LEXUS NX300H 2019 Repair Manual

611-2. Hybrid system
LEXUS NX300h Owners Manu-
al_USA_M78287_en
1
For safety and security
1-2.Hybrid system
The illustration is an example for explanation and may differ from the actual item.
Gasoline engine
Front electric motor (traction motor)
Rear electric motor (traction motor)
■When stopped/during start off
The gasoline engine stops
* when the
vehicle is stopped. During start off, the
electric motor (traction motor) drives
the vehicle. At slow speeds or when
traveling down a gentle slope, the engine is stopped
* and the electric
motor (traction motor) is used.
When the shift lever is in N, the hybrid
battery (traction battery) is not being
charged. When the vehicle is stopped,
always put the shift lever to P.
Hybrid system features
Your vehicle is a hybrid vehicle. It has characteristics different from conven-
tional vehicles. Be sure you are closely fa miliar with the characteristics of your
vehicle, and operate it with care.
The hybrid system combines the use of a gasoline engine and an electric
motor (traction motor) according to driving conditions, improving fuel effi-
ciency and reducing exhaust emissions.
System components
A
B
C

621-2. Hybrid system
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Also, even in heavy traffic conditions,
drive the vehicle in D or S.
*: When the hybrid battery (traction bat-tery) requires charging or the engine is
warming up, etc., the gasoline engine will
not automatically stop. ( P.62)
■During normal driving
The gasoline engine is predominantly
used. The electric motor (traction
motor) charges the hybrid battery
(traction battery) as necessary.
■When accelerating sharply
When the accelerator pedal is
depressed heavily, the power of the
hybrid battery (traction battery) is
added to that of the gasoline engine via
the electric motor (traction motor).
■When braking (regenerative brak-
ing)
The wheels operate the electric motor
(traction motor) as a power generator,
and the hybrid battery (traction bat-
tery) is charged.
■Regenerative braking
In the following situations, kinetic energy is
converted to electric energy and decelera-
tion force can be obta ined in conjunction
with the recharging of the hybrid battery
(traction battery).
●The accelerator pedal is released while
driving with the shift lever in D or S.
●The brake pedal is depressed while driv-
ing with the shift lever in D or S.
■EV indicator
The EV indicator comes on when the vehi-
cle is driven using only the electric motor
(traction motor) or th e gasoline engine is
stopped.
■Conditions in which the gasoline engine
may not stop
The gasoline engine starts and stops auto-
matically. However, it may not stop auto-
matically in the following conditions
*:
●During gasoline engine warm-up
●During hybrid battery (traction battery)
charging
●When the temperature of the hybrid bat-
tery (traction battery) is high or low
●When the heater is switched on
*: Depending on the circumstances, the gasoline engine may also not stop auto-
matically in other situations.
■Charging the hybrid battery (traction
battery)
As the gasoline engine charges the hybrid
battery (traction battery), the battery does
not need to be charged from an outside
source. However, if the vehicle is left parked
for a long time the hybrid battery (traction
battery) will slowly discharge. For this rea-
son, be sure to drive the vehicle at least
once every few months for at least 30 min-
utes or 10 miles (16 km ). If the hybrid bat-
tery (traction battery) becomes fully
discharged and you are unable to start the
hybrid system, contact your Lexus dealer.
■Charging the 12-volt battery
 P.394
■After the 12-volt battery has discharged
or when the terminal has been removed
and installed during exchange, etc.
The gasoline engine may not stop even if
the vehicle is being driven by the hybrid bat-
tery (traction battery). If this continues for a
few days, contact your Lexus dealer.

631-2. Hybrid system
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For safety and security
■Sounds and vibrations specific to a
hybrid vehicle
There may be no engine sound or vibration
even though the vehicle is able to move with
the “READY” indicator is illuminated. For
safety, make sure to sh ift the shift lever to P
and apply the parking brake when parked.
The following sounds or vibrations may
occur when the hybrid system is operating
and are not a malfunction:
●Motor sounds may be heard from the
engine compartment.
●Sounds may be heard from the hybrid
battery (traction battery) behind the rear
seats when the hybrid system starts or
stops.
●Relay operating sounds such as a snap or
soft clank will be emitted from the hybrid
battery (traction battery), behind the rear
seats, when the hybrid system is started
or stopped.
●Sounds from the hybrid system may be
heard when the back door is open.
●Sounds may be heard from the transmis-
sion when the gasoline engine starts or
stops, when driving at low speeds, or
during idling.
●Engine sounds may be heard when
accelerating sharply.
●Sounds may be heard due to regenera-
tive braking when the brake pedal is
depressed or as the accelerator pedal is
released.
●Vibration may be felt when the gasoline
engine starts or stops.
●Cooling fan sounds may be heard from
the air intake vents under the rear seats.
■Maintenance, repair, recycling, and dis-
posal
Contact your Lexus dealer regarding main-
tenance, repair, recycling and disposal. Do
not dispose of the vehicle yourself.
■Customization
Settings (e.g. on/off operation of the EV
indicator) can be changed.
(Customizable features:  P.421)
When driving with the gasoline engine
stopped, a sound, which changes in
accordance with the driving speed, will
be played in order to warn people
nearby of the vehicle’s approach. The
sound will stop when the vehicle speed
exceeds approximately 15 mph (25
km/h).
■Vehicle proximity notification system
In the following cases, the vehicle proximity
notification system may be difficult for sur-
rounding people to hear.
●In very noisy areas
●In the wind or the rain
Also, as the vehicle proximity notification
system is installed on the front of the vehicle,
it may be more difficult to hear from the rear
of the vehicle compared to the front.
Vehicle proximity notification
system

