Page 813 of 918
8127-2. Steps to take in an emergency
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■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 9 )
■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 star t and modes will be changed each time the
switch is pressed. ( →P. 202, 209)
■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 6 2 )
●Check if battery-saving mode is set. If it is set, cancel the function. ( →P. 131)
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When trouble arises
7-2. Steps to take in an emergency
If the 12-volt battery is discharged (hybrid 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 trunk lid and remove the 12-volt battery cover.
(→ P. 6 9 8 )
In the event that the trunk opener cannot be used, use the mechanical key to open
the trunk. (→ P. 8 1 0 )
Connect the jumper cables according to the following procedure:
The following procedures may be used to start the hybrid system if the
12-volt battery is discharged.
You can also call your Lexus dealer or a qualified repair shop.
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Page 819 of 918

8187-2. Steps to take in an emergency
ES350_300h_OM_OM33A60U_(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 level 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 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 your Lexus dealer.
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 your Lexus
dealer as soon as possible.1
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Page 820 of 918

8197-2. Steps to take in an emergency
ES350_300h_OM_OM33A60U_(U)
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When trouble arises
■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 components 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 hybrid system may be unable to start. (The 12-volt battery recharges
automatically while the hybrid system is operating.)
■When recharging or replacing the 12-volt battery
●Make sure that the key is not inside the vehicle when recharging or replacing the
12-volt battery. The key may be locked in the vehicle if the alarm is activated.
(→ P. 8 7 )
●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 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 return to the mode it was in before the 12-volt bat-
tery was discharged. Before disconnecting the 12-volt battery, turn the “POWER”
switch off.
If you are unsure what mode the “POWER” switch was in before the 12-volt battery
discharged, be especially careful when reconnecting the 12-volt battery.
Page 825 of 918

824
ES350_300h_OM_OM33A60U_(U)
7-2. Steps to take in an emergency
If your vehicle overheats (hybrid vehicles)
■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 sys-
tem, 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 cooling system for 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.
●The needle of the engine coolant temperature gauge ( →P. 9 5 )
enters the red zone or a loss of hybrid system power is experienced.
(For example, the vehicle speed does not increase.)
●“Hybrid System Overheat” ( →P. 780) is shown on the multi-informa-
tion display.
●Steam comes out from under the hood.
Correction procedures
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Page 826 of 918

8257-2. Steps to take in an emergency
ES350_300h_OM_OM33A60U_(U)
7
When trouble arises
The coolant level is satisfactory if it is between the “FULL” and
“LOW” line on the reservoir.Reservoir
“FULL”
“LOW”
Radiator cap
Add coolant if necessary.
Water can be used in an emer-
gency 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 sys-
tem on and off repeatedly. (The fans may not operate in freezing tempera-
tures.)
If the fans are not operating:
Stop the hybrid system immediatel y and contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
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Page 827 of 918
8267-2. Steps to take in an emergency
ES350_300h_OM_OM33A60U_(U)
■If “Hybrid System Overheat” is shown on the multi-information dis-
play
Stop 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 radi-
ator core (radiator) for any leaks.
Radiator
Cooling fans
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
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
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8277-2. Steps to take in an emergency
ES350_300h_OM_OM33A60U_(U)
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When trouble arises
Start the hybrid system and check for the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
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 indicator on the
“POWER” switch and the “READY” indicator are off.
When the hybrid system is 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 fan, which may lead to fin-
gers or clothing (especially a tie, a scarf or a muffler) getting caught, resulting in
serious injury.
●Do not loosen the radiator cap or the coolant reservoir cap while the hybrid sys-
tem and radiator are hot. High temperature steam or coolant could spray out.
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 additives.
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