Lexus ES300h 2020 (OM06196U) Repair Manual

611-4. Hybrid system
1
For safety and security
1-4.Hybrid system
The illustration is an example for explanation and may differ from the actual item.
Gasoline engine
Electric motor (traction motor)
■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 electric
motor (traction motor) is used.
When the shift lever is in N, the hybrid
battery (traction battery) is not being charged.
*: When the hybrid battery (traction bat-
tery) requires charging or the engine is
warming up, etc., the gasoline engine will
not automatically stop.
■During normal driving
The gasoline engine is predominantly
used. The electric motor (traction
motor) charges the hybrid battery
(traction battery) as necessary.
Hybrid system features
Your vehicle is a hybrid vehicle. It has characteristics different from conven-
tional vehicles. Be sure you are closely familiar with the characteristics of your
vehicle, and operate it with care.
The hybrid system combines the use of a gasoline engine and an electric motor
(traction motor) according to driving conditions, improving fuel efficiency and
reducing exhaust emissions.
System components
A
B

621-4. Hybrid system
■When accelerating sharply
When the accelerator pedal is
depressed heavily, the power of the
hybrid battery (traction battery) is
added to that of the gasoline engine via
the electric motor (traction motor).
■When braking (regenerative brak-
ing)
The wheels operate the electric motor
(traction motor) as a power generator,
and the hybrid battery (traction bat-
tery) is charged.
■Regenerative braking
In the following situations, kinetic energy is
converted to electric energy and decelera-
tion force can be obta ined in conjunction
with the recharging of the hybrid battery
(traction battery).
●The accelerator pedal is released while
driving with the shift lever in D or S.
●The brake pedal is depressed while driv-
ing with the shift lever in D or S.
■EV indicator
The EV indicator comes on when the vehi-
cle is driven using only the electric motor
(traction motor) or th e gasoline engine is
stopped.
■Conditions in which the gasoline engine
may not stop
The gasoline engine starts and stops auto-
matically. 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 bat-
tery (traction battery) is high or low
●When the heater is switched on*: Depending on the circumstances, the
gasoline engine may also not stop auto-
matically in other situations.
■Charging the hybrid battery (traction
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 (traction
battery) will slowly discharge. For this rea-
son, be sure to drive the vehicle at least
once every few months for at least 30 min-
utes or 10 miles (16 km ). If the hybrid bat-
tery (traction battery) becomes fully
discharged and you are unable to start the
hybrid system, contact your Lexus dealer.
■Charging the 12-volt battery
 P.392
■After the 12-volt battery has discharged
or when the terminal has been removed
and installed during exchange, etc.
The gasoline engine may not stop even if
the vehicle is being driven by the hybrid bat-
tery (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 sound or vibration
even though the vehicle is able to move with
the “READY” indicator is illuminated. For
safety, apply the parking brake and make
sure to shift the shift lever 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.
●Relay operating sounds such as a snap or

631-4. Hybrid system
1
For safety and security
soft clank will be emitted from the hybrid
battery (traction battery), behind the rear
seats, when the hybrid system is started
or stopped.
●Sounds from the hybrid system may be
heard when the trunk lid is open.
●Sounds may be heard from the transmis-
sion when the gasoline engine starts or
stops, when driving at low speeds, or
during idling.
●Engine sounds may be heard when
accelerating sharply.
●Sounds may be heard due to regenera-
tive braking when the brake pedal is
depressed or as the accelerator pedal is
released.
●Vibration may be felt when the gasoline
engine starts or stops.
●Cooling fan sounds may be heard from
the air intake vent under the rear seat.
■Maintenance, repair, recycling, and dis-
posal
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.418)
When driving with the gasoline engine
stopped, a sound, which changes in
accordance with the driving speed, will
be played in order to warn people
nearby of the vehicle’s approach. This
sound may be heard inside the vehicle.
The sound will stop when the vehicle
speed exceeds appr oximately 16 mph
(25 km/h).
■Vehicle proximity notification system
In the following cases, the vehicle proximity
notification system may be difficult for sur-
rounding 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 vehicle,
it may be more difficult to hear from the rear
of the vehicle compared to the front.
Vehicle proximity notification
system

