Page 589 of 692
5898-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
Indicates a malfunction in:
• The ABS; or • The brake assist system
A buzzer also sounds.
Have the vehicle inspected by any authorized Lexus retailer or Lexus authorized repairer, or any reliable
repairer.
Indicates that the engine coolant temperature is too high A buzzer also sounds.
P. 636
Indicates a malfunction in the vehicle’s charging system. Immediately stop the vehicle in a safe place and
contact any authorized Lexus retailer or Lexus
authorized repairer, or any reliable repairer. Con- tinuing to drive the vehicle may be dangerous.
Warning messageDetails/Actions
(F SPORT models)
Page 636 of 692

6368-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
●The needle of the engine coolant temperature gauge (P. 105) enters the
red zone or a loss of hybrid system po wer is experienced. (For example, the
vehicle speed does not increase.)
●“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” or
“Hybrid System Overheated Reduced Ou tput Power” 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 tu rn 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 retailer or Lexus authorized repairer, or any reli-
able repairer.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
Page 637 of 692

6378-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
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, tu rn 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 immediatel y and contact any authorized Lexus
retailer or Lexus auth orized repairer, or any reliable repairer.
If the fans are operating:
Have the vehicle inspected at the nearest authorized Lexus retailer or
Lexus authorized repairer, or any reliable repairer.
4
1
2
3
5
6
7
Page 639 of 692

6398-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
Start the hybrid system and check if “Hybrid System Overheated Reduced
Output Power” is shown on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact an y authorized Lexus retailer or Lexus
authorized repairer, or any reliable repairer.
If the message is not displayed:
Have the vehicle inspected at the nearest authorized Lexus retailer or
Lexus authorized repairer, or any reliable repairer.
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 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 be lt 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 c oolant reservoir caps or
water filler cap while th e hybrid system and
radiator are hot. High temperature steam or coolant could
spray out.
Page 678 of 692

678Alphabetical index
IS300h_EE(OM53D89E)
Engine coolant temperature
gauge....................................................... 105
Engine oil................................................... 516
Capacity ................................................. 647
Checking ................................................ 516
Preparing and checking
before winter ......................................361
Engine oil maintenance data............. 518
Engine switch .......................................... 219
EPS (Electric Power Steering)........ 352
Warning light ....................................... 576
ERA-GLONASS. ................................ 496
EV drive mode ....................................... 224
EV indicator ............................................... 79
First-aid kit storage belt .....................488
Flat tire
Vehicles with emergency
tire puncture repair kit ...................610
Vehicles with run-flat tires ............ 625
Floor mats ................................................... 34
Fluid
Brake .........................................................651
Hybrid
transmission......................................650
Washer..................................................... 521
Fog light .................................................... 244
Replacing light bulbs ....................... 562
Switch .......................................................244
Follow me home system .................... 238
Footwell light ........................................... 481
Wattage ................................................. 654
Front personal lights............................ 482
Wattage ................................................. 654
Front position lights ............................. 237
Light switch............................................237
Replacing light bulbs ....................... 562
F