also, if you replace the
compact spare tire afte r the tire pressure
warning light comes on, the light remains
on. ■
When the compact spare tire is
equipped
The vehicle becomes lower when driving
with the compact spare tire compared to
when driving with standard tires. ■
If you have a flat front tire on a road cov-
ered with snow or ice
Install the compact spare tire on one of the
rear wheels of the vehicle. Perform the fol-
lowing steps and fit tire chains to the front
tires:
1 Replace a rear tire with the compact
spare tire.
2 Replace the flat front tire with the tire
removed from the rear of the vehicle.
3 Fit tire chains to the front tires.
WARNING■
When using the compact spare tire ●
Remember that the sp are tire provided
is specifically designed for use with
your vehicle. Do not use your spare
tire on another vehicle. ●
Do not use more than one spare tire
simultaneously.
●
Replace the spare tire with a standard
tire as soon as possible.
●
Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.

390 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U If you have a set of jumper (or booster)
cables and a second vehicle with a 12-
volt battery, you can jump start your
vehicle by following the steps below.
1 Confirm that the electronic key is
being carried.When connecting the jumper (or booster)
cables, depending on the situation, the
alarm may activate and the doors may lock.
( → P.72) 2 Open the hood ( → P.325) and fuse
box cover.
3 Open the exclusive jump starting
terminal cover.
4 Remove the engine cover.If the 12-volt battery is dis-
charged The following procedures may be
used to start the hybrid system if the
vehicle’s 12-volt battery is dis-
charged.
You can also call your Lexus dealer
or a qualified repair shop.
Restarting the hybrid system

3917-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises 5 Connect a positive jumper cable clamp to on your vehicle and connect the
clamp on the other end of the positive cab le to on the second vehicle. Then,
connect a negative cable clamp to on the second vehicle and connect the
clamp at the other end of the negative cable to .
Exclusive jump starting terminal (your vehicle)
Positive (+) battery terminal (second vehicle)
Negative (-) battery terminal (second vehicle)
Solid, stationary, unpainted metallic point away from the exclusive jump starting
terminal and any mo ving parts as shown in the illustration
6 Start the engine of the second vehicle. Increase the engine speed slightly and
maintain at that level for approximatel y 5 minutes to recharge the 12-volt bat-
tery of your vehicle.
7 Open and close any of the doors of yo ur vehicle with the power switch off.
8 Maintain the engine speed of the second vehicle and start the hybrid system of
your vehicle by turning the power switch to ON mode.
9 Make sure the “READY” indicator comes on. If the indicator light does not
come on, contact your Lexus dealer.
10 Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
11 Close the exclusive jump starting termin al cover, and reinstall the fuse box
cover to its original position.
Once the hybrid system starts, have the vehicle inspected at your Lexus dealer as
soon as possible. A
B
C
D
A
B
C
D

394 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 
“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

3957-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
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

396 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U Water 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.

4018-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_OM78212U 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.

FrontEngine Model 2.5 L 4-cylinder (2AR-FXE)
Type 4-cylinder in line, 4-cycle, gasoline
Bore and stroke 3.54 × 3.86 in. (90.0 × 98.0 mm)
Displacement 152.2 cu.in. (2494 cm 3
)
Valve clearance (engine cold) Automatic adjustment
Drive belt tension Automatic adjustment
Fuel Fuel type Unleaded gasoline only
Octane Rating 87 (Research Octane Number 91) or higher
Fuel tank capacity (Reference) 14.8 gal. (56 L, 12.3 Imp.gal.)
Electric motor (traction motor) Type Permanent magnet synchronous motor
Maximum output 105 kW
Maximum torque 199 ft•lbf (270 N•m, 27.5 kgf•m)

402 8-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_OM78212U 
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 Type Permanent magnet synchronous motor
Maximum output 50 kW
Maximum torque 103 ft•lbf (139 N•m, 14.2 kgf•m)
Hybrid battery (traction battery) Type Nickel-Metal hydride battery
Voltage 7.2 V/module
Capacity 6.5 Ah (3HR)
Quantity 34 modules
Overall voltage 244.8 V
Lubrication system With filter 4.6 qt. (4.4 L, 3.9 Imp.qt.)
Without filter 4.2 qt. (4.0 L, 3.5 Imp.qt.)
A

4038-1. Specifications
LEXUS NX300h Owners Manu-
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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 unit 3.3 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.

408 8-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_OM78212U ■
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. ■
Gasoline quality standards●
Automotive manufacturers in the U.S.A.,
Europe and Japan have developed a
specification for fuel quality called the
World-Wide Fuel Charter (WWFC),
which is expected to be applied world-
wide.●
The WWFC consists of four categories
that are based on required emission lev-
els. In the U.S., category 4 has been
adopted.
●
The WWFC improves air quality by low-
ering emissions in vehicle fleets, and
improves customer satisfaction through
better performance.
■
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 additives 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 website 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).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
B C