641-4. Hybrid system
The illustration is an example for explanation and may differ from the actual item.
Warning label
Service plug
Hybrid battery (traction battery)
High voltage cables (orange)
Electric motor (traction motor)
Power control unit
Air conditioning compressor
■Running out of fuel
When the vehicle has run out of fuel and the
hybrid system cannot be started, refuel the
vehicle with at least enough gasoline to
make the low fuel level warning light
(  P.367) go off. If there is only a small
amount of fuel, the hybrid system may not
be able to start. (The standard amount of fuel is about 2.4gal. [9.0 L, 2.0 Imp.gal.],
when the vehicle is on a level surface. This
value may vary when the vehicle is on a
slope. Add extra fuel when the vehicle is
inclined.)
■Electromagnetic waves
●High voltage parts and cables on hybrid
vehicles incorporate electromagnetic
Hybrid system precautions
Take care when handling the hybrid system,
as it is a high voltage system (about
650 V at maximum) as well as contains parts that become extremely hot when
the hybrid system is operating. Obey th e warning labels attached to the vehi-
cle.
System components
A
B
C
D
E
F
G

651-4. Hybrid system
1
For safety and security
shielding, and therefore emit approxi-
mately the same amount of electromag-
netic waves as conventional gasoline
powered vehicles or home electronic
appliances.
●Your vehicle may cause sound interfer-
ence in some third party-produced radio
parts.
■Hybrid battery (traction battery)
The hybrid battery (traction battery) has a
limited service life. The lifespan of the
hybrid battery (traction battery) can
change in accordance with driving style and
driving conditions.
WARNING
■High voltage precautions
This 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 warning labels
attached to the vehicle.
●Never try to open the service plug
access hole located under the rear
seat (right side). The service plug is
used only when the vehicle is serviced
and is subject to high voltage.
■Road accident cautions
Observe the following precautions to
reduce the risk of death or serious injury:
●Stop the vehicle in a safe place to pre-
vent subsequent accidents. While
depressing the brake pedal, apply the
parking brake and sh ift the shift lever
to P to stop the hybrid system. Then,
slowly release the brake pedal.
●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 elec-
tric wires.
●If a fluid leak occurs, do not touch the
fluid as it may be st rong alkaline elec-
trolyte from the hybrid battery (trac-
tion 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 solu-
tion. Seek immediate medical atten-
tion.
●If electrolyte is leaking from the hybrid
battery (traction battery), do not
approach the vehicle.
Even in the unlikely event that the
hybrid battery (traction battery) is
damaged, the internal construction of
the battery will prev ent a large amount
of electrolyte from leaking out. How-
ever, any electrolyte that does leak out
will give off a vapor. This vapor is an
irritant to skin and eyes and could
cause acute poisoning if inhaled.
●Do not bring burning or high-tem-
perature items close to the electrolyte.
The electrolyte may ignite and cause a
fire.
●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 danger-
ous.

661-4. Hybrid system
There is an air intake vent under the
rear seat (right side) for the purpose of
cooling the hybrid battery (traction
battery). If the vent becomes blocked,
the hybrid battery (traction battery)
may overheat, leading to a reduction in
the hybrid battery (traction battery)
output.
WARNING
●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 a fire. ( P.359)
●Carefully inspect the ground under the
vehicle. If you find that liquid has
leaked onto the ground, the fuel sys-
tem may have been damaged. Leave
the vehicle as soon as possible.
■Hybrid battery (traction battery)
●Never resell, hand over or modify the
hybrid battery. To prevent accidents,
hybrid batteries that have been
removed from a disposed vehicle are
collected through Lexus dealer. Do not
dispose of the battery yourself.
Unless the battery is properly col-
lected, the following may occur, result-
ing in death or serious injury:
• The hybrid battery may be illegally dis- posed of or dumped, and it is hazard-
ous to the environment or someone
may touch a high voltage part, result-
ing in an electric shock.
• The hybrid battery is intended to be used exclusively with your hybrid vehi-
cle. If the hybrid battery is used outside
of your vehicle or modified in any way,
accidents such as electric shock, heat
generation, smoke generation, an
explosion and electrolyte leakage may
occur.
When reselling or handing over your
vehicle, the possibility of an accident is
extremely high because the person
receiving the vehicle may not be aware
of these dangers.
●If your vehicle is disposed of without
the hybrid battery having been
removed, there is a danger of serious
electric shock if hi gh voltage parts,
cables and their connectors are
touched. In the event that your vehicle
must be disposed of, the hybrid battery
must be disposed of by your Lexus
dealer or a qualified service shop. If
the hybrid battery is not disposed of
properly, it may cause electric shock
that can result in death or serious
injury.
NOTICE
■Hybrid battery (traction battery)
Do not carry large amounts of water
such as water cooler bottles in the vehi-
cle. If water spills onto the hybrid battery
(traction battery), the battery may be
damaged. Have the vehicle inspected by
your Lexus dealer.
Hybrid battery (traction bat-
tery) air intake vent

