2020 Lexus ES300h ECU

3617-2. Steps to take in an emergency
7
When trouble arises
If a tow truck is not available in an
emergency, your vehicle may be tem-
porarily towed using cables or chains
secured to the emergency towing eye-
lets. This should only be attempted on
hard surfaced roads for short distances
at under 18 mph (30 km/h).
A driver must be in the vehicle to steer
and operate the brakes. The vehicle’s
wheels, drive train, axles, steering and
brakes must be in good condition.
To have your vehicle towed by another
vehicle, the towing eyelet must be
installed to your vehicle. Install the tow-
ing eyelet using the following proce-
dure.
1 Take out the towing eyelet.
(P.379)
2 Remove the eyelet cover using a
flathead screwdriver.
To protect the bodywork, place a rag
between the screwdriver and the vehicle
body as shown in the illustration.
3Insert the towing eyelet into the
hole and tighten partially by hand.
4 Tighten down the towing eyelet
securely using a wheel nut wrench
or hard metal bar.
5 Securely attach cables or chains to
the towing eyelet.
Take care not to damage the vehicle body.
6Enter the vehicle being towed and
start the hybrid system.
If the hybrid system does not start, turn the
power switch to ON mode.
7Shift the shift lever to N and release
the parking brake.
When the shift lever cannot be shifted:
P.151
■While towing
If the hybrid system is off, the power assist
for the brakes and steer ing will not function,
making steering and braking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in trunk.
Emergency towing (vehicles
with a towing eyelet)
Emergency towing procedure
(vehicles with a towing eyelet)

3717-2. Steps to take in an emergency
7
When trouble arises
■Brake hold operated indicator (warning buzzer)
■Hybrid system overheat warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■Master warning light (warning buzzer)
■Warning buzzer
In some cases, the bu zzer may not be heard
due to being in a noisy location or audio
sound.
■Front passenger detection sensor, seat
belt reminder and warning buzzer
●If luggage is placed on the front passen-
ger seat, the front passenger detection
sensor may cause th e warning light to
flash and the warning buzzer to sound
even if a passenger is not sitting in the
seat.
●If a cushion is placed on the seat, the sen-
sor may not detect a passenger, and the
warning light may not operate properly.
■SRS warning light
This warning light system monitors the air-
bag sensor assembly, fr ont impact sensors,
side impact sensors (front door), side
impact sensors (front), side impact sensors
(rear), driver’s seat position sensor, driver’s
seat belt buckle switch, front passenger
occupant classification system (ECU and
sensors), “AIR BAG ON” indicator light, “AIR BAG OFF” indicator light, front pas-
senger’s seat belt buckle switch, seat belt
pretensioners, airbags, interconnecting wir-
ing and power sources. (
P.28)
■Electric power steering system warning
light (warning buzzer)
When the 12-volt battery charge becomes
insufficient or the voltage temporarily
drops, the electric power steering system
warning light may come on and the warning
buzzer may sound.
■When the tire pressure warning light
comes on
Inspect the tires to check if a tire is punc-
tured.
If a tire is punctured:  P.378
If none of the tires are punctured:
Turn the power switch off then turn it to ON
mode. Check if the tire pressure warning
light comes on or blinks.
Warning lightDetails/Actions
(flashes)
Indicates a malfunction in the brake hold system
 Have the vehicle inspected by your Lexus dealer immediately.
Warning lightDetails/Actions
Indicates that the hybrid system has overheated
Stop the vehicle in a safe place. Handling method ( P.396)
Warning lightDetails/Actions
A buzzer sounds and the warning light comes on and flashes to indicate
that the master warning system has detected a malfunction.
 P.374

3817-2. Steps to take in an emergency
7
When trouble arises
3The lever can be hooked on the
edge of the trunk.
4
Remove the jack.
1
Remove the auxiliary box. 2
Loosen the center fastener that
secures the spare tire.
1
Chock the tires.
NOTICE
■To prevent damage to luggage mat
When closing the trunk door, do not
leave the luggage mat lever hooked on
the edge of the trunk.
Taking out the spare tire
WARNING
■When storing the spare tire
Be careful not to catch fingers or other
body parts between the spare tire and
the body of the vehicle.
Replacing a flat tire
Flat tireWheel chock positions
Front left-
hand sideBehind the rear right-hand
side tire
Front right-
hand sideBehind the rear left-hand
side tire
Rear left-hand
sideIn front of the front right-
hand side tire
Rear right-
hand sideIn front of the front left-
hand side tire

