battery LEXUS NX300h 2020 Repair Manual

3406-2. Maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
The OBD system determines that a
problem exists somewhere in the emis-
sion control system. Your vehicle may
not pass the I/M test and may need to
be repaired. Contact your Lexus
dealer to service the vehicle.
When the 12-volt battery is discon-
nected or discharged
Readiness codes that are set during
ordinary driving are erased.
Also, depending on your driving
habits, the readiness codes may not
be completely set.
 When the fuel tank cap is loose
The malfunction indicator lamp
comes on indicating a temporary
malfunction and your vehicle may
not pass the I/M test.
Tires
• Is the tire inflation pres-
sure correct?
• The tires should not be damaged or excessively
worn.
• Have the tires been rotated according to the
maintenance schedule?
• The wheel nuts should not be loose.
Windshield
wipers/rear
window wiper
•The wiper blades should not show any signs of
cracking, splitting, wear,
contamination or defor-
mation.
•The wiper blades should clear the wind-
shield/rear window with-
out streaking or
skipping.
ItemsCheck pointsEmission inspection and
maintenance (I/M) pro-
grams
Some states have vehicle emission
inspection programs which include
OBD (On Board Diagnostics)
checks. The OBD system monitors
the operation of the emission con-
trol system.
If the malfunction indicator lamp
comes on
Your vehicle may not pass the
I/M test in the following situa-
tions:

3466-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
Fuse box (P.370)
Engine coolant reservoir ( P.349)
Engine oil filler cap ( P.348)
Power control unit coolant reservoir ( P.350)
Brake fluid reservoir ( P.351)
Radiator ( P.350)
Condenser ( P.350)
Electric cooling fans
Engine oil level dipstick ( P.347)
Washer fluid tank ( P.351)
■12-volt battery
 P.352
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J

3526-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
The 12-volt battery is located in the left-
hand side of luggage compartment.
■Before recharging
When recharging, the 12-volt battery pro-
duces hydrogen gas which is flammable
and explosive. Therefore, observe the fol-
lowing precautions before recharging:
●If recharging with the 12-volt battery
installed on the vehicle, be sure to discon-
nect the ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting the charger cables to the 12-volt
battery.
■After recharging/reconnecting the 12-
volt battery
●The hybrid system may not start. Follow
the procedure below to initialize the sys-
tem.
1 Shift the shift lever to P.
2 Open and close any of the doors.
3 Restart the hybrid system.
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the 12-volt battery. If this hap-
pens, use the wireless remote control or
the mechanical key to lock/unlock the
doors.
●Start the hybrid system with the power
switch in ACCESSORY mode. The
WARNING
■When adding washer fluid
Do not add washer fluid when the hybrid
system is hot or operating as washer fluid
contains alcohol and may catch fire if
spilled on the engine etc.
NOTICE
■Do not use any fluid other than
washer fluid
Do not use soapy water or engine anti-
freeze instead of washer fluid.
Doing so may cause streaking on the
vehicle’s painted surfaces, as well as
damaging the pump leading to problems
of the washer fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as neces-
sary.
Refer to the freezing temperatures listed
on the label of the washer fluid bottle.
12-volt battery
Location

3536-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
hybrid system may not start with the
power switch turned off. However, the
hybrid system will operate normally from
the second attempt.
●The power switch mode is recorded by
the vehicle. If the 12-volt battery is recon-
nected, the vehicle will return the power
switch mode to the status it was in before
the 12-volt battery was disconnected.
Make sure to turn off the power before
disconnect the 12- volt battery. Take extra
care when connecting the 12-volt battery
if the power switch mode prior to dis-
charge is unknown.
If the system will not st art even after multiple
attempts at all methods above, contact your
Lexus dealer.
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous
and corrosive sulfuric acid and may pro-
duce hydrogen gas which is flammable
and explosive. To reduce the risk of death
or serious injury, take the following pre-
cautions while working on or near the 12-
volt battery:
●Do not cause sparks by touching the
12-volt battery terminals with tools.
●Do not smoke or light a match near the
12-volt battery.
●Avoid contact with eyes, skin and
clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when
working near the 12-volt battery.
●Keep children away from the 12-volt
battery.
■Where to safely charge the 12-volt
battery
Always charge the 12-volt battery in an
open area. Do not charge the 12-volt bat-
tery in a garage or closed room where
there is insufficient ventilation.
■Emergency measures regarding
electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean water for at
least 15 minutes and get immediate
medical attention. If possible, continue
to apply water with a sponge or cloth
while traveling to the nearest medical
facility.
●If electrolyte gets on your skin
Wash the affected area thoroughly. If
you feel pain or burning, get medical
attention immediately.
●If electrolyte gets on your clothes
It can soak through clothing on to your
skin. Immediately take off the clothing
and follow the procedure above if nec-
essary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk.
Get emergency medical attention
immediately.
■When handling the 12-volt battery
 P.415
■When disconnecting the 12-volt bat-
tery
Do not disconnect the negative (-) termi-
nal on the body side as shown. The dis-
connected negative (-) terminal may
touch the positive (+) terminal, which
may cause a short and result in death or
serious injury.

