Page 804 of 908
8047-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
■Stopping the engine
Shift the shift lever to P and press the “START STOP ENGINE” <“POWER”> switch
as you normally do when stopping the engine .
■Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the elec-
tronic key battery be replaced immediately when the battery is depleted. ( P. 7 1 0 )
■Changing “START STOP ENGINE” <“POWER”> switch modes
Release the brake pedal and press the “START STOP ENGINE” <“POWER”> switch
in step above.
The engine does not start and modes will be changed each time the
switch is pressed. ( P. 198, 205)
■When the electronic key does not work properly
●Make sure that the smart access system with push-button start has not been deac-
tivated in the customization setting. If it is off, turn the function on.
(Customizable features P. 8 5 2 )
●Check if battery-saving mode is set. If it is set, cancel the function. ( P. 1 2 9 )
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Page 805 of 908
805
ES350 300h_OM_OM33A01U_(U)
7
When trouble arises
7-2. Steps to take in an emergency
If the 12-volt battery is discharged (gasoline
vehicles)
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.
Open the hood ( P. 6 6 9 )
Connect the jumper cables according to the following procedure:
Connect a positive jumper cable cl amp to the positive (+) battery
terminal on your vehicle.
Connect the clamp on the other end of the positive cable to the pos-
itive (+) battery terminal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery terminal
on the second vehicle.
The following procedures may be used to start the engine if the 12-volt
battery is discharged.
You can also call your Lexus dealer or a qualified repair shop.
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Page 806 of 908

8067-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
Connect the clamp at the other end of the negative cable to a solid,
stationary, unpainted metallic point away from the 12-volt battery
and any moving parts, as shown in the illustration.
Start the engine of the second ve hicle. Increase the engine speed
slightly and maintain at that le vel for approximately 5 minutes to
recharge the 12-volt battery of your vehicle.
Open and close any of th e doors of your vehicle with the “START STOP
ENGINE” switch off.
Maintain the engine speed of the seco nd vehicle and start the engine of
your vehicle by turning the “START STOP ENGINE” switch to IGNI-
TION ON mode.
Once the vehicle’s engine has started , remove the jumper cables in the
exact reverse order from wh ich they were connected.
Once the engine starts, have the vehi cle inspected at your Lexus dealer as
soon as possible.
■Starting the engine when the 12-volt battery is discharged
The engine cannot be started by push-starting.
■To prevent 12-volt battery discharge
●Turn off the headlights and the audio system while the engine is off.
●Turn off any unnecessary electrical compon ents 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 will discharge gradually even when the
vehicle is not in use, due to natural discharge and the draining effects of certain elec-
trical appliances. If the vehicle is left for a long time, the 12-volt battery may dis-
charge, and the engine may be unable to start. (The 12-volt battery recharges
automatically during driving.)
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Page 807 of 908

8077-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
7
When trouble arises
■When recharging or replacing the 12-volt battery
●Make sure the key is not inside the vehicle when recharging or replacing the 12-volt
battery to prevent the doors from being locked with the key left inside the vehicle
when the alarm operates.
●In some cases, it may not be possible to unlock the doors using the smart access
system with push-button start when the 12-volt battery is discharged. Use the wire-
less remote control or the mechanical key to lock or unlock the doors.
●The engine may not start on the first atte mpt after the 12-volt battery has recharged
but will start normally after the second attempt. This is not a malfunction.
●The “START STOP ENGINE” switch mode is memorized by the vehicle. When the
12-volt battery is reconnected, the system will return to the mode it was in before
the 12-volt battery was discharged. Before disconnecting the 12-volt battery, turn
the “START STOP ENGINE” switch off.
If you are unsure what mode the “START STOP ENGINE” switch was in before the
12-volt battery discharged, be especially careful when reconnecting the 12-volt
battery.
CAUTION
■Avoiding 12-volt battery fires or explosions
Observe the following precautions to prev ent 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.
Page 808 of 908

8087-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
CAUTION
■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 precau-
tions when handling the 12-volt battery:
●When working with the 12-volt battery, always wear safety glasses and take care
not to allow any battery fluids (acid) to co me into contact with skin, clothing or the
vehicle body.
●Do not lean over the 12-volt battery.
●In the event that 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 th e battery support, terminals, and other
battery-related parts.
●Do not allow children near the 12-volt 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 810 of 908

8107-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
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 pos-
itive (+) 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 the negative cable to a solid,
stationary, unpainted metallic point away from the 12-volt battery
and any moving parts, as shown in the illustration.
Start the engine of the second ve hicle. Increase the engine speed
slightly and maintain at that le vel for approximately 5 minutes to
recharge the 12-volt battery of your vehicle.
Open and close any of the doors of your vehicle with the “POWER”
switch off.
Maintain the engine speed of the se cond vehicle and start the hybrid
system of your vehicle by turning the “POWER” switch to ON mode.
Make sure the “READY” indicator co mes on. If the indicator does not
come on, contact your Lexus dealer.
Once the hybrid system has started, remove the jumper cables in the
exact reverse order from wh ich they were connected.
Once the hybrid system starts, have the vehicle inspected at your Lexus
dealer as soon as possible.1
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Page 813 of 908

813
ES350 300h_OM_OM33A01U_(U)
7
When trouble arises
7-2. Steps to take in an emergency
If your vehicle overheats (gasoline vehicles)
Follow the correction procedure as described below.Stop the vehicle in a safe place and turn 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 radiator core (radia-
tor) for any leaks.
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” line on the reservoir.
Reservoir cap
“FULL”
“LOW”
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( P. 9 3 )
enters the red zone or a loss of engine power is experienced. (For
example, the vehicle speed does not increase.)
●Steam comes out from under the hood.
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Page 814 of 908

8147-2. Steps to take in an emergency
ES350 300h_OM_OM33A01U_(U)
Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
Start the engine and turn the air conditioning system on to check that
the radiator cooling fan operates and to chec k for coolant leaks from
the radiator or hoses.
The fan operates when the air conditioning system is turned on immediately after
a cold start. Confirm that the fan is 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 fan may not operate in freezing temperatures.)
If the fan is not operating:
Stop the engine immediately and contact your Lexus dealer.
If the fan is operating:
Have the vehicle inspected at the nearest Lexus dealer.
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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.
●Keep hands and clothing (especially a tie, a scarf or a muffler) away from the fan
and belts. Failure to do so may cause the hands or clothing to be caught, resulting
in serious injury.
●Do not loosen the radiator cap while the engine and radiator are hot.
High temperature steam or coolant could spray out.
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