Page 625 of 692

6258-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
■Run-flat tires (A “RFT” or “DSST” mark is molded on the sidewall)
Take your vehicle to the nearest
Lexus dealer or authorized tire
dealer as soon as possible if any tire
goes flat.
The vehicle can be driven for a maxi- mum of 300 km (186 miles) at a
speed below 60 km/h (37 mph)
after the tire pressure warning light comes on. ( P. 578)
■In some conditions (such as at high temperatures)
You cannot continue driving for up to 300 km (186 miles).
■For the detailed informat ion on run-flat tires
See the tire warranty booklet.
If you have a flat tire (vehicles with run-flat tires)
Your vehicle is not equipped with a sp are tire, but instead you can continue
driving the vehicle with run-flat tires even if any tire goes flat.In this case, slow
down and drive with extra caution.
NOTICE
■When replacing the tires
When removing or fitting the wheels, tires or the tire pressure warning valve and trans-
mitter, contact any authorized Lexus retailer or Lexus authorized repairer, or any reli- able repairer as the tire pressure warning valve and transmitter may be damaged if not
handled correctly.
■When driving over bumps
If a vehicle has a flat tire, the vehicle height will be lower than usual. Ensure that nothing
strikes the bottom of the vehicle.
■To avoid damage to the tire pressure warning valves and transmitters
When a tire is repaired with liquid sealants , the tire pressure warning valve and trans-
mitter may not operate properly. If a liqui d sealant is used, contact any authorized
Lexus retailer or Lexus authoriz ed repairer, or any reliable repairer or other qualified service shop as soon as possible. Make sure to replace the tire pressure warning valve
and transmitter when replacing the tire. ( P. 526)
Page 627 of 692

6278-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. (P. 631)
●One or both of the 12-volt battery terminals may be disconnected.
( P. 522)
Contact any authorized Lexus retailer or Lexus authorized repairer, or any reliable
repairer if the problem canno t be repaired, or if repair procedures are unknown.
When the hybrid system does not start, the following steps can be used as an
interim measure to start the hybrid system if the power switch is functioning nor-
mally.
Do not use this starting procedur e except in cases of emergency.
Set the parking brake.
Shift the shift lever to P.
Turn the power switch to ACCESSORY mode.
Press and hold the power switch for ab out 15 seconds while depressing the
brake pedal firmly.
Even if the hybrid system can be starte d using the above steps, the system may
be malfunctioning. Have the vehicle insp ected by any authorized Lexus retailer
or Lexus authorized repairer , or any reliable repairer.
The interior lights and headlights do not turn on, or the horn does not
sound.
Emergency start function
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3
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Page 628 of 692
6288-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
■Doors
Use the mechanical key ( P. 139)
in order to perform the following
operations:
Locks all the doors
Closes the windows and moon
roof (turn and hold)*
Unlocks all the doors
Opens the windows and moon roof (turn and hold)*
*: This setting must be customized at any authorized Lexus retailer or Lexus autho-
rized repairer, or an y reliable repairer.
■Trunk
Turn the mechanical key clockwise
to open.
If the electronic key does not operate properly
If communication between the electronic key and vehicle is interrupted ( P.
159) or the electronic key cannot be us ed because the battery is depleted, the
smart entry & start system and wireless remote control cannot be used. In
such cases, the doors and trunk can be opened and the hybrid system can be
started by following the procedure below.
Locking and unlocking the doors, unlocking the trunk and key linked
functions
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Page 629 of 692
6298-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
Ensure that the shift lever is in P and depress the brake pedal.
Touch the Lexus emblem side of the
electronic key to the power switch.
When the electronic key is detected, a buzzer sounds and th e power switch will
turn to ON mode.
When the smart entry & start system is deactivated in custom ization setting, the
power switch will turn to ACCESSORY
mode.
Firmly depress the brake pedal and check that is shown on the multi-
information display.
Press the power switch.
In the event that the hybrid system still cannot be started, contact any authorized
Lexus retailer or Lexus authorized repairer, or any reliable repairer.
Starting the hybrid system
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Page 631 of 692
6318-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
If you have a set of jumper (or booster) cables and a second vehicle with a 12-volt
battery, you can jump start your ve hicle by following the steps below.
Confirm that the electronic key is
being carried.
When connecting the jumper (or booster) cables, depending on the situa-
tion, the alarm may activate and doors
locked. (P. 94)
Open the hood ( P. 513) and fuse
box cover.
Remove the clips.
Push the tabs on either side to
detach the lock and lift the lid off
while pulling the lock plate.
If the 12-volt battery is discharged
The following procedures may be used to start the hybrid system if the 12-volt
battery is discharged.
You can also call any authorized Lexus retailer or Lexus authorized repairer,
or any reliable repairer.
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Page 633 of 692

6338-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
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 retailer or Lexus authorized repairer, or any
reliable repairer.
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 retailer or Lexus authorized repair er, or any reliable repairer 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 componen ts 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 w ill 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 repl acing the 12-volt battery
●In some cases, it may not be possible to unlock 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 retu rn to the mode it was in before the 12-volt battery was
discharged. Before disconnecting the 12-vol t 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.
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Page 634 of 692

6348-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
WARNING
■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 jump er cables to come into contact with each
other.
●Do not smoke, use matches, cigarette light ers or allow open flame near the 12-volt
battery.
■12-volt battery precautions
The 12-volt battery contains poisonous and co rrosive acidic electrolyte, while related
parts contain lead and lead compounds. Ob serve 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 retailer or Lexus autho-
rized repairer, or any reliable repairer as soon as possible.
If the 12-volt battery is deteriorating, co ntinued use may cause the 12-volt battery to emit a malodorous gas, which may be de trimental to the health of passengers.
■When replacing the 12-volt battery
P. 524
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
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