Page 492 of 654
GS450h_OM_OM30F70U_(U)
4916-3. Do-it-yourself maintenance
6
Maintenance and care
CAUTION
■Discharge headlights (if equipped)
●Contact your Lexus dealer before replacing the discharge headlights (including
light bulbs).
●Do not touch the discharge headlight’s high voltage socket when the headlights
are turned on.
An extremely high voltage of 30000 V will be discharged and could result in
death or serious injury by electric shock.
●Do not attempt to take apart or repair the headlight bulbs, connectors, power
supply circuits, or related components.
Doing so could result in electric shock and death or serious injury.
■To prevent damage or fire
●Make sure bulbs are fully seated and locked.
●Check the wattage of the bulb before installing to prevent heat damage.
GS450h_OM_OM30F70U_(U).book Page 491 Monday, January 19, 2015 9:34 AM
Page 555 of 654

554
GS450h_OM_OM30F70U_(U)
7-2. Steps to take in an emergency
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. 560)
●There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle.
●There may be a malfunction in the immobilizer system. ( →P. 8 1 )
●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 measure is available
to start the hybrid system. ( →P. 555)
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. ( →P. 562)
●The 12-volt battery terminal connections may be loose or corroded.
Reasons for the hybrid system not st arting vary depending on the situa-
tion. Check the following and perform the appropriate procedure:
The hybrid system will not start even though the correct starting
procedure is being followed. ( →P. 1 9 3 )
The interior lights and headlights are dim, or the horn does not
sound or sounds at a low volume.
GS450h_OM_OM30F70U_(U).book Page 554 Monday, January 19, 2015 9:34 AM
Page 556 of 654

5557-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
7
When trouble arises
One of the following may be the cause of the problem:
●One or both of the 12-volt battery terminals may be disconnected.
●The 12-volt battery may be discharged. (→P. 562)
Contact your Lexus dealer if the problem cannot be repaired, or if repair proce-
dures 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 func-
tioning 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 your Lexus dealer.
The interior lights and headlights do not turn on, or the horn does
not sound.
Emergency start function
1
2
3
4
GS450h_OM_OM30F70U_(U).book Page 555 Monday, January 19, 2015 9:34 AM
Page 564 of 654

5637-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
7
When trouble arises
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.
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.
■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.)
3
4
5
6
7
GS450h_OM_OM30F70U_(U).book Page 563 Monday, January 19, 2015 9:34 AM
Page 584 of 654