2019 LEXUS UX250H battery replacement

681-4. Hybrid system
battery) may overheat, leading to a
reduction in hybrid battery (traction
battery) output.
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.
■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.
NOTICE
■Hybrid battery (traction battery) air
intake vent
●Make sure not to block the air intake
vent with anything, such as a seat
cover, luggage or carpet. The hybrid
battery (traction battery) may over-
heat, leading to poor fuel economy.
●Clean the air intake vent regularly to
prevent the hybrid battery (traction
battery) from overheating.
●Do not get water or foreign materials
in the air intake vent as this may cause
a short circuit and damage the hybrid
battery (traction battery).
●A filter is installed to the air intake vent.
When the filter remains noticeably
dirty even after cleaning the air intake
vent, filter cleaning or replacement is
recommended. When cleaning or
replacing the filter, contact your Lexus
dealer.
Refer to P.365 for details on how to
clean the filter.
Emergency shut off system
Hybrid warning message

1053-1. Key information
3
Before driving
You can replace the battery by yourself
( P.368). However, as there is a danger
that the electronic key may be damaged, it
is recommended that replacement be car-
ried out by your Lexus dealer.
●To avoid serious deterioration, do not
leave the electronic key within 3 ft. (1 m)
of the following electr ical appliances that
produce a magnetic field:
• TVs
• Personal computers
• Cellular phones, cordless phones and battery chargers
• Recharging cellular phones or cordless phones
• Table lamps
• Induction cookers
■Replacing the battery
 P.368
■Confirmation of the registered key
number
The number of keys already registered to
the vehicle can be confirmed. Ask your
Lexus dealer for details.
■If “A New Key has been Registered
Contact Your Dealer for Details” is
shown on the multi-information display
This message will be displayed each time
the driver’s door is opened when the doors
are unlocked from the outside for approxi-
mately 10 days after a new electronic key
has been registered. If this message is dis-
played but you have not had a new elec-
tronic key registered, ask your Lexus dealer
to check if an unknown electronic key
(other than those in your possession) has
been registered.
NOTICE
■To prevent key damage
●Do not drop the keys, subject them to
strong shocks or bend them.
●Do not expose the keys to high tem-
peratures for long periods of time.
●Do not get the keys wet or wash them
in an ultrasonic washer, etc.
●Do not attach metallic or magnetic
materials to the keys or place the keys
close to such materials.
●Do not disassemble the keys.
●Do not attach a sticker or anything else
to the surface of the electronic key.
●Do not place the keys near objects that
produce magnetic fields, such as TVs,
audio systems and induction cookers,
or medical electrical equipment, such
as low-frequency therapy equipment.
■Carrying the electronic key on your
person
Carry the electronic key 3.9 in. (10 cm)
or more away from electric appliances
that are turned on. Radio waves emitted
from electric applianc es within 3.9 in. (10
cm) of the electronic key may interfere
with the key, causing the key to not func-
tion properly.
■In case of a smart access system with
push-button start malfunction or
other key-related problems
 P.403
■When an electronic key is lost
 P.402
■Handling the card key
●If the battery or card key terminals get
wet, the battery may corrode and the
card key may stop working.
If the key is dropped into water, or if
drinking water, etc., is spilled on the
key, immediately remove the battery
cover and wipe the battery and termi-
nals. (To remove the battery cover,
lightly grasp and pull it.) If the battery is
corroded, have your Lexus dealer
replace the battery.
●Do not crush the battery cover or use
a screwdriver to remove the battery
cover.
Forcibly removing the battery cover
may bend or damage the key.

2634-6. Driving tips
4
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.
 It is recommended that the vehicle is
fitted with four snow run-flat 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.
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
melt the ice. Wipe away the water
immediately to prevent it from
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 seri-
ous 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 LTA (Lane Tracing Assist).
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow
tires from Lexus dealers or legitimate tire
retailers.
This is because the removal and attach-
ment of snow tires affects the operation
of the tire pressure warning valves and
transmitters.
Before driving the vehicle

3286-2. Maintenance
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
After the required maintenance is per-
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 .
2
Press or of the meter control
switches, select “Vehicle Settings” and
then press “OK”.
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 serious injury or death.
■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 reproductive harm.
Avoid exposure and wash any affected
area immediately.
●12-volt battery posts, terminals and
related accessories contain lead and
lead compounds which are known to
cause brain damage. Wash your hands
after handling. ( P.342)
General maintenance
Scheduled maintenance

3446-3. Do-it-yourself maintenance
2Remove the right side deck board.
3 Remove the 12-volt battery cover.
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 Check the 12-volt battery condition by
indicator color.
Blue: Good condition
Red: Charging is necessary.
Have the vehicle inspected by your Lexus
dealer.
Clear: Replacement is necessary.
Have the 12-volt battery checked by your
Lexus dealer.
1Install the 12-volt battery cover.
Exterior
A
B
Checking 12-volt battery condi-
tion
Installing the 12-volt battery
cover
A
B
C

4107-2. Steps to take in an emergency
If the engine coolant temperature
gauge enters the red zone or
“Engine Coolant Temp High Stop in
a Safe Place See Owner’s Manual”
is shown on the multi-information
display
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
WARNING
■When replacing the 12-volt battery
●When the vent plug is close to the hold
down clamp, the battery fluid (acid)
may leak.
●For information regarding battery
replacement, contact your Lexus
dealer.
●After exchanging, securely attach the
elbow connected to the exhaust hose,
and exhaust hole plug to the exhaust
hole of the exchanged 12-volt battery.
If not properly installed, gases (hydro-
gen) may leak into the vehicle interior,
and there is the possible danger of the
gas igniting and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another vehicle in an emer-
gency. It cannot be used to jump start
another vehicle.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The engine coolant temperature
gauge ( P.78, 82) enters the
red zone, or a loss of hybrid sys-
tem power is experienced. (For
example, the vehicle speed does
not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” or “Hybrid system over-
heated Output power reduced” is
shown on the multi-information
display.
 Steam comes out from under the
hood.
Correction procedures

4208-1. Specifications
■Spark plug
■12-volt battery
*: The fluid capacity is a reference quantity.If replacement is necessary, contact your Lexus dealer.
Ignition system
MakeDENSO FC16HR-Q8
Gap0.031 in. (0.8 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system
Open voltage 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.)
Charging rates:
Quick charge
Slow charge
15 A max.
5 A max.
Hybrid transmission
Fluid capacity*4.0 qt. (3.8 L, 3.3 Imp.qt.)
Fluid typeToyota Genuine ATF WS
NOTICE
■Hybrid transmission fluid type
Using transmission fluid other than “Toyota Genuine ATF WS” may ultimately damage
the hybrid transmission of your vehicle.