2021 LEXUS NX300h battery replacement

731-4. Hybrid system
LEXUS NX300h Owners Manual_USA_M78578_en
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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-informa-
tion display, clean the air intake vents
(  P.337). If the message is still dis-
played 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

2594-5. Using the driving support systems
LEXUS NX300h Owners Manual_USA_M78578_en
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Driving
the side.
●Influence from the weather
• The area around the sensor is extremely hot or cold
• The wind is strong
• Ice, snow, dirt, etc., has adhered to the sensor (if removed, the system returns to
normal)
• Heavy rain or water strikes the vehicle
• In severe weather such as fog, snow or a
sand storm
●Influence from other sonic waves
• An ultrasonic wave source is nearby, such as the horn or clearance sonar of another
vehicle, a vehicle detector, a motorcycle
engine or the air brake of a large vehicle
• Electronic components (such as a backlit
license plate (especially fluorescent
types), fog lights, a fender pole or a wire-
less antenna) are inst alled near the sen-
sors
●Changes in the vehicle
• The vehicle is tilted a large amount
• The height of the vehicle has drastically changed due to the carried load (the
nose tilts up or down)
• The direction of the sensor has deviated due to a collision or other impact
■When “Parking Support Brake Unavail-
able” is displayed on the multi-informa-
tion display and the PKSB OFF indicator
flashes
●Ice, snow, dirt, etc., may have adhered to the sensor. If this occurs, remove the ice,
snow, dirt, etc., from the sensor to return
the system to normal.
Also, a warning message may be dis-
played at low temperatures due to ice
forming on the sensor, and the sensor
may not detect static objects. Once the
ice melts, the system will return to normal.
●If this message is shown even after
removing dirt from the sensor, or shown
when the sensor was not dirty to begin
with, have the vehicle inspected by your
Lexus dealer.
●System initialization may not have been
performed after remova
l and installation
of the 12-volt battery. Perform system ini-
tialization.
■When removing and installing the 12-
volt battery
The system needs to be initialized.
The system can be init ialized by driving the
vehicle straight ahead for 5 seconds or
more at a speed of approximately 22 mph
(35 km/h) or higher.
■When “Parking Support Brake Mal-
function Visit Your Dealer” is displayed
on the multi-information display, the
PKSB OFF indicator flashes and the
buzzer sounds
The system may not be operating properly.
Have the vehicle inspected by your Lexus
dealer.
WARNING
■In order for the system to operate
properly
Make sure to observe the following pre-
cautions regarding the sensors
(  P.251). Failure to observe these pre-
cautions may cause the sensors not to
operate properly, and may result in an
unexpected accident.
●Do not perform work such as modifi-
cation, disassembly or painting
●Only perform replacements using
genuine parts

2794-6. Driving tips
LEXUS NX300h Owners Manual_USA_M78578_en
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Driving
Use fluids that are appropriate to
the prevailing outside temperatures.
•Engine oil
• Engine/power control unit coolant
•Washer fluid
Have a service technician inspect
the condition of the 12-volt battery.
 Have the vehicle fitted with four
snow tires or purchase a set of tire
chains for the front tires
*.
Ensure that all tires are the same size and
brand, and that chains match the size of the
tires.
*: Tire chains cannot be mounted on the
225/60R18 tires.
Perform the following according to the
driving conditions:
 Do not try to forcibly open a window
or move a wiper that is frozen. Pour
warm water over the frozen area to
Winter driving tips
Carry out the necessary prepara-
tions and inspections before driving
the vehicle in winter. Always drive
the vehicle in a manner appropriate
to the prevailing weather condi-
tions.
Preparation for winter
WARNING
■Driving with snow tires
Observe the following precautions to
reduce the risk of accidents. Failure to do
so may result in a loss of vehicle control
and cause death or serious injury.
●Use tires of the specified size.
●Maintain the recommended level of air
pressure.
●Do not drive in excess of 75 mph (120
km/h), regardless of the type of snow
tires being used.
●Use snow tires on all, not just some
wheels.
■Driving with tire chains
Observe the following precautions to
reduce the risk of accidents. Failure to do
so may result in the vehicle being unable
to be driven safely, and may cause death
or serious injury.
●Do not drive in excess of the speed
limit specified for the tire chains being
used, or 30 mph (50 km/h), which-
ever is lower.
●Avoid driving on bumpy road surfaces
or over potholes.
●Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.
●Slow down sufficiently before entering
a curve to ensure that vehicle control is
maintained.
●Do not use LDA (Lane Departure
Alert with steering control) (if
equipped).
●Do not use LTA (Lane Tracing Assist)
(if equipped).
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow
tires from Lexus dealers or legitimate tire
retailers. This is be cause the removal and
attachment of snow tires affects the
operation of the tire pressure warning
valves and transmitters.
Before driving the vehicle

