Page 895 of 1014
8687-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
Inte-
rior
buzzerExterior
buzzerWarning messageDetailsCorrection
procedure
Power was turned
off due to the
automatic power
off function.
Next time
when start-
ing the
hybrid sys-
tem,
increase
the engine
speed
slightly
and main-
tain that
level for
approxi-
mately 5
minutes to
recharge
the 12-volt
battery.
Once
The electronic
key has a low bat-
tery.
Replace
the elec-
tronic key
battery.
(P. 779)
Page 931 of 1014

9047-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
If the hybrid system will not start
One of the following may be the cause of the problem:
The electronic key may not be functioning properly. (P. 911)
There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle.
There may be a malfunction in the immobilizer system. (P. 91)
There may be a malfunction in the steering lock system.
The hybrid system may be malfunctioning due to an electrical
problem such as electronic key battery depletion or a blown fuse.
However, depending on the type of malfunction, an interim mea-
sure is available to start the hybrid system. (P. 905)
One of the following may be the cause of the problem:
The 12-volt battery may be discharged. (P. 913)
The 12-volt battery terminal connections may be loose or cor-
roded.
Reasons for the hybrid system not starting vary depending on the
situation. Check the following and perform the appropriate proce-
dure:
The hybrid system will not start even though the correct start-
ing procedure is being followed. (P. 246)
The interior lights and headlights are dim, or the horn does not
sound or sounds at a low volume.
Page 932 of 1014

905
7 7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
One of the following may be the cause of the problem:
One or both of the 12-volt battery terminals may be discon-
nected.
The 12-volt battery may be discharged. (P. 913)
Contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional if the problem cannot be repaired, or if repair
procedures are unknown.
When the hybrid system does not start, the following steps can be
used as an interim measure to start the hybrid system if the power
switch is functioning normally:
Set the parking brake.
Shift the shift lever to P.
Turn the power switch to ACCESSORY mode.
Press and hold the power switch for about 15 seconds while
depressing the brake pedal firmly.
Even if the hybrid system can be started using the above steps, the
system may be malfunctioning. Have the vehicle inspected by any
authorized Lexus dealer or repairer, or another duly qualified and
equipped professional.
The interior lights and headlights do not turn on, or the horn
does not sound.
Emergency start function
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Page 934 of 1014
9077-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
If the parking brake cannot be released
Shift the shift lever to P.
Turn the power switch off.
Check that the parking brake indicator is off.
Chock the tires.
In the event that the 12-volt battery is discharged or switch opera-
tion does not release the parking brake, the parking brake can be
released manually using the procedure below. This procedure
should be performed only if necessary, such as in an emergency.
If the switch cannot be operated even when the 12-volt battery is
normal, the parking brake system may be malfunctioning. Have the
vehicle inspected by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional immediately.
Before releasing the parking brake manually
Page 937 of 1014
9107-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
If the electronic key does not operate properly
Doors
Use the mechanical key
(P. 139) in order to perform
the following operations:
Locks all the doors
Closes the windows and
moon roof (turn and hold)
*
Unlocks all the doors
Opens the windows and
moon roof (turn and hold)
*
*
: This setting must be customized
at any authorized Lexus dealer
or repairer, or another duly qual-
ified and equipped professional.
If communication between the electronic key and vehicle is inter-
rupted (P. 150) or the electronic key cannot be used because the
battery is depleted, the smart entry & start system and wireless
remote control cannot be used. In such cases, the doors and trunk
can be opened and the hybrid system can be started by following
the procedure below.
Locking and unlocking the doors, unlocking the trunk and key
linked functions
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2
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Page 939 of 1014

9127-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
Stopping the hybrid system
Shift the shift lever to P and press the power switch as you normally do when
stopping the hybrid system.
Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the
electronic key battery be replaced immediately when the battery is depleted.
(P. 779)
Alarm (if equipped)
Using the mechanical key to lock the doors will not set the alarm system.
If a door is unlocked using the mechanical key when the alarm system is set,
the alarm may be triggered.
Changing power switch modes
Release the brake pedal and press the power switch in step above.
The hybrid system does not start and modes will be changed each time the
switch is pressed.(P. 247)
When the electronic key does not work properly
Make sure that the smart entry & start system has not been deactivated in
the customization setting. If it is off, turn the function on.
(Customizable features: P. 942)
Check if battery-saving mode is set. If it is set, cancel the function. (P.
149)
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Page 940 of 1014

9137-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
If the 12-volt battery is discharged
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.
In the event that the trunk opener
cannot be used, use the mechanical
key to open the trunk. (P. 910)
Connect the jumper cables according to the following procedure:
Positive (+) battery terminal on your vehicle
Positive (+) battery terminal on the second vehicle
Negative (-) battery terminal on the second vehicle
Negative (-) battery terminal on your vehicle
Start the engine of the second vehicle. Increase the engine speed
slightly and maintain at that level for approximately 5 minutes to
recharge the 12-volt battery of your vehicle.
The following procedures may be used to start the hybrid system if
the 12-volt battery is discharged.
You can also call any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
1
2
1
2
3
4
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Page 941 of 1014

9147-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
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 any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
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 any
authorized Lexus dealer or repairer, or another duly qualified and
equipped professional as soon as possible.
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 electrical appliances. If the vehicle is left for a long time,
the 12-volt battery may discharge, and the hybrid system may be unable to
start. (The 12-volt battery recharges automatically while the hybrid system is
operating.)
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