Page 458 of 628
4447-3. Do-it-yourself maintenance
IS300h_EE(OM53B95E)
Engine coolant reservoir
The coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir when the hybrid system is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to
the “FULL” line. (P. 555)
Power control unit coolant reservoir
The coolant level is satisfactory if it is between the “F” and “L” lines on
the reservoir when the hybrid system is cold.
Reservoir cap
“F” line
“L” line
If the level is on or below the “L”
line, add coolant up to the “F”
line.
(P. 555)
Coolant
1
2
3
1
2
3
Page 459 of 628

4457-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53B95E)
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% deion-
ized water. (Minimum temperature: -35C [-31F])
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 system.
CAUTION
When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or water
filler cap. (P. 558)
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 pro-
tection and cooling. 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.
Page 520 of 628

5068-2. Steps to take in an emergency
IS300h_EE(OM53B95E)
Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
Flat-looking tires or uneven tire wear
Engine coolant temperature gauge needle continually points higher
than normal.
Changes in exhaust sound
Excessive tire squeal when cornering
Strange noises related to the suspension system
Pinging or other noises related to the hybrid system
Engine missing, stumbling or running roughly
Appreciable loss of power
Vehicle pulls heavily to one side when braking
Vehicle pulls heavily to one side when driving on a level road
Loss of brake effectiveness, spongy feeling, pedal almost touches the
floor
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably
needs adjustment or repair. Contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 532 of 628

5188-2. Steps to take in an emergency
IS300h_EE(OM53B95E)
Indicates a malfunction in the EPS (Electric Power
Steering) system
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
Indicates that the vehicle is being driven at 5 km/h
(3 mph) or more with the parking brake still
engaged
A buzzer also sounds.
Release the parking brake.
Indicates a malfunction in:
• The SRS airbag system; or
• The seat belt pretensioner system
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
Indicates a malfunction in:
•The ABS; or
• The brake assist system
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
Indicates that the engine coolant temperature is too
high
A buzzer also sounds.
P. 5 5 6
(If equipped)
Indicates that the radar sensor is dirty or covered
with ice
A buzzer also sounds.
Clean the sensor.
Warning messageDetails/Actions
(Flashes)
Page 570 of 628

5568-2. Steps to take in an emergency
IS300h_EE(OM53B95E)
The needle of the engine coolant temperature gauge (P. 110) 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 sys-
tem, 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 (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact any
authorized Lexus dealer or
repairer, or another duly quali-
fied and equipped professional.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
Page 573 of 628

5598-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53B95E)
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” indica-
tor 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 muffler) 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. Add-
ing 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.).
When using coolant additives, use genuine Toyota products or equivalent.
Do not loosen the coolant reservoir caps
or water filler cap while the hybrid sys-
tem and radiator are hot.
High temperature steam or coolant could
spray out.
Page 582 of 628
567
9 9-1. Specifications
Vehicle specifications
IS300h_EE(OM53B95E)
Spark plug
Cooling system
Gasoline engine
Power control unit
Left-hand drive
vehiclesRight-hand drive
vehicles
Capacity8.2 L (8.7 qt.,
7.2 Imp. qt.)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-sili-
cate, 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.
Page 611 of 628

595Alphabetical index
IS300h_EE(OM53B95E)
Clock .........................................420
Coat hooks .................................424
Condenser .................................446
Console box ...............................414
Coolant ......................................444
Capacity ................................567
Checking ...............................444
Preparing and checking
before winter ......................311
Cooling system ..........................444
Engine overheating ...............556
Hybrid system overheating ...556
Cruise control
Cruise control .......................245
Dynamic radar cruise control .....
249
Cup holders ...............................415
Current fuel consumption ..........117
Curtain shield airbags .................43
Customizable features ...............576DAB (Digital Audio Broadcast)339
Daytime running light system . 227
Defogger
Front windshield .................. 404
Outside rear view mirrors .... 404
Rear window ........................ 404
Differential ............................... 569
Digital Audio Broadcast (DAB)339
Dimensions ............................... 562
Display
Drive information ................ 117
Dynamic radar cruise control ....
249
LDA (Lane Departure Alert) 265
Multi-information display.... 116
Warning message................. 514
Distance .................................... 118
Do-it-yourself maintenance ...... 435
Door courtesy lights
Location ............................... 411
Wattage ................................ 572
Door lock
Doors ................................... 136
Smart entry & start system .. 149
Wireless remote control ....... 130D