2015 Lexus IS250 Battery replace

721-2. Theft deterrent system
IS350/250_U (OM53C50U)
■System maintenance
The vehicle has a maintenance-free type alarm system.
■Items to check before locking the vehicle
To prevent unexpected triggering of the alarm and vehicle theft, make sure of the follow-
ing:
●Nobody is in the vehicle.
●The windows and moon roof are closed before the alarm is set.
●No valuables or other personal items are left in the vehicle.
■Triggering of the alarm
The alarm may be triggered in the following situations:
(Stopping the alarm deactivates the alarm system.)
■Alarm-operated door lock
In the following situations, the doors are locked automatically to prevent intruders:
●The doors are unlocked manually without the mechanical key and the alarm is trig-
gered.
●While the alarm is operating, the doors are unlocked manually without the mechanical
key.
●A person inside the vehicle opens a door, the
trunk or hood, or unlocks the vehicle using a
inside lock button.
●The battery is recharged or replaced when the
vehicle is locked. (→P. 5 0 4 )
NOTICE
■To ensure the system operates correctly
Do not modify or remove the system. If modified or removed, the proper operation of
the system cannot be guaranteed.

1013-1. Key information
3
Operation of each component
IS350/250_U (OM53C50U)
■Electronic key battery depletion
●The standard battery life is 1 to 2 years. (The card key battery life is about a year and a
half.)
●If the battery becomes low, an alarm will sound in the cabin when the engine is stopped.
(→ P. 4 8 3 )
●As the electronic key always receives radio waves, the battery will become depleted
even if the electronic key is not used. The following symptoms indicate that the elec-
tronic key battery may be depleted. Replace the battery when necessary. ( →P. 4 3 9 )
• The smart access system with push-button start or the wireless remote control does not operate.
• The detection area becomes smaller.
• The LED indicator on the key surface does not turn on.
●To avoid serious deterioration, do not leave the electronic key within 3 ft. (1 m) of the
following electrical 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. 4 3 9
■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 wrong key is used
The key cylinder rotates freely to isolate inside mechanism.

1023-1. Key information
IS350/250_U (OM53C50U)
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 temperatures 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-fre-
quency 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 appliances within 3.9 in. (10 cm) of the
electronic key may interfere with the key, causing the key to not function properly.
■In case of a smart access system with push-button start malfunction or other key-
related problems
Take your vehicle with all the electronic keys provided with your vehicle, including the
card key, to your Lexus dealer.
■When an electronic key is lost
If the electronic key remains lost, the risk of vehicle theft increases significantly. Visit
your Lexus dealer immediately with all remaining electronic keys and the card key that
were provided with your vehicle.
■Handling the card key
●Do not apply excess force when inserting the mechanical key into the card key. Doing
so may damage the card key.
●If the battery or card key terminals get wet, the battery may corrode.
If the key is dropped into water, or if drin king water etc. is spilled on the key, immedi-
ately remove the battery cover and wipe the battery and terminals. (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.
●If the battery cover is frequently removed, the battery cover may become loose.
●When installing the battery, make sure to check the direction of the battery.
Installing the battery in the wrong direction may cause the battery to deplete rapidly.
●The surface of the card key may be damaged, or its coating may peel off in the follow-
ing situations:
• The card key is carried together with hard objects, such as coins and keys.
• The card key is scraped with a sharp object, such as the tip of a mechanical pencil.
• The surface of the card key is wiped with thinner or benzene.

1043-2. Opening, closing and locking the doors and trunk
IS350/250_U (OM53C50U)
■Operation signals
A buzzer sounds and the emergency flashers flash to indicate that the doors have been
locked/unlocked. (Locked: once; Unlocked: twice)
A buzzer sounds to indicate that the windows and moon roof are operating.
■Security feature
If a door is not opened within approximately 60 seconds after the vehicle is unlocked, the
security feature automatically locks the vehicle again.
■Welcome light illumination control
The front position, tail and license plate light s automatically turn on at night when the
doors are unlocked using the entry function or wireless remote control if the light switch
is in the “AUTO” position.
■When the door cannot be locked by the lock sensor on the upper part of the door han-
dle
■Door lock buzzer
If an attempt to lock the doors is made when a door is not fully closed, a buzzer sounds
continuously for 5 seconds. Fully close the door to stop the buzzer, and lock the vehicle
once more.
■Setting the alarm
Locking the doors will set the alarm system. ( →P. 7 1 )
■If the smart access system with push-button start or the wireless remote control does
not operate properly
Use the mechanical key to lock and unlock the doors. ( →P. 4 9 9 )
Replace the key battery with a new one if it is depleted. ( →P. 4 3 9 )
If the door will not lock even when the topside
sensor area is touched, try touching both the
topside and underside sensor areas at the same
time.

