Page 509 of 604

5097-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
GS F
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.
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 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.
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Page 510 of 604

5107-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
■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.
Page 511 of 604

5117-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
WARNING
■Avoiding battery fires or explosions
Observe the following precautions to preven t 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 jump er cables to come into 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 512 of 604
512
GS350_300_OM_OM30G96U_(U)7-2. Steps to take in an emergency
If your vehicle overheats
●The needle of the engine coolant temperature gauge (
P. 92, 98) 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 is coming 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, inspect the hoses and cooling
core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The following may indicate that your vehicle is overheating.
Correction procedures
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Page 513 of 604
5137-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
The coolant level is satisfactory if it is between the “FULL”/“F” and “LOW”/“L”
lines on the reservoir.
Engine coolant reservoir
“FULL”/“F”
“LOW”/“L”
Coolant inlet cap
Intercooler coolant reservoir4
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3
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GS350GS F
GS300
Page 514 of 604
5147-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(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.
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GS350GS F
GS300
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7
Page 515 of 604
5157-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
■When adding engine coolant (GS350/GS300)
Add coolant in accordance with the following procedure. Remove caps A and B.
Add engine coolant through the inlet of cap A up to the “[AR/GR] B” line, and then
install cap A.
Add engine coolant through the inlet of cap B until it is full, and then install cap B.
GS300 only: When inst alling cap B, apply coolant to the O-ring on the end of cap B.
Cap A
Cap B
“[AR/GR] B” line (Target fill line)
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3
GS350 GS300
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Page 516 of 604

5167-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(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.
●GS350: Do not loosen the coolant inlet cap
or the engine coolant reservoir cap while the
engine and radiator are hot.
High temperature steam or coolant could
spray out.
●GS F: Do not loosen the engine coolant res-
ervoir cap while the engine and radiator are
hot.
High temperature steam or coolant could
spray out.
●GS300: Do not loosen the coolant inlet cap,
the engine coolant rese rvoir cap or the inter-
cooler coolant reservoir cap while the engine
and radiator are hot.
High temperature steam or coolant could
spray out.