2018 LEXUS LS500H ECU

4237-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 7
When trouble arises
In the following situations, it is not pos-
sible to be towed by another vehicle
using cables or chains, as the rear
wheels may be locked due to the park-
ing lock. Contact your Lexus dealer or
commercial towing service.
 There is a malfunction in the shift control system. ( → P.171, 437)
 There is a malfunction in the immo-
bilizer system. ( → P.66)
 There is a malfunction in the smart
access system with push-button
start. ( → P.445)
 The 12-volt battery is discharged.
( → P.447)
The following may indicate a problem
with your transmission. Contact your
Lexus dealer or commercial towing
service before towing.
 The hybrid system warning message
is shown on the multi-information
display and the vehicle does not
move.
 The vehicle makes an abnormal
sound.
Do not tow with a sling-type truck to
prevent body damage.WARNING■
Installing towing eyelets to the vehi-
cle
Make sure that towing eyelets are
installed securely.
If not securely installed, towing eyelets
may come loose during towing.
NOTICE■
To prevent damage to the vehicle
when towing using a wheel-lift type
truck●
Do not tow the vehicle from the rear
when the power switch is off. The
steering lock mechanism is not strong
enough to hold the front wheels
straight.●
When raising the vehicle, ensure ade-
quate ground clearance for towing at
the opposite end of the raised vehicle.
Without adequate clearance, the vehi-
cle could be damaged while being
towed.■
To prevent damage to the vehicle
when towing with a sling-type truck
Do not tow with a sling-type truck, either
from the front or rear.
■
To prevent damage to the vehicle
during emergency towing
Do not secure cables or chains to the
suspension components.
Situations when it is not possible
to be towed by another vehicle Situations when it is necessary to
contact dealers before towing
Towing with a sling-type truck

424 7-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 
From the front
Use a towing dolly under the rear
wheels. 
From the rear
Use a towing dolly under the front
wheels.
If your vehicle is transported by a flat-
bed truck, it should be tied down at the
locations shown in the illustration. If you use chains or cables to tie down
your vehicle, the angles shaded in
black must be 45°.
Do not overly tighten the tie downs or
the vehicle may be damaged.
Make sure to disable all functions of
the vehicle height control of the elec-
tronically modulated air suspension.
Otherwise, the vehicle height may
change and the vehicle may be dam-
aged. ( → P.301)
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 Towing with a wheel-lift type
truck
Using a flatbed truck
Emergency towing

4257-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 7
When trouble arises 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 phillips-head screw-
driver and towing eyelet.
Phillips-head screwdriver
Towing eyelet
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. 3 Insert the towing eyelet into the
hole and tighten partially by hand.
4 Tighten down the towing eyelet
securely using a phillips-head
screwdriver or hard metal bar.
5 Securely attach cables or chains to
the towing eyelet. Take care not to damage the vehicle body.
6 Enter the vehicle being towed and
start the hybrid system. If the hybrid system does not start, turn the
power switch to ON mode.
7 Shift the shift position to N and
release the parking brake. ■
While towing
If the hybrid system is off, the power assist
for the brakes and steering will not function,
making steering and braking more difficult.Emergency towing procedure
A
B

434 7-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) ■
Parking brake indicator
■
Brake hold operated indicator (warning buzzer)
■
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, Pop Up Hood com-
puter assembly, front 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 occu-
pant classification system (ECU and sen-
sors), rear seat belt buckle switches (if
equipped), “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.29)
■
If the malfunction indicator lamp comes
on while driving
First check the following:
●
Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●
Is the fuel tank cap loose?Warning light Details/Actions(flashes)
(U.S.A.)
or (flashes)
(Canada) Indicates a malfunction in the parking brake system
→ Have the vehicle inspected by your Lexus dealer immediately.
Warning light Details/Actions(flashes)
Indicates a malfunction in the brake hold system
→ Have the vehicle inspected by your Lexus dealer immediately.
Warning light Details/Actions
A buzzer sounds and the warning light comes on and flashes to indicate
that the master warning system has detected a malfunction.
→ P.437

