Page 569 of 628

5698-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
CAUTION
■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 jumper cables to come into contact with each
other.
●Do not smoke, use matches, cigarette lighters or allow open flame near the 12-volt
battery.
■12-volt battery precautions
The 12-volt battery contains poisonous and corrosive acidic electrolyte, while related
parts contain lead and lead compounds. Observe 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 dealer or repairer, or
another duly qualified and equipped professional as soon as possible.
If the 12-volt battery is deteriorating, continued use may cause the 12-volt battery to
emit a malodorous gas, which may be detrimental to the health of passengers.
■When replacing the 12-volt battery
→ P. 4 6 5
Page 570 of 628
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.
Page 571 of 628

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
Page 572 of 628

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
Page 573 of 628
5738-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
The coolant level is satisfactory if
it is between the “F” and “L” lines
on the reservoir.Reservoir
“F”
“L”
Add coolant if necessary.
Water can be used in an emergency
if coolant is unavailable.
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.
4
1
2
3
5
6
Page 574 of 628

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.
Page 575 of 628
5758-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
Stop the hybrid system. Set the parking brake and shift the shift lever to P.
Remove the mud, snow or sand from around the rear wheels.
Place wood, stones or some other material under the rear wheels to help pro-
vide traction.
Restart the hybrid system.
Shift the shift lever to D or R and release the parking brake. Then, while exer-
cising caution, depress the accelerator pedal.
■When it is difficult to free the vehicle
If the vehicle becomes stuck
Carry out the following procedures if the tires spin or the vehicle becomes
stuck in mud, dirt or snow:
Press to turn off TRC.
1
2
3
4
5
Page 576 of 628
5768-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
CAUTION
■When attempting to free a stuck vehicle
If you choose to push the vehicle back and forth to free it, make sure the surrounding
area is clear to avoid striking other vehicles, objects or people. The vehicle may also
lunge forward or lunge back suddenly as it becomes free. Use extreme caution.
■When shifting the shift lever
Be careful not to shift the shift lever with the accelerator pedal depressed.
This may lead to unexpected rapid acceleration of the vehicle that may cause an acci-
dent resulting in death or serious injury.
NOTICE
■To avoid damaging the transmission and other components
●Avoid spinning the rear wheels and depressing the accelerator pedal more than nec-
essary.
●If the vehicle remains stuck even after these procedures are performed, the vehicle
may require towing to be freed.