2011 Lexus HS250h Do-it-yourself maintenance / LEXUS 2011 HS250H OWNERS MANUAL (OM75037U)

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1-1. Hybrid system
1
Before driving
■Regenerative braking
In the following situations, kinetic energy is converted to electric energy and decel-
eration force can be obtained in conjunction with the recharging of the hybrid bat-
tery (traction battery).
●The accelerator pedal is released while driving with shift position D or B
selected.
●The brake pedal is depressed while driving with shift position D or B selected.
■Conditions in which the gasoline engine may not stop
The gasoline engine starts and stops automatically. However, it may not stop auto-
matically in the following conditions:
●During gasoline engine warm-up
●During hybrid battery (traction battery) charging
●When the temperature of the hybrid battery (traction battery) is high or low
●When the heater is switched on
*: However, when the hybrid battery (traction battery) need to be
charged or while the engine is being warmed up, the gasoline
engine may not stop automatically.
■ During normal driving
The gasoline engine is predomina ntly used. The electric motor
(traction motor) charges the hybrid battery as necessary.
■ When accelerating sharply
The power of the hybrid battery (tract ion battery) is added to that of
the gasoline engine via the electric motor (traction motor).
■ When braking (regenerative braking)
The electric motor (traction moto r) charges the hybrid battery
(traction battery).

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1-1. Hybrid system
■Charging the battery
As the gasoline engine charges the hybrid battery (traction battery), the battery
does not need to be charged from an outside source. However, if the vehicle is left
parked for a long time the hybrid battery will slowly discharge. For this reason, be
sure to drive the vehicle at least once every few months for at least 30 minutes or
10 miles (16 km). If the hybrid battery becomes fully discharged and you are unable
to jump-start the vehicle with the 12-v olt battery, contact your Lexus dealer.
■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 vibrat ion even though the vehicle is able to
move. Always change the shift position to P, and apply the parking brake 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 fr om the engine compartment.
●Sounds may be heard from the hybrid ba ttery (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 transaxle when the engine is started or stopped,
or while the engine is idling.
●Engine sounds may be heard when accelerating sharply.
●Sounds may be heard due to regenera tive braking when the brake pedal is
depressed and accelerator is loosened.
●Other sounds, such as motors and mechanical noises, may be heard from the
brake system 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 air intake vent on the side of rear left
seatback.
When driving in Eco drive mode, the fan noise may be louder than when driving
normally.

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1-1. Hybrid system
1
Before driving
■Maintenance, repair, recycling, and disposal
Contact your Lexus dealer regarding maintenance, repair, recycling and disposal.
Do not dispose of the vehicle yourself.

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1-1. Hybrid system
Hybrid system precautions
Take care when handling the hybrid system, as it contains a high voltage
system (about 650V at maximum) as well as parts that become extremely
hot when the hybrid system is operat ing. Obey the caution labels attached
to the vehicle.
Air conditioning compressor
Power control unit
Hybrid battery (traction bat-
tery) and DC/DC converter
Service plug High voltage cables (orange)
Electric motor (traction motor)
Caution label

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1-1. Hybrid system
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Before driving
Hybrid battery air ventThere is an air intake vent on the
side of the rear left seatback for
the purpose of cooling the hybrid
battery (traction battery). If the
vent become blocked, the hybrid
battery may overheat, leading to a
reduction in hybrid battery output.
Emergency shut off system When a certain level of impact is detected by the impact sensor, the
emergency shut off system blocks off the high voltage current and stops
the fuel pump to minimize the risk of electrocution and fuel leakage. If the
emergency shut off system activates, your vehicle will not restart. To
restart the hybrid system, contact your Lexus dealer.
Hybrid warning message
A message is automatically displayed when a malfunction occurs in the
hybrid system or an impr oper operation is attempted.
If a warning message is shown on
the multi-information display, read
the message and follow the
instructions.
(P. 507)

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1-1. Hybrid system
■If a warning light comes on, a warning message is displayed, or the 12-volt battery
is disconnected
The hybrid system may not start. In that case, try to start the system again. If the
“READY” indicator does not come on, contact your Lexus dealer.
■Electromagnetic waves
●High voltage parts and cables on the hybrid vehicles incorporate electromag-
netic shielding, and theref ore emit approximately the same amount of electro-
magnetic waves as conventional gasoline powered vehicles or home electronic
appliances.
●Your vehicle may cause sound interference in some third party-produced radio
parts.
■Running out of fuel
When the vehicle has run out of fuel and th e hybrid system cannot be started, refuel
the vehicle with at least enough gasoline to make the low fuel level warning light
(  P. 501) go off. If there is only a small amount of fuel, the hybrid system may not
be able to start. (The minimum amount of fuel to add to make the low fuel level
warning light go out is about 2.6 gal. [10 L, 2.1 Imp.gal.], when the vehicle is on a
level surface. This value may vary when the vehicle is on a slope.)
■Hybrid battery (traction battery)
The hybrid battery (traction battery) has a limited service life. The lifespan of the
hybrid battery (traction battery) can chan ge in accordance with driving style and
driving conditions.

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1-1. Hybrid system
1
Before driving
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 replace 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, change the shift position to P, apply the parking
brake, 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 immediate medical attention.
●If a fire occurs in the hybrid vehicle, le ave 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.
●Never try to open the service plug access
hole located in the luggage compartment.
The service plug is used only when the
vehicle is serviced an d is subject to high
voltage.

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1-1. Hybrid system
CAUTION
●If your vehicle needs to be towed, do so with front 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 8 9 )
●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.
■Nickel-metal hydride battery
Your vehicle contains a sealed nickel-metal hydride battery. If disposed of improp-
erly, it is hazardous to the environment and there is a risk of severe burns and elec-
trical shock that may result in death or serious injury.
■Emergency shut off system
Carefully check to see if there are exposed high voltage parts or cables. Never
touch the parts or cables. (
P. 2 8 )
NOTICE
■Hybrid battery air vent
●Do not put foreign objects near the air ve nt. The hybrid battery (traction battery)
may overheat and be damaged.
●Clean the air vent regularly to prevent th e hybrid battery (traction battery) from
overheating.
●Do not wet or allow foreign substances to enter the air vent as this may cause a
short circuit and damage the hybrid battery (traction battery).
●Do not carry large amounts of water such as water cooler bottles in the vehicle. If
water spills onto the hybrid battery (traction battery), the battery may be dam-
aged. Have the vehicle inspected by your Lexus dealer.