
4657-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53D56E)
CAUTION
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions 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 battery in
a garage or closed room where there is insufficient ventilation.
■How to recharge the 12-volt battery
Only perform a slow charge (4 A — 5 A). Th e 12-volt battery may explode if charged at
a quicker rate.
■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 fol-
low the procedure above if necessary.
●If you accidentally swallow electrolyte
Drink a large quantity of water or milk . Get emergency medical attention immedi-
ately.
■When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause gas (hydro-
gen) to enter the passenger compartment, causing a fire or explosion.
For replacement of the 12-volt battery, contact any authorized Lexus dealer or repairer,
or another duly qualified and equipped professional.
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.

5218-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
If a warning light turns on or a warning buzzer
sounds
Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, but then goes off, this does not necessar-
ily indicate a malfunction in the system. However, if this continues to occur,
have the vehicle inspected by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
Warning light and warning buzzer list
Warning lightWarning light/Details/Actions
Brake system warning light (warning buzzer)*1
Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning
→ Immediately stop the vehicle in a safe place and contact any
authorized Lexus dealer or repairer, or another duly qualified
and equipped professional. Continuing to drive the vehicle may
be dangerous.
Brake system warning light
Indicates a malfunction in:
• The regenerative braking system; or
• The electronically controlled brake system
→ Have the vehicle inspected by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional
immediately.
Charging system warning light
Indicates a malfunction in the vehicle’s charging system
→ Immediately stop the vehicle in a safe place and contact any
authorized Lexus dealer or repairer, or another duly qualified
and equipped professional.
Malfunction indicator lamp
Indicates a malfunction in:
• The hybrid system;
• The emission control system (if equipped);
• The electronic engine control system; or
• The electronic throttle control system
→ Have the vehicle inspected by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional
immediately.

5688-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
Maintain the engine speed of the second vehicle and start the hybrid system
of your vehicle by turning the power switch to ON mode.
Make sure the “READY” indicator comes on. If the indicator does not come
on, contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional.
Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the hybrid system starts, have the vehicle inspected at any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional as
soon as possible.
■Starting the hybrid system when the 12-volt battery is discharged
The hybrid system cannot be started by push-starting.
■To prevent 12-volt battery discharge
●Turn off the headlights and the audio system while the hybrid system is off.
●Turn off any unnecessary electrical components when the vehicle is running at a low
speed for an extended period, such as in heavy traffic.
■Charging the 12-volt battery
The electricity stored in the 12-volt battery will discharge gradually even when the vehicle
is not in use, due to natural discharge and the draining effects of certain electrical appli-
ances. If the vehicle is left for a long time, the 12-volt battery may discharge, and the
hybrid system may be unable to start. (The 12-volt battery recharges automatically while
the hybrid system is operating.)
■When recharging or replacing the 12-volt battery
●In some cases, it may not be possible to un lock the doors using the smart entry & start
system when the 12-volt battery is discharged. Use the wireless remote control or the
mechanical key to lock or unlock the doors.
●The hybrid system may not start on the first attempt after the 12-volt battery has
recharged but will start normally after the second attempt. This is not a malfunction.
●The power switch mode is memorized by the vehicle. When the 12-volt battery is
reconnected, the system will return to the mo de it was in before the 12-volt battery was
discharged. Before disconnecting the 12-volt battery, turn the power switch off.
If you are unsure what mode the power switch was in before the 12-volt battery dis-
charged, be especially careful when reconnecting the 12-volt battery.
7
8
9

5698-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
CAUTION
■Avoiding 12-volt battery fires or explosions
Observe the following precautions to prevent accidentally igniting the flammable gas
that may be emitted from the 12-volt battery:
●Make sure each jumper cable is connected to the correct terminal and that it is not
unintentionally in contact with any other than the intended terminal.
●Do not allow the other end of the jumper cable connected to the “+” terminal to come
into contact with any other parts or metal surfaces in the area, such as brackets or
unpainted metal.
●Do not allow the + and - clamps of the jumper cables to come into contact with each
other.
●Do not smoke, use matches, cigarette lighters or allow open flame near the 12-volt
battery.
■12-volt battery precautions
The 12-volt battery contains poisonous and corrosive acidic electrolyte, while related
parts contain lead and lead compounds. Observe the following precautions when han-
dling the 12-volt battery:
●When working with the 12-volt battery, always wear safety glasses and take care not
to allow any 12-volt battery fluids (acid) to come into contact with skin, clothing or the
vehicle body.
●Do not lean over the 12-volt battery.
●In the event that 12-volt battery fluid comes into contact with the skin or eyes, immedi-
ately wash the affected area with water and seek medical attention.
Place a wet sponge or cloth over the affected area until medical attention can be
received.
●Always wash your hands after handling the 12-volt battery support, terminals, and
other battery-related parts.
●Do not allow children near the 12-volt battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional as soon as possible.
If the 12-volt battery is deteriorating, continued use may cause the 12-volt battery to
emit a malodorous gas, which may be detrimental to the health of passengers.
■When replacing the 12-volt battery
→ P. 4 6 5

5849-1. Specifications
IS300h_EE(OM53D56E)
*: The fluid capacity is a reference quantity. If replacement is necessary, contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
Electrical system
12-volt battery
Open voltage at 20 °C
(68 °F):
12.5 V or higher: Fully charged
11.0 - 12.4 V: Half charged
10.9 V or lower: Discharged
(Check the voltage 20 minutes after the hybrid system
and all lights are turned off.)
Charging rates4 A — 5 A
Hybrid transmission
Fluid capacity*3.8 L (4.0 qt., 3.3 Imp. qt.)
Fluid typeTo y o t a G e n u i n e AT F W S
NOTICE
■Hybrid transmission fluid type
Using transmission fluid other than “Toyota Genuine ATF WS” may cause deterioration
in shift quality, locking up of your transmission accompanied by vibration, and ulti-
mately damage the hybrid transmission of your vehicle.

626Alphabetical index
IS300h_EE(OM53D56E)
Units .............................................................. 117
USB device ................................. 364, 406Connecting...........................................335
USB audio ............................................. 364
USB photo ........................................... 406
USB video ............................................. 364
USB port...................................................335
Vanity lights .............................................435 Vanity lights .......................................... 435
Wattage................................................. 588
Vanity mirrors ........................................435
VDIM (Vehicle Dynamics Integrated Management) .............. 297
Vehicle identification number ......... 579
Vehicle Stability Control (VSC) .................................................... 296
Ventilators (seat ventilators) ............ 424
VSC (Vehicle Stability Control)................................................. 296 Warning buzzers
Approach warning ........................... 259
Brake system ......................................... 521
Downshifting.........................................223
Driver’s and front passenger’s seat belt
reminder ............................................ 523
Lexus parking assist-sensor .........276
Open door ........................................... 523
Pre-crash braking ............................. 302
Rear passengers’ seat belt reminder ............................................. 523
Warning lights ........................................ 105
ABS ...........................................................522
Automatic headlight leveling system.................................................. 523
Brake system ......................................... 521
Charging system ................................. 521
Driver’s and front
passenger’s seat belt
reminder light................................... 523
Electric power steering system...................................................522
Low fuel level....................................... 523
Malfunction indicator lamp ............ 521
Master warning light ........................ 523
Open door ........................................... 523
Pre-crash safety system ..................522
Rear passengers’ seat belt reminder lights ................................ 523
Slip indicator .........................................522
SRS ............................................................522
Tire pressure........................................ 523
U
V
W