3396-2. Maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
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Maintenance and care
6-2.Maintenance
■Repair and replacement
It is recommended that genuine Lexus parts
be used for repairs to ensure performance
of each system. If non-Lexus parts are used
in replacement or if a repair shop other than
a Lexus dealer perfor ms repairs, confirm
the warranty coverage.
■Allow inspection and repairs to be per-
formed by a Lexus dealer
●Lexus technicians are well-trained spe-
cialists and are kept up to date with the
latest service information. They are well
informed about the operation of all sys-
tems on your vehicle.
●Keep a copy of the repa ir order. It proves
that the maintenance that has been per-
formed is under warra nty coverage. If any
problem should arise while your vehicle is
under warranty, your Lexus dealer will
promptly take care of it.
General maintenance should be per-
formed on a daily basis. This can be
done by yourself or by a Lexus dealer.
Scheduled maintenance should be
performed at specified intervals
according to the maintenance sched-
ule.
For details about ma intenance items and
schedules, refer to the “Warranty and Ser-
vice Guide”, “Owner’s Manual Supple-
ment” or “Scheduled Maintenance”.
■Resetting the message indicating main-
tenance is required (Except for Can-
ada)
After the required maintenance is pre-
formed according to the maintenance
schedule, please reset the message.
To reset the message, follow the procedures
described below:
1 Press or of the meter control
switches and select .
Maintenance requirements
To ensure safe and economical driv-
ing, day-to-day care and regular
maintenance are essential. It is the
owner’s responsibility to perform
regular checks. Lexus recommends
the following maintenance:
WARNING
■If your vehicle is not properly main-
tained
Improper maintenanc e could result in
serious damage to the vehicle and possi-
ble death or serious injury.
■Handling of the 12-volt battery
●Engine exhaust, some of its constitu-
ents, and a wide variety of automobile
components contain or emit chemicals
known to the State of California to
cause cancer and birth defects and
other reproductive harm. Work in a
well ventilated area.
●Oils, fuels and fluids contained in vehi-
cles as well as waste produced by
component wear contain or emit
chemicals known to the State of Cali-
fornia to cause cancer and birth
defects or other re productive harm.
Avoid exposure and wash any affected
area immediately.
●12-volt Battery post s, terminals and
related accessories contain lead and
lead compounds which are known to
cause brain damage. Wash your hands
after handling. ( P.354)
General maintenance
Scheduled maintenance

4288-1. Specifications
LEXUS NX300h Owners Manual_USA_M78578_en
*: The coolant capacity is the quantity of reference.
If replacement is necessary, contact your Lexus dealer.
■Spark plug
■12-volt battery
■Charging rates
*: The fluid capacity is the quantity of reference.If replacement is necessary, contact your Lexus dealer.
Ignition system
MakeDENSO FK16HR-A8
Gap0.03 in. (0.8 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system
Specific voltage reading
at 68°F (20°C):12.0 V or higher
If the voltage is lower than the standard value,
charge the battery.
(After charging the battery, turn on the high beam
headlights for 30 seconds with the power switch
off, and turn the headlights off.)
Quick charge
Slow charge15 A max.
5 A max.
Hybrid transmission
Fluid capacity*Front
4.0 qt. (3.8 L, 3.3 Imp.qt.)
Fluid typeToyota Genuine ATF WS