3857-2. Steps to take in an emergency
7
When trouble arises
One of the following may be the cause
of the problem:
The electronic key may not be func-
tioning properly. ( P.389)
 There may not be sufficient fuel in
the vehicle’s tank.
Refuel the vehicle. ( P.170)
 There may be a malfunction in the
immobilizer system. ( P.67)
 There may be a malfunction in the
steering lock system.
 The hybrid system may be malfunc-
tioning due to an electrical problem
such as electronic key battery
depletion or a blown fuse. However,
depending on the type of malfunc-
tion, an interim measure is available
to start the hybrid system.
One of the following may be the cause
WARNING
■Speed limit when using the compact
spare tire
Do not drive at speeds in excess of 50
mph (80 km/h) when a compact spare
tire is installed on the vehicle.
The compact spare tire is not designed
for driving at high speeds. Failure to
observe this precaution may lead to an
accident causing deat h or serious injury.
■After using the tools and jack
Before driving, make sure all the tools
and jack are securely in place in their
storage location to reduce the possibility
of personal injury during a collision or
sudden braking.
NOTICE
■Be careful when driving over bumps
with the compact spare tire installed
on the vehicle
The vehicle becomes lower when driving
with the compact spare tire compared to
when driving with standard tires. Be
careful when driving over uneven road
surfaces.
■Driving with tire chains and the com-
pact spare tire
Do not fit tire chains to the compact
spare tire.
Tire chains may damage the vehicle body
and adversely affect driving perfor-
mance.
■When replacing the tires
When removing or fitting the wheels,
tires or the tire pressure warning valve
and transmitter, contact your Lexus
dealer as the tire pr essure warning valve
and transmitter may be damaged if not
handled correctly.
If the hybrid system will not
s
tart
Reasons for the hybrid system not
starting vary depending on the situ-
ation. Check the following and per-
form the appropriate procedure:
The hybrid system will not start
even though the correct starting
procedure is being followed.
(  P.143)
The interior lights and head-
lights are dim, or the horn does
not sound or sounds at a low vol-
ume.

3927-2. Steps to take in an emergency
6Open and close any of the doors of
your vehicle with the power switch
off.
7 Maintain the engine speed of the
second vehicle and start the hybrid
system of your vehicle by turning
the power switch to ON mode.
8 Make sure the “READY” indicator
comes on. If the indicator does not
come on, contact your Lexus
dealer.
9 Once the vehicle’s hybrid system
has started, remove the jumper
cables in the exact reverse order
from which they were connected.
10 Close the exclusive jump starting
terminal cover, and reinstall the fuse
box cover to its original position.
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 sys-
tem while the hybrid system is stopped.
●Turn off any unnecessary electrical com-
ponents when the vehicle is running at a
low speed for an extended period, such
as in heavy traffic.
■When the 12-volt battery is removed or
discharged
●Information stored in the ECU is cleared.
When the 12-volt battery is depleted,
have the vehicle inspected at your Lexus
dealer.
●Some systems may require initialization.
(  P.429)
■When removing the 12-volt battery ter-
minals
When the 12-volt battery terminals are
removed, the information stored in the
ECU is cleared. Before removing the 12-
volt battery terminals, contact your Lexus
dealer.
■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 dis-
charge and the draining effects of certain
electrical 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.)
■When recharging or replacing the 12-
volt battery
●In some cases, it may not be possible to
unlock the doors using the smart access
system with push-button start when the
12-volt battery is discharged. Use the
wireless remote control or the mechani-
cal key to lock or unlock the doors.
●The hybrid system may not start on the
first attempt after the 12-volt battery has
recharged but will start normally after the
second attempt. This is not a malfunction.
●The power switch mode is memorized by
the vehicle. When the 12-volt battery is
reconnected, the system will return to the
mode it was in before the 12-volt battery
was discharged. Before disconnecting
the 12-volt battery, turn the power switch
off.
If you are unsure what mode the power
switch was in before the 12-volt battery
discharged, be especially careful when
reconnecting the 12-volt battery.
■When replacing the 12-volt battery
●Use a 12-volt battery that conforms to
European regulations.
●Use a 12-volt battery that the case size is
same as the previous one (LN2), 20 hour
rate capacity (20HR) is equivalent
(60Ah) or greater, and performance rat-
ing (CCA) is equivalent (345A) or
greater.