671-4. Hybrid system
1
For safety and security
When a certain level of impact is
detected by the impact sensor, the
emergency shut off system blocks the
high voltage current and stops the fuel
pump to minimize the risk of electrocu-
tion and fuel leakage. If the emergency
shut off system activates, your vehicle
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 opera-
tion is attempted.
If a warning message is shown on the
multi-information display, read the
message and follow the instructions.
■If a warning light comes on, a warning
message is displayed, or the 12-volt bat-
tery is disconnected
The hybrid system may not start. In this
case, try to start the system again. If the
“READY” indicator does not come on, con-
tact your Lexus dealer.
NOTICE
■Hybrid battery (traction battery) air
intake vent
●Make sure not to block the air intake
vent with anything, such as a seat
cover, plastic cover, or luggage. If the
vents become blocked, the hybrid bat-
tery (traction battery) input and output
may be restricted, leading to a reduc-
tion in hybrid battery (traction battery)
output and a malfunction.
●When dust etc. has accumulated in the
air intake vent, periodically clean it
with a vacuum cleaner to prevent the
vent from clogging.
●A filter is installed to the air intake vent.
When the filter remains noticeably
dirty even after cleaning the air intake
vent, filter cleaning or replacement is
recommended. When cleaning or
replacing the filter, contact your Lexus
dealer.
Refer to P.343 for details on how to
clean the filter.
●Do not get water or foreign materials
in the air intake 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 damaged. Have the vehicle
inspected by your
Lexus dealer.
Emergency shut off system
Hybrid warning message

681-5. Theft deterrent system
1-5.Theft deterrent 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 indi-
cate that the system has been can-
celed.
■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 touch-
ing a key registered to the security sys-
tem (key with a built-in transponder chip)
of another vehicle
■Certifications for the immobilizer system
For vehicles sold in the U.S.A. , Hawaii, Guam and Puerto Rico
Immobilizer system
The vehicle’s keys have built-in tran-
sponder 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 pre-
vent vehicle theft but does not guar-
antee absolute security against all
vehicle thefts.
Operating the system

691-5. Theft deterrent system
1
For safety and security
For vehicles sold in Canada
NOTICE
■To ensure the system operates cor-
rectly
Do not modify or remove the system. If
modified or removed, the proper opera-
tion of the system cannot be guaranteed.

701-5. Theft deterrent system
■Items to check before locking the
vehicle
To prevent unexpected triggering of
the alarm and vehicle theft, make sure
of the following:
 Nobody is in the vehicle.
 The windows and moon roof are
closed before the alarm is set.
 No valuables or other personal
items are left in the vehicle.
■Setting
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.
■Canceling or stopping
Do one of the following to deactivate
or stop the alarm:
 Unlock the doors.
 Turn the power switch to ACCES-
SORY or ON mode, or start the
hybrid system. (The alarm will be
deactivated or stopped after a few
seconds.)
■System maintenance
The vehicle has a maintenance-free type
alarm system.
■Triggering of the alarm
The alarm may be triggered in the following
situations:
(Stopping the alarm deactivates the alarm
system.)
●The trunk is unlocked using the mechani-
cal key.
●A person inside the vehicle opens a door,
the trunk or hood, or unlocks the vehicle
using a door lock switch.
Alarm
The alarm uses light and sound to
give an alert when an intrusion is
detected.
The alarm is triggered in the follow-
ing situations when the alarm is set:
 A locked door 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.)
 A locked trunk is unlocked or
opened in any way other than
using the entry function or wire-
less remote control.
 The hood is opened.
Setting/canceling/stopping the
alarm system