1113-2. Opening, closing and locking the doors and trunk
3
Operation of each component
IS350/250_U (OM53C50U)
■Trunk light
The trunk light turns on when the trunk is opened.
■Function to prevent the trunk being locked with the electronic key inside
●When all doors are locked, closing the trunk lid with the electronic key left inside the
trunk will sound an alarm.
In this case, the trunk lid can be opened pressing the trunk release button on the trunk
lid.
●If the spare electronic key is put in the tr unk with all the doors locked, the key confine-
ment prevention function is activated so the trunk can be opened. In order to prevent
theft, take all electronic keys with you when leaving the vehicle.
●If the electronic key is put in the trunk with all the doors locked, the key may not be
detected depending on the location of the key and the surrounding radio wave condi-
tions. In this case, the key confinement prevention function cannot be activated, causing
the doors to lock when the trunk is closed. Make sure to check where the key is before
closing the trunk.
●The key confinement prevention function cann ot be activated if any one of the doors is
unlocked. In this case, open the trunk using the trunk opener.
■Internal trunk release lever
■Using the mechanical key
The trunk can be also opened using the mechanical key. ( →P. 4 9 9 )
■If the smart access system with push-button start or the wireless remote control does
not operate properly
Use the mechanical key to unlock the trunk. ( →P. 4 9 9 )
Replace the key battery with a new one if it is depleted. ( →P. 4 3 9 )
■When leaving a key to the vehicle with a parking attendant
→P. 1 0 0
■Customization
The trunk unlocking operation can be changed. (Customizable features: →P. 5 3 7 )
The trunk lid can be open
ed by pulling the glow-
in-the-dark lever located on the inside of the
trunk lid to the side.
The lever will continue to glow for some time
after the trunk lid is closed.

4397-3. Do-it-yourself maintenance
7
Maintenance and care
IS350/250_U (OM53C50U)
●Flathead screwdriver
●Small flathead screwdriver
●Lithium battery CR2032
Take out the mechanical key.
Remove the cover.
To prevent damage to the key, wrap the
tip of the screwdriver with tape.
Remove the depleted battery.
Insert a new battery with the “+” termi-
nal facing up.
Electronic key battery
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
1
2
3

4407-3. Do-it-yourself maintenance
IS350/250_U (OM53C50U)
■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 local laws.
■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-button start and wireless remote control will not
function properly.
●The operational range will be reduced.
CAUTION
■Removed battery and other parts
These parts are small and if swallowed by a child, they can cause 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 component inside the remote control.
●Do not bend either of the battery terminals.

4698-2. Steps to take in an emergency
8
When trouble arises
IS350/250_U (OM53C50U)
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact sensors (front), side impact sensors (rear),
driver’s seat position sensor, driver’s seat belt buckle switch, front passenger occupant
classification system, “AIR BAG ON” indicat or light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch, seat belt pret ensioner assemblies, airbags,
interconnecting wiring and power sources. ( →P. 3 8 )
■Front passenger detection sensor, seat belt reminder and warning buzzer
If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passenger
is not sitting in the seat.
■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.
The light will go off after several driving trips.
If the light does not go off even after several trips, contact your Lexus dealer as soon as
possible.
■Electric power steering system warning light (warning buzzer)
When the 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.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not turn off the tire pressure warning light.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with the spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire.
■Conditions that the tire pressure warning system may not function properly
→ P. 4 2 8
■If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
engine switch is turned to IGNITION ON mode, have it checked by your Lexus dealer.
■Warning buzzer
In some cases, the buzzer may not be heard due to being in a noisy location or audio
sound.