3937-2. Steps to take in an emergency
7
When trouble arises
• If the sizes differ, the 12-volt battery can-not be properly secured.
• 12-volt battery performance may decrease and the hybrid system may not
be able to start.
• If the 20 hour rate capacity is low, even if the time period where the vehicle is not
used is a short time, the 12-volt battery
may discharge and hybrid system may
not be able to start.
●Use a 12-volt battery with a handle. If a
12-volt battery without a handle is used,
removal is more difficult.
●After exchanging, firmly attach the fol-
lowing items to the exhaust hole of the 12-
volt battery.
• Use the exhaust hose that was attached
to the 12-volt battery before exchanging.
• Use the exhaust hole plug included with the 12-volt battery exchanged or the one
installed on the battery prior to the
exchange. (Depending on the 12-volt
battery to be exchanged, the exhaust
hole may be plugged.)
Exhaust hole plug
Exhaust hole
Exhaust hose
For details, consult your Lexus dealer.
A
B
C
WARNING
■When removing the 12-volt battery
terminals
Always remove the negative (-) terminal
first. If the positive (+) terminal contacts
any metal in the surrounding area when
the positive (+) terminal is removed, a
spark may occur, leading to a fire in addi-
tion to electrical shocks and death or
serious injury.
■Avoiding 12-volt battery fires or
explosions
Observe the following precautions to
prevent accidentally igniting the flamma-
ble gas that may be emitted from the 12-
volt battery:
●Make sure each jumper cable is con-
nected to the correct terminal and that
it is not unintentiona lly in contact with
any other than the intended terminal.
●Do not allow the other end of the
jumper cable connected to the “+” ter-
minal to come into contact with any
other parts or metal surfaces in the
area, such as brackets or unpainted
metal.
●Do not allow the + and - clamps of the
jumper cables to come into contact
with each other.
●Do not smoke, use matches, cigarette
lighters or allow open flame near the
12-volt battery.
■12-volt battery precautions
The 12-volt battery contains poisonous
and corrosive acidic electrolyte, while
related parts contain lead and lead com-
pounds. Observe the following precau-
tions when handling the 12-volt battery:
●When working with the 12-volt battery,
always wear safety glasses and take
care not to allow any 12-volt battery
fluids (acid) to come into contact with
skin, clothing or the vehicle body.
●Do not lean over the 12-volt battery.

3947-2. Steps to take in an emergency
WARNING
●In the event that 12-volt battery fluid
comes into contact with the skin or
eyes, immediately wash the affected
area with water and seek medical
attention.
Place a wet sponge or cloth over the
affected area until medical attention
can be received.
●Always wash your hands after handling
the 12-volt battery support, terminals,
and other battery-related parts.
●Do not allow children near the 12-volt
battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at
your Lexus dealer as soon as possible. If
the 12-volt battery is deteriorating, con-
tinued use may cause the 12-volt battery
to emit a malodorous gas, which may be
detrimental to the health of passengers.
■When exchanging the 12-volt battery
●When the vent plug and indicator are
close to the hold down clamp, the bat-
tery fluid (sulfuric acid) may leak.
●After exchanging, securely attach the
exhaust hose and exhaust hole plug to
the exhaust hole of the exchanged 12-
volt battery. If not properly installed,
gases (hydrogen) may leak into the
vehicle interior, and there is the possi-
ble danger of the gas igniting and
exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fan or engine drive
belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another vehicle in an emer-
gency. It cannot be used to jump start
another vehicle.

4178-1. Specifications
8
Vehicle specifications
*:Table 1  Occupant loading and distribution for vehicle normal load for various desig-
nated seating capacities
Snow tire
A tire that attains a traction index equal to or greater than 110, com-
pared to the ASTM E-1136 Standard Reference Test Tire, when using
the snow traction test as described in ASTM F-1805-00, Standard
Test Method for Single Wheel Driving Traction in a Straight Line on
Snow-and Ice-Covered Surfaces, and which is marked with an
Alpine Symbol ( ) on at least one sidewall
Test rimThe rim on which a tire is fitted fo r testing, and may be any rim listed
as appropriate for use with that tire
TreadThat portion of a tire that comes into contact with the road
Tread ribA tread section running circumferentially around a tire
Tread separationPulling away of the tread from the tire carcass
Treadwear indica-
tors (TWI)The projections within th e principal grooves designed to give a visual
indication of the degree s of wear of the tread
Wheel-holding fix-
tureThe fixture used to hold the wheel and tire assembly securely during
testing
Designated seating capacity,
Number of occupantsVehicle normal load, Num- ber of occupantsOccupant distribution in a normally loaded vehicle
2 through 422 in front
5 through 1032 in front, 1 in second seat
11 through 1552 in front, 1 in second seat, 1 in
third seat, 1 in fourth seat
16 through 2072 in front, 2 in second seat, 2 in third seat, 1 in fourth seat
Tire related termMeaning