641-2. Hybrid system
LEXUS NX300h Owners Manu-
al_USA_M78287_enThe illustration is an example for explanation and may differ from the actual item.
Warning label
Hybrid battery (traction battery)
Rear electric motor (traction motor)
Service plug
High voltage cables (orange)
Front electric motor (traction motor)
Power control unit
Air conditioning compressor
■Running out of fuel
When the vehicle has run out of fuel and the hybrid system cannot be started, refuel the
vehicle with at least enough gasoline to
make the low fuel level warning light
Hybrid system precautions
Take care when handling the hybrid sy
stem, as it is a high voltage system
(about 650 V at maximum) as well as contains parts that become extremely
hot when the hybrid system is operating. Obey the warning labels attached to
the vehicle.
System components
A
B
C
D
E
F
G
H

651-2. Hybrid system
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For safety and security
(  P.371) go off. If there is only a small
amount of fuel, the hybrid system may not
be able to start. (The standard amount of
fuel is about 2.7 gal. [10.1 L, 2.2 Imp.gal.],
when the vehicle is on a level surface. This
value may vary when the vehicle is on a
slope. Add extra fuel when the vehicle is
inclined.)
■Electromagnetic waves
●High voltage parts and cables on hybrid
vehicles incorporate electromagnetic
shielding, and ther efore emit approxi-
mately the same amount of electromag-
netic waves as conventional gasoline
powered vehicles or home electronic
appliances.
●Your vehicle may cause sound interfer-
ence in some third party-produced radio
parts.
■Hybrid battery (traction battery)
The hybrid battery (traction battery) has a
limited service life. The lifespan of the
hybrid battery (traction battery) can
change in accordance with driving style and
driving conditions.
WARNING
■High voltage precautions
This vehicle has high voltage DC and AC
systems as well as a 12-volt system. DC
and AC high voltage is very dangerous
and can cause severe burns and electric
shock that may result in death or serious
injury.
●Never touch, disassemble, remove or
replace the high voltage parts, cables
or their connectors.
●The hybrid system will become hot
after starting as the system uses high
voltage. Be careful of both the high
voltage and the high temperature, and
always obey the warning labels
attached to the vehicle.
●Never try to open the service plug
access hole located underneath the
rear seats. The service plug is used
only when the vehicle is serviced and is
subject to high voltage.
■Road accident cautions
Observe the following precautions to
reduce the risk of de ath or serious injury:
●Pull your vehicle off the road, shift the
shift lever to P, apply the parking brake,
and turn the hybrid system off.
●Do not touch the high voltage parts,
cables and connectors.
●If electric wires are exposed inside or
outside your vehicle, an electric shock
may occur. Never touch exposed elec-
tric wires.
●If a fluid leak occurs, do not touch the
fluid as it may be st rong alkaline elec-
trolyte from the hybrid battery (trac-
tion battery). If it comes into contact
with your skin or eyes, wash it off
immediately with a large amount of
water or, if possible, boric acid solu-
tion. Seek immediate medical atten-
tion.
●If a fire occurs in the hybrid vehicle,
leave the vehicle as soon as possible.
Never use a fire extinguisher that is not
meant for electric fires. Using even a
small amount of water may be danger-
ous.

