2015 Lexus GS450h ECU

731-2. Hybrid system
GS450h_OM_OM30F70U_(U)
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For safety and security
◆When stopped/during start off
The gasoline engine stops when the vehicle is stopped. During start off,
the electric motor (traction motor) drives the vehicle. At slow speeds or
when traveling down a gentle slope, the engine is stopped and the elec-
tric motor (traction motor) is used.
◆During normal driving
The gasoline engine is predominantl y used. The electric motor (traction
motor) charges the hybrid battery (traction battery) as necessary.
◆When accelerating sharply
When the accelerator pedal is depres sed heavily, the power of the
hybrid battery (traction batter y) is added to that of the gasoline engine
via the electric motor (traction motor).
◆When braking (regenerative braking)
The electric motor (traction motor) charges the hybrid battery (traction
battery).
When driving with the gasoline engine stopped, a sound, which changes
in accordance with the driving speed, w ill be played in order to warn peo-
ple nearby of the vehicle’s approach. The sound will stop when the vehicle
speed exceeds approximately 15 mph (25 km/h).
Vehicle proximity notification system

751-2. Hybrid system
GS450h_OM_OM30F70U_(U)
1
For safety and security
■After the 12-volt battery has discharged or has been changed or removed
The gasoline engine may not stop even if the vehicle is running on the hybrid battery
(traction battery). If this continues for a few days, contact your Lexus dealer.
■Sounds and vibrations specific to a hybrid vehicle
There may be no engine sounds or vibration even though the vehicle is able to move.
For safety, apply the parking brake and make sure to shift the shift position to P when
parked.
The following sounds or vibrations may occur when the hybrid system is operating
and are not a malfunction:
●Motor sounds may be heard from the engine compartment.
●Sounds may be heard from the hybrid battery (traction battery) behind the rear
seats when the hybrid system starts or stops.
●Sounds from the hybrid system may be heard when the trunk lid is open.
●Sounds may be heard from the hybrid tran smission when the hybrid system starts
or stops.
●Engine sounds may be heard when accelerating sharply.
●Sounds may be heard due to regenerative braking when the brake pedal is
depressed.
●Vibration may be felt when the gasoline engine starts or stops.
●Cooling fan sounds may be heard from the ai r intake vents on the both sides of the
rear seatback.
■Vehicle proximity notification system
In the following cases, the vehicle proximity notification system may be difficult for
surrounding people to hear.
●In very noisy areas
●In the wind or the rain
Also, as the vehicle proximity notification system is installed on the front of the vehi-
cle, it may be more difficult to hear from the rear of the vehicle compared to the
front.
■Maintenance, repair, recycling, and disposal
Contact your Lexus dealer regarding main tenance, repair, recycling and disposal.
Do not dispose of the vehicle yourself.
■Customization
Settings (e.g. on/off operation of the EV indicator) can be changed.
(Customizable features: P. 5 9 9 )

771-2. Hybrid system
GS450h_OM_OM30F70U_(U)
1
For safety and security
There are air intake vents on the
both sides of the rear seatback for
the purpose of cooling the hybrid
battery (traction battery). If the
vents become blocked, the hybrid
battery may overheat, leading to a
reduction in hybrid battery output.
When a certain level of impact is detected by the impact sensor, the emer-
gency shut off system blocks off the high voltage current and stops the fuel
pump to minimize the risk of electr ocution and fuel leakage. If the emer-
gency shut off system activates, your ve hicle will not restart. To restart the
hybrid system, contact your Lexus dealer.
A message is automatically displayed when a malfunction occurs in the
hybrid system or an improper operation is attempted.
If a warning message is shown on
the multi-information display, read
the message and follow the instruc-
tions.
( P. 513)
Hybrid battery (traction battery) air vents
Emergency shut off system
Hybrid warning message