3546-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
1Lift the deck board and attach the
hook. ( P.307)
2 Remove the left side deck board.
3 Remove the cover after removing
the chip.
Press
Pull out
Make sure that the 12-volt battery ter-
minals are not corroded and that there
are no loose connections, cracks, or loose clamps.
Terminals
Hold-down clamp
Insert the left side auxiliary box.
1 Push up center position
2 Insert
3 Press
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while
the hybrid system is operating. Also, be
sure all accessories are turned off.
Removing the 12-volt battery
maintenance cover
Exterior
A
B
Installing the 12-volt battery
maintenance cover
A
B

3686-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
■When the card key battery needs to be
replaced (if equipped)
The battery for the card key is available only
at Lexus dealers. Your Lexus dealer can
replace the battery for you.
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-but-
ton start and wireless remote control will
not function properly.
●The operationa l range will be reduced.
Prepare the following before replacing
the battery:
Flathead screwdriver
 Lithium battery CR2032
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus
dealer, local electrical appliance shops or
camera stores.
●Replace only with the same or equivalent
type recommended by the manufacturer.
●Dispose of used batteries according to
the local laws.
NOTICE
■When using the air conditioning sys-
tem
Make sure that a filter is always installed.
Using the air conditioning system without
a filter may cause damage to the system.
Electronic key battery
Replace the battery with a new one
if it is depleted.
Items to prepare

3696-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
1 Take out the mechanical key.
2 Remove the cover.
To prevent damage to the key, cover the tip
of the flathead screwdriver with a tape.
3Remove the depleted battery.
Insert a new battery with the “+” terminal
facing up.
Replacing the batteryWARNING
■Removed battery and other parts
These parts are small and if swallowed by
a child, they can cau se choking. Keep
away from children. Failure to do so
could result in death or serious injury.
NOTICE
■For normal operation after replacing
the battery
Observe the following precautions to
prevent accidents:
●Always work with dry hands.
Moisture may cause the battery to
rust.
●Do not touch or move any other com-
ponent inside the remote control.
●Do not bend either of the battery ter-
minals.

377
LEXUS NX300h Owners Manual_USA_M78530_en
7
7
When trouble arises
When trouble arises
7-1. Essential informationEmergency 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 warning buzzer sounds ....... 386
If a warning message is displayed ........................................................ 396
If you have a flat tire.................. 400
If the hybrid system 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 operate properly ..................... 410
If the 12-volt battery is discharged ......................................................... 412
If your vehicle overheats ......... 416
If the vehicle becomes stuck . 419

3787-1. Essential information
LEXUS NX300h Owners Manual_USA_M78530_en
7-1.Essential information
Press the switch.
All the turn signal lights will flash. To turn
them off, press the switch once again.
■Emergency flashers
If the emergency flashers are used for a
long time while the hybrid system is not
operating (while the “READY” indicator is
not illuminated), the 12-volt battery may dis-
charge.
1 Steadily step on the brake pedal
with both feet and firmly depress it.
Do not pump the brake pedal repeatedly
as this will increase the effort required to
slow the vehicle.
2Shift the shift lever to N.
If the shift lever is shifted to N
3 After slowing down, stop the vehi-
cle in a safe place by the road.
4 Stop the hybrid system.
If the shift lever cannot be shifted to
N
3 Keep depressing the brake pedal
with both feet to reduce vehicle
speed as much as possible.
4 To stop the hybrid system, press
and hold the power switch for 2
consecutive seconds or more, or
Emergency flashers
The emergency flashers are used to
warn other drivers when the vehicle
has to be stopped in the road due to
a breakdown, etc.
Operating instructions
If your vehicle has to be
stopped in an emergency
Only in an emergency, such as if it
becomes impossible to stop the
vehicle in the normal way, stop the
vehicle using the following proce-
dure:
Stopping the vehicle

3937-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78530_en
7
When trouble arises
■Brake Override System/Drive-S tart Control warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■SRS warning light
This warning light system monitors the air-
bag sensor assembly, fr ont impact sensors,
side impact sensors (front door), side
impact sensors (rear), driver’s seat position
sensor, driver’s seat be lt buckle switch, front
passenger occupant cl assification system
(ECU and sensors), “AIR BAG ON” indi-
cator light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch,
driver’s seat belt pretensioner, front passen-
ger’s seat belt pretensioner and force lim-
iter, airbags, interconnecting wiring and
power sources. ( P.32)
■Front passenger detection sensor, seat
belt reminder and warning buzzer
●If luggage is placed on the front passen-
ger seat, the front passenger detection
sensor may cause th e warning light to
flash and the warning buzzer to sound even if a passenger is not sitting in the
seat.
●If a cushion is placed on the seat, the sen-
sor may not detect a passenger, and the
warning light may not operate properly.
■Electric power steering system warning
light (warning buzzer)
When the 12-volt battery charge becomes
insufficient of the voltage temporarily drops,
the electric power steering system warning
light may come on and the warning buzzer
may sound.
■If the malfunction indicator lamp comes
on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
Warning lightDetails/Actions
Brake Override System
Indicates that the accelerato r and brake pedals are being
depressed simultaneously, and the Brake Override System
is operating.
 Release the accelerator pedal and depress the brake
pedal.
Indicates a malfunction in the Brake Override System (with
warning buzzer)
 Have the vehicle inspected by your Lexus dealer
immediately.
Drive-Start Control
Indicates that the shift position was changed and Drive-
Start Control was operated wh ile depressing the accelera-
tor pedal. (with warning buzzer)
 Momentarily release th e accelerator pedal.
Indicates a malfunction in th e Drive-Start Control system
(with warning buzzer)
 Have the vehicle inspected by your Lexus dealer
immediately.