Page 575 of 660
5758-2. Steps to take in an emergency
8
When trouble arises
IS350 AWD/IS350/IS300 AWD/IS300_U
If you have a set of jumper (or booster) cables and a second vehicle with a 12-volt
battery, you can jump start your vehicle by following the steps below.
Confirm that the electronic key is
being carried.
When connecting the jumper (or
booster) cables, depe nding on the situa-
tion, the alarm may activate and doors
locked. (
P. 79)
Open the hood ( P. 470)
If the vehicle battery is discharged
The following procedures may be used to start the engine if the vehicle’s bat-
tery is discharged.
You can also call your Lexus deal er or a qualified repair shop.
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2
Page 576 of 660
5768-2. Steps to take in an emergency
IS350 AWD/IS350/IS300 AWD/IS300_U
Connect the jumper cables according to the following procedure:
IS350 AWD/IS350/IS300 AWD
IS300
Connect a positive jumper cable clamp to the positive (+) battery terminal
on your vehicle.
Connect the clamp on the other end of the positive cable to the positive (+)
battery terminal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery terminal on the
second vehicle.
Connect the clamp at the other end of th e negative cable to a solid, station-
ary, unpainted metallic po int away from the battery and any moving parts,
as shown in the illustration.
Start the engine of the second vehicle. Increase the engine speed slightly and
maintain at that level for approximatel y 5 minutes to recharge the battery of
your vehicle.
Open and close any of the doors of your vehicle with the engine switch off.
3
1
2
3
4
4
5
Page 577 of 660

5778-2. Steps to take in an emergency
8
When trouble arises
IS350 AWD/IS350/IS300 AWD/IS300_U
Maintain the engine speed of the second vehicle and start the engine of your
vehicle by turning the engine switch to IGNITION ON mode.
Once the vehicle’s engine has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the engine starts, have the vehicle inspected at your Lexus dealer as soon
as possible.
■Starting the engine when the battery is discharged
The engine cannot be started by push-starting.
■To prevent battery discharge
●Turn off the headlights and the audio system while the engine is off.
●Turn off any unnecessary electrical components when the vehicle is running at a low
speed for an extended period , such as in heavy traffic.
■Charging the battery
The electricity stored in the battery will disc harge gradually even when the vehicle is not
in use, due to natural discharge and the draini ng effects of certain electrical appliances. If
the vehicle is left for a long time, the battery may discharge, and the engine may be
unable to start. (The battery recharges automatically during driving.)
■When recharging or replacing the battery
●In some cases, it may not be possible to un lock the doors using the smart access system
with push-button start when the battery is discharged. Use the wireless remote control
or the mechanical key to lock or unlock the doors.
●The engine may not start on the first attempt after the battery has recharged but will
start normally after the second attempt. This is not a malfunction.
●The engine switch mode is memorized by the vehicle. When the battery is recon-
nected, the system will return to the mode it was in before the battery was discharged.
Before disconnecting the battery, turn the engine switch off.
If you are unsure what mode the engine switch was in before the battery discharged, be
especially careful when reconnecting the battery.
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Page 578 of 660

5788-2. Steps to take in an emergency
IS350 AWD/IS350/IS300 AWD/IS300_U
WARNING
■Avoiding battery fires or explosions
Observe the following precautions to prevent accidentally igniting the flammable gas
that may be emitted from the 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 cab le 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 in to contact with each
other.
●Do not smoke, use matches, cigarette lighters or allow open flame near the battery.
■Battery precautions
The battery contains poisonous and corrosive acidic electrolyte, while related parts
contain lead and lead compounds. Observ e the following precautions when handling
the battery:
●When working with the battery, always wear safety glasses and take care not to allow
any battery fluids (acid) to come into cont act with skin, clothing or the vehicle body.
●Do not lean over the battery.
●In the event that battery fluid comes into contact with the skin or eyes, immediately
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 afte r handling the battery support, terminals, and other bat-
tery-related parts.
●Do not allow childre n near the battery.
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure that they do not become entangled in the
cooling fans or engine drive belt.
Page 579 of 660
5798-2. Steps to take in an emergency
8
When trouble arises
IS350 AWD/IS350/IS300 AWD/IS300_U
●The needle of the engine coolant temperature gauge (P. 89) enters the red
zone or a loss of engine power is experienced. (For example, the vehicle
speed does not increase.)
●“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
shown on the multi-information display.
●Steam comes out from under the hood.
Stop the vehicle in a safe place and tu rn off the air conditioning system, and
then stop the engine.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the engine has cooled down
sufficiently, insp ect the hoses and
radiator core (radiator) for any
leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
Page 580 of 660
5808-2. Steps to take in an emergency
IS350 AWD/IS350/IS300 AWD/IS300_U
Engine coolant reservoir:
The coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir.
Reservoir cap
“FULL” line
“LOW” line
Intercooler coolant reservoir (IS300):
The coolant level is satisfactory if it is between the “F” and “L” lines on the reser-
voir.
Reservoir cap
“F” line
“L” line4
IS350 AWD/IS350/IS300 AWDIS300
1
2
3
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2
3
Page 581 of 660

5818-2. Steps to take in an emergency
8
When trouble arises
IS350 AWD/IS350/IS300 AWD/IS300_U
Add coolant if necessary.
Water can be used in an emergency if coolant is unavailable.
Start the engine and turn the air conditio ning system on to check that the radi-
ator 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 engine immediately an d contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
Check if “Engine Coolant Temp High St op in a Safe Place See Owner’s Man-
ual” is shown on the multi-information display.
If the message does not disappear:
Stop the engine and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
5
Engine (IS350 AWD/IS350/
IS300 AWD)Engine (IS300)
Intercooler (IS300)
6
7
8
Page 582 of 660

5828-2. Steps to take in an emergency
IS350 AWD/IS350/IS300 AWD/IS300_U
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.
●Keep hands and clothing (especially a tie, a scarf or a muffler) away from the fans and
belts. Failure to do so may cause the hands or clothing to be caught, resulting in seri-
ous injury.
NOTICE
■When adding engine coolant
Add coolant slowly after the engine has cooled down sufficiently. Adding cool coolant
to a hot engine too quickly can cause damage to the engine.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreig n matter (such as sand or dust etc.).
●Do not use any coolant additive.
●IS350 AWD/IS350/IS300 AWD: Do notloosen the coolant inlet cap or coolant reser-
voir cap while the engine and radiator are hot.
(The coolant inlet cap is located under the
engine cover.)
High temperature steam or coolant could
spray out.
●IS300: Do not loosen the coolant inlet cap,
coolant reservoir cap, or intercooler reser-
voir cap while the engine and radiator are hot.
High temperature steam or coolant could
spray out.