791-2. Hybrid system
GS450h_OM_OM30F70U_(U)
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For safety and security
CAUTION
■High voltage precautions
The vehicle has high voltage DC and AC systems as well as a 12-volt system. DC
and AC high voltage is very dangerous and can cause severe burns and electric
shock that may result in death or serious injury.
●Never touch, disassemble, remove or re place the high voltage parts, cables or
their connectors.
●The hybrid system will become hot after starting as the system uses high voltage.
Be careful of both the high voltage and the high temperature, and always obey
the caution labels attached to the vehicle.
■Road accident cautions
Observe the following precautions to reduce the risk of death or serious injury:
●Pull your vehicle off the road, apply the parking brake, shift the shift lever to P, and
turn the hybrid system off.
●Do not touch the high voltage parts, cables and connectors.
●If electric wires are exposed inside or outside your vehicle, an electric shock may
occur. Never touch exposed electric wires.
●If a fluid leak occurs, do not touch the flui d as it may be strong alkaline electrolyte
from the hybrid battery (traction battery). If it comes into contact with your skin or
eyes, wash it off immediately with a large amount of water or, if possible, boric
acid solution. Seek imme diate medical attention.
●If a fire occurs in the hybrid vehicle, leave the vehicle as soon as possible. Never
use a fire extinguisher that is not meant for electric fires. Using even a small
amount of water may be dangerous.
●If your vehicle needs to be towed, do so with rear wheels raised. If the wheels
connected to the electric motor (traction motor) are on the ground when towing,
the motor may continue to generate electricity. This may cause an electricity
leakage leading to a fire. ( P. 4 9 6 )
●Carefully inspect the ground under the vehicle. If you find that liquid has leaked
onto the ground, the fuel system may have been damaged. Leave the vehicle as
soon as possible.
●Never try to open the service plug access
hole located behind the rear seats. The ser-
vice plug is used only when the vehicle is
serviced and is subject to high voltage.

811-3. Theft deterrent system
GS450h_OM_OM30F70U_(U)
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For safety and security
Immobilizer system
The indicator light flashes after the
power switch has been turned off to
indicate that the system is operating.
The indicator light stops flashing
after the power switch has been
turned to ACCESSORY or ON
mode to indicate that the system has
been canceled.
■System maintenance
The vehicle has a maintenance-free type immobilizer system.
■Conditions that may cause the system to malfunction
●If the grip portion of the key is in contact with a metallic object
●If the key is in close proximity to or touching a key to the security system (key with a
built-in transponder chip) of another vehicle
The vehicle’s keys have built-in tr ansponder chips that prevent the
hybrid system from starting if a key has not been previously registered
in the vehicle’s on-board computer.
Never leave the keys inside the vehicle when you leave the vehicle.
This system is designed to help prev ent vehicle theft but does not guar-
antee absolute security against all vehicle thefts.

831-3. Theft deterrent system
GS450h_OM_OM30F70U_(U)
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For safety and security
Alarm
The alarm uses light and sound to give an alert when an intrusion is
detected.
The alarm is triggered in the following situations when the alarm is set:
●A locked door or trunk is unlocked or opened in any way other than
using the entry function, wireless remote control or mechanical key.
(The doors will lock again automatically.)
●The hood is opened.
Close the doors, trunk and hood,
and lock all the doors. The system
will be set automatically after 30
seconds.
The indicator light changes from
being on to flashing when the system
is set.
Do one of the following to deactivate or stop the alarms:
●Unlock the doors or open the trunk.
●Turn the power switch to ACCESS ORY or ON mode, or start the
hybrid system. (The alarm will be deactivated or stopped after a few
seconds.)
The alarm
Setting the alarm system
Deactivating or stopping the alarm

123
GS450h_OM_OM30F70U_(U)3-2. Opening, closing and locking the doors and trunk
3
Operation of each component
Smart access system with push-button start
The following operations can be perf ormed simply by carrying the elec-
tronic key on your person, for exam ple in your pocket. (The driver should
always carry the electronic key.)
■Operation signals
A buzzer sounds and the emergency flashe rs flash to indicate that the doors have
been locked/unlocked. (Locked: once; Unlocked: twice)
■Security feature
If a door is not opened within approx imately 60 seconds after the vehicle is
unlocked, the security feature automatically locks the vehicle again.
■Welcome light illumination control
The side marker, parking, tail and license plate lights automatically turn on at night
when the doors are unlocked using the entr y function or wireless remote control if
the light switch is in the “AUTO” position.
Function summary
Locks and unlocks the doors ( P. 1 2 4 )
Opens the trunk ( P. 1 2 4 )
Starts the hybrid system ( P. 193)1
2
3

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GS450h_OM_OM30F70U_(U)
3-2. Opening, closing and locking the doors and trunk
Grip the driver’s door handle to
unlock the door. Grip the passen-
ger’s door handle to unlock all the
doors.*
Make sure to touch the sensor on the
back of the handle.
The doors cannot be unlocked for
3 seconds after the doors are locked.
*: The door unlock settings can be
changed. ( P. 1 2 8 )
Touch the lock sensor (the indenta-
tion on the upper part of the door
handle) to lock all the doors.
Check that the door is securely
locked.
Press the button.
If the vehicle is equipped with power
trunk opener and closer, the trunk lid
automatically opens fully.
Unlocking and locking the doors
Opening the trunk