661-2. Hybrid system
LEXUS NX300h Owners Manu-
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The cooling air intake and discharge
vents for the hybrid battery (traction
battery) are located under the rear
seats and between the rear seats and
deck board, respectively. If the air
intake vents are blocked, it could lead
to a reduction in hybrid battery (trac-
tion battery) output.
The hybrid battery (traction battery) out-
put will not be reduced, even if the space
between the upper part of the air dis-
charge vents on the back of the rear seat
and deck board is blocked with luggage,
etc.
WARNING
●If your vehicle needs to be towed, do
so with four wheels raised. If the
wheels connected to the electric
motor (traction motor) are on the
ground when towing, the motor may
continue to generate electricity. This
may cause a fire. ( P.362)
●Carefully inspect the ground under the
vehicle. If you find that liquid has
leaked onto the ground, the fuel sys-
tem may have been damaged. Leave
the vehicle as soon as possible.
■Hybrid battery (traction battery)
●Never resell, hand over or modify the
hybrid battery. To prevent accidents,
hybrid batteries that have been
removed from a disposed vehicle are
collected through Lexus dealers. Do
not dispose of the battery yourself.
Unless the battery is properly collected,
the following may occur, resulting in
death or serious injury:
• The hybrid battery may be illegally dis- posed of or dumped, and it is hazard-
ous to the environment or someone
may touch a high voltage part, result-
ing in an electric shock.
• The hybrid battery is intended to be used exclusively with your hybrid vehi-
cle. If the hybrid battery is used outside
of your vehicle or modified in any way,
accidents such as electric shock, heat
generation, smoke generation, an
explosion and electrolyte leakage may
occur.
When reselling or handing over your
vehicle, the possibility of an accident is
extremely high because the person
receiving the vehicle may not be aware
of these dangers.
●If your vehicle is disposed of without
the hybrid battery having been
removed, there is a danger of serious
electric shock if hi gh voltage parts,
cables and their connectors are
touched. In the event that your vehicle
must be disposed of, the hybrid battery
must be disposed of by your Lexus
dealer or a qualified service shop. If
the hybrid battery is not disposed of
properly, it may cause electric shock
that can result in death or serious
injury.
NOTICE
■Hybrid battery (traction battery)
Do not carry large amounts of water
such as water cooler bottles in the vehi-
cle. If water spills onto the hybrid battery
(traction battery), the battery may be
damaged.
Have the vehicle inspected by your
Lexus dealer.
Hybrid battery (traction bat-
tery) air intake and discharge
vents

671-2. Hybrid system
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For safety and security
Air intake vents
Air discharge vents When a certain level of impact is
detected by the impact sensor, the
emergency shut off system blocks the
high voltage current and stops the fuel
pump to minimize the risk of electrocu-
tion and fuel leakage. If the emergency
shut off system activates, your vehicle
will not restart. To restart the hybrid
system, contact your Lexus dealer.
A message is automatically displayed
when a malfunction occurs in the
hybrid system or an improper opera-
tion is attempted.
If a warning message is shown on the
multi-information display, read the
message and follow the instructions.
NOTICE
■Hybrid battery (traction battery) air
intake and discharge vents
●Do not place objects
that will block the
air intake vents. The hybrid battery
(traction battery) may have a reduc-
tion in hybrid battery (traction battery)
output as well as be damaged.
●Clean the air intake and discharge
vents regularly to prevent the hybrid
battery (traction battery) from over-
heating.
●Do not get water or foreign materials
in either the air intake and discharge
vents as this may cause a short circuit
and damage the hybrid battery (trac-
tion battery).
A
B
●If “Maintenance required for Traction
battery cooling parts. See owner’s
manual.” is shown on the multi-infor-
mation display, clean the air intake
vents ( P. 316). If the message is still
displayed after cleaning the air intake
vents, have the vehicle inspected by
your Lexus dealer.
●A filter is installed to the air intake vent.
When the filter re mains noticeably
dirty even after cleaning the air intake
vent, filter cleaning or replacement is
recommended. For information
regarding filter cleaning or replace-
ment, contact your Lexus dealer.
Emergency shut off system
Hybrid warning message

681-2. Hybrid system
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■If a warning light comes on, a warning
message is displayed, or the 12-volt bat-
tery is disconnected
The hybrid system may not start. In this
case, try to start the system again. If the
“READY” indicator does not come on, con-
tact your Lexus dealer.

691-3. Theft deterrent system
LEXUS NX300h Owners Manu-
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For safety and security
1-3.Theft deterrent system
The indicator light flashes after the
power switch has been turned off to
indicate that the system is operating.
The indicator light stops flashing after
the power switch has been turned to ACCESSORY or ON mode to indi-
cate that the system has been can-
celed.
■System maintenance
The vehicle has a maintenance-free type
immobilizer system.
■Conditions that may cause the system to
malfunction
●If the grip portion of the key is in contact
with a metallic object
●If the key is in close proximity to or touch-
ing a key registered to the security sys-
tem (key with a built-in transponder chip)
of another vehicle
■Certification for the immobilizer system
For vehicles sold in the U.S.A.
Immobilizer system
The vehicle’s keys have built-in tran-
sponder chips that prevent the
hybrid system from starting if a key
has not been previously registered
in the vehicle’s on-board computer.
Never leave the keys inside the
vehicle when you leave the vehicle.
This system is designed to help pre-
vent vehicle theft but does not guar-
antee absolute security against all
vehicle thefts.
Operating the system

701-3. Theft deterrent system
LEXUS NX300h Owners Manu-
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For vehicles sold in Canada
WARNING
■Certifications for the immobilizer
system
Changes or modifications not expressly
approved by the party responsible for
compliance could void the user’s author-
ity to operate the equipment.
NOTICE
■To ensure the system operates cor-
rectly
Do not modify or remove the system. If
modified or removed, the proper opera-
tion of the system cannot be guaranteed.