
4617-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53D56E)
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life hybrid
organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deionized water.
(Minimum temperature: -35 °C [-31 °F])
For more details about coolant, contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
■If the coolant level drops within a short time of replenishing
Visually check the radiators, hoses, engine/power control unit coolant reservoir caps,
drain cock and water pump.
If you cannot find a leak, have any authorized Lexus dealer or repairer, or another duly
qualified and equipped professional, test the cap and check for leaks in the cooling sys-
tem.
CAUTION
■When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or water filler cap.
( → P. 5 74 )
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water and
antifreeze must be used to provide proper lubrication, corrosion protection and cool-
ing. Be sure to read the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.

5358-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
Indicates a malfunction in the brake override systemA buzzer also sounds.
→ Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and
equipped professional.
Indicates that engine oil level is low
A buzzer also sounds.
→ Check the level of engine oil, and add if necessary.
Indicates that the hybrid system has overheated
This message may be displayed when driving under
severe operating conditions. (For example, when driv-
ing up a long steep hill.)
A buzzer also sounds.
→ Stop and check. ( →P. 5 7 1 )
Indicates a malfunction in:
• The automatic headlight leveling system; or
• The Automatic High Beam system (if equipped)
• The LED headlight system (if equipped)
A buzzer also sounds.
→ Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and
equipped professional.
Indicates that the accelerator and brake pedal are being
depressed simultaneously
→Release the accelerator or brake pedal.
Maintenance of the hybrid battery (traction battery)
cooling component is required
The filter may be clogged, the air intake vent may be
blocked or there may be a gap in the duct
→ Have maintenance performed on the hybrid battery
(traction battery) cooling component by any autho-
rized Lexus dealer or repairer, or another duly qual-
ified and equipped professional.
Indicates that the washer fluid level is low
→Add washer fluid.
Wa r n i n g m e s s a g eDetails/Actions
(Flashes)

5708-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure that they do not become entangled in the
cooling fans or belt.
■Exclusive jump starting terminal
The exclusive jump starting terminal is intended to charge the 12-volt battery on your
vehicle from another vehicle in an emergency. Do not use the exclusive jump starting
terminal to jump start another vehicle.

5718-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
●The needle of the engine coolant temperature gauge (→P. 109) enters the
red zone or a loss of hybrid system power is experienced. (For example, the
vehicle speed does not increase.)
●“Hybrid System Overheat” is shown on the multi-information display.
●Steam comes out from under the hood.
■If the needle of the engine coolant temperature gauge enters the red zone
Stop the vehicle in a safe place and turn off the air conditioning system, and
then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has
cooled down sufficiently, inspect
the hoses and radiator core (radi-
ator) for any leaks. Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact any autho-
rized Lexus dealer or repairer, or
another duly qualified and
equipped professional.
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
4
1
2
3

5728-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
Add coolant if necessary.
Water can be used in an emergency
if coolant is unavailable.
Start the hybrid system and turn the air conditioning system on to check
that the radiator cooling fans operate and to check for coolant leaks from
the radiator or hoses.
The fans operate when the air conditioning system is turned on immediately after a
cold start. Confirm that the fans are operating by checking the fan sound and air
flow. If it is difficult to check these, turn the air conditioning system on and off
repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the hybrid system immediately and contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
If the fans are operating:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
■If “Hybrid System Overheat” is shown on the multi-information displayStop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
After the hybrid system has
cooled down, inspect the hoses
and radiator core (radiator) for
any leaks.Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact any autho-
rized Lexus dealer or repairer, or
another duly qualified and
equipped professional.
5
6
7
1
2
3
1
2

5748-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
CAUTION
■When inspecting under the hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
●If steam is seen coming from under the hood, do not open the hood until the steam
has subsided. The engine compartment may be very hot.
●After the hybrid system has been turned off, check that the “READY” indicator is off.
When the hybrid system operating, the gasoline engine may automatically start, or
the cooling fan may suddenly operate even if the gasoline engine stops. Do not touch
or approach rotating parts such as the belt and fan, which may lead to fingers or
clothing (especially a tie, a scarf or a mu ffler) getting caught, resulting in serious
injury.
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently. Adding cool
coolant to a hot hybrid system too quickly can cause damage to the hybrid system.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use any coolant additive.
●Do not loosen the coolant reservoir caps or
water filler cap while the hybrid system and
radiator are hot.
High temperature steam or coolant could
spray out.

583
9
9-1. Specifications
Vehicle specifications
IS300h_EE(OM53D56E)
■Spark plug
Cooling system
Engine
Po w e r c o n t ro l u n i t
Left-hand drive
vehiclesRight-hand drive vehicles
Capacity8.2 L (8.7 qt.,
7. 2 I m p . q t . )2.0 L (2.1 qt.,
1.8 Imp. qt.)2.2 L (2.3 qt.,
1.9 Imp. qt.)
Coolant type
Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-silicate,non-amine, non-nitrite, and non-borate coolant with long-
life hybrid organic acid technology
Do not use plain water alone.
Ignition system
Make DENSO FK20HBR8
Gap 0.8 mm (0.031 in.)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.

611Alphabetical index
IS300h_EE(OM53D56E)
Child-protectors ................................... 140
Cleaning ........................................442, 446Aluminum wheels .............................. 443
Exterior.................................................... 442
Interior .....................................................446
Seat belts................................................ 447
Clock .........................................................435
Coat hooks ..............................................439
Condenser ............................................. 462
Console box ........................................... 429
Coolant .....................................................460 Capacity ................................................ 583
Checking .............................................. 460
Preparing and checking
before winter .................................... 322
Cooling system......................................460
Engine overheating ............................571
Hybrid system overheating ............571
Cruise control Cruise control .....................................250
Dynamic radar cruise control ..... 254
Cup holders ............................................430
Current fuel consumption....................116
Curtain shield airbags ........................... 43
Customizable features ....................... 592 DAB (Digital Audio Broadcast) ..... 352
Daytime running light system ......... 230
Defogger
Outside rear view mirrors .............. 418
Rear window..........................................418
Windshield ............................................. 418
Differential............................................... 585
Digital Audio Broadcast (DAB) ..... 352
Dimensions ............................................. 578
Display Drive information...................................116
Dynamic radar cruise control ..... 254
LDA (Lane Departure Alert) ........ 271
Multi-information display...................115
Warning message .............................527
Distance ...................................................... 117
Do-it-yourself maintenance ...............451
Door courtesy lights Location ................................................. 425
Wattage ................................................ 588
Door lock
Doors......................................................... 136
Smart entry & start system ............. 149
Wireless remote control .................130D