Page 479 of 640

4797-3. Do-it-yourself maintenance
7
Maintenance and care
RC300h_EE(OM24740E)
■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 hybridorganic acid technology.
“Toyota Super Long Life Coolant” is a mixt ure of 50% coolant and 50% deionized water. (Minimum temperature: -35 C [-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 dulyqualified and equipped professional, test the cap and check for leaks in the cooling sys-
tem.
WARNING
■When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or water filler cap. ( P. 590)
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.
Page 536 of 640

5368-2. Steps to take in an emergency
RC300h_EE(OM24740E)
●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 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 fe eling, 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 an d equipped professional as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 547 of 640
5478-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
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 qualified 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 qualified and
equipped professional.
Indicates that the engine coolant temperature is too high
A buzzer also sounds. P. 587
(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 587 of 640

5878-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
●The hybrid system coolant temperature gauge (P. 115) is in the red zone or
a loss of hybrid system power is experi enced. (For example, the vehicle speed
does not increase.)
●“Engine Coolant High Temperature” or “Hybrid System Overheat Output
Power is limited” 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
or “Engine Coolant High Temperature” is shown on the multi-information
display
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, oranother duly qualified and
equipped professional.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
Page 590 of 640

5908-2. Steps to take in an emergency
RC300h_EE(OM24740E)
Start the hybrid system and check for the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If the message is not displayed:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
WARNING
■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 h ood, 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 ga soline engine may automatically start, or the cooling fan may suddenly operate even if the gasoline engine stops. Do not touchor 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.
6
●Do not loosen the coolant reservoir caps orradiator cap while the hybrid system and radi-
ator are hot. High temperature steam or coolant couldspray out.
Page 591 of 640
5918-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
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.
Page 601 of 640
601
9
9-1. Specifications
Vehicle specifications
RC300h_EE(OM24740E)
■Spark plug
Cooling system
Engine
Power control unit
Left-hand drive vehiclesRight-hand drive vehicles
Capacity8.3 L (8.8 qt., 7.3 Imp. qt.)2.1 L (2.2 qt., 1.8 Imp. qt.)2.3 L (2.4 qt., 2.0 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 no n-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 628 of 640

628Alphabetical index
RC300h_EE(OM24740E)
If your vehicle has to be
stopped in an emergency..........529
If your vehicle needs to
be towed............................................ 530
If your vehicle overheats ................587
Energy monitor....................................... 129
Engine....................................................... 598
ACCESSORY mode .......................216
Compartment...................................... 473
Engine switch.........................................215
Hood .......................................................... 471
How to start the hybrid system.....215
Identification number ....................... 597
If the hybrid system will not
start ........................................................ 576
Ignition switch (power switch) ......215
Overheating .........................................587
Power switch .........................................215
Engine coolant ....................................... 478
Capacity .................................................. 601
Checking ............................................ 478
Preparing and checking
before winter .................................... 337
Engine coolant temperature
gauge.........................................................115
Engine oil.................................................. 474
Capacity ................................................ 599
Checking ............................................... 474
Preparing and checking
before winter .................................... 337
Engine oil maintenance data............ 476
Engine switch .......................................... 215
EPS (Electric Power Steering)........304
Warning light ...................................... 538
EV drive mode ....................................... 220
EV indicator ............................................. 126
First-aid kit storage belt ..................... 452
Flat tire
Vehicles with emergency
tire puncture repair kit ................. 563
Floor mats ................................................... 34
Fluid
Brake ....................................................... 603
Hybrid transmission ......................... 602
Washer...................................................480
Fog lights .................................................. 239
Replacing light bulbs ....................... 525
Switch ...................................................... 239
Follow me home system .................... 233
Footwell light .......................................... 446
Wattage .................................................605
Front fog lights ....................................... 239
Replacing light bulbs ....................... 525
Switch ...................................................... 239
Front personal lights............................ 448
Front position lights ............................. 232
Light switch............................................232
Replacing light bulbs ....................... 525
Front seats .................................................178
Adjustment ............................................. 178
Cleaning ................................................ 464
Correct driving posture.................... 36
Driving position memory ................ 183
Head restraints .....................................186
Jam protection function ................... 179
Seat heaters.......................................... 445
Seat position memory .......................183
Seat ventilators ................................... 445
Front turn signal lights ........................ 229
Replacing light bulbs ...........520, 525
Turn signal lever..................................229
F