4357-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 7
When trouble arises If it is, tighten it securely.
The light will go off after several driving
trips.
If the light does not go off even after several
trips, contact your Lexus dealer as soon as
possible. ■
Electric power steering system warning
light (warning buzzer)
When the 12-volt battery charge becomes
insufficient or the voltage temporarily
drops, the electric po wer 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.442
If none of the tires are punctured:
Turn the power switch off then turn it to ON
mode. Check if the ti re pressure warning
light comes on or blinks. 
If the tire pressure wa rning light blinks for
approximately 1 minute then stays on
There may be a malfunction in the tire
pressure warning syst em. Have the vehicle
inspected by your Lexus dealer immedi-
ately. 
If the tire pressure warning light comes
on
1 After the temperature of the tires has
lowered sufficiently, check the inflation
pressure of each tire and adjust them to
the specified level.
2 If the warning light does not turn off
even after several minutes have
elapsed, check that the inflation pres-
sure of each tire is at the specified level
and perform initialization. ( → P.401)
■
The tire pressure warning light may
come on due to natural causes
The tire pressure wa rning light may come
on due to natural causes such as natural air
leaks and tire inflation pressure changes
caused by temperature. In this case, adjust-
ing the tire inflation pressure will turn off the
warning light (after a few minutes). ■
Conditions that the tire pressure warn-
ing system may not function properly
→ P.398
WARNING■
If both the ABS and the brake system
warning lights remain on
Stop your vehicle in a safe place immedi-
ately and contact your Lexus dealer.
The vehicle will become extremely
unstable during br aking, and the ABS
system may fail, which could cause an
accident resulting in death or serious
injury. ■
When the electric power steering
system warning light comes on
When the light comes on yellow, the
assist to the power st eering is restricted.
When the light comes on red, the assist
to the power steering is lost and handling
operations of the steering wheel become
extremely heavy.
When steering wheel operations are
heavier than usual, grip the steering
wheel firmly and operate it using more
force than usual. ■
If the tire pressure warning light
comes on
Be sure to observe the following precau-
tions.
Failure to do so could cause a loss of
vehicle control and result in death or
serious injury.
●
Decelerate to the lowest appropriate
speed as soon as possible. Do not
drive over 50 mph (80 km/h).
●
Check and adjust the tire inflation
pressure immediately.
●
If the tire pressure warning light comes
on even after tire inflation pressure
adjustment, it is prob able that you have
a flat tire. Have the flat tire replaced by
the nearest Lexus dealer.

450 7-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 6 Open 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 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 install the fuse
box cover and en gine compart-
ment cover.
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 off.
●
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.495)■
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 Central Degassing type 12-volt
battery (European Regulations).
●
Use a 12-volt battery with the same case
size as the previous 12-volt battery and an
epuivalent 20 hour rate capacity (20HR)
or greater.

4517-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) 7
When trouble arises • If the sizes differ, the 12-volt battery can-
not be properly secured.
• 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 the 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 replacing, firmly attach the follow-
ing items to the exhaust hole of the
12-volt battery.
• Use the exhaust hose that was attached
to the 12-volt battery before replacing
and confirm that it is firmly connected to
the hole section of the vehicle.
• Use the exhaust hole plug included with
the 12-volt battery replaced or the one
installed on the 12-volt battery prior to
the replacement. (Depending on the
12-volt battery to be replaced, 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 meta l 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 battery fluids
(acid) to come into contact with skin,
clothing or the vehicle body.
●
Do not lean over the 12-volt battery.

452 7-2. Steps to take in an emergency
LS500h_OM_OM50F42U_(U) WARNING●
In the event that 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 batter y-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 replacing 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.●
For information regarding 12-volt bat-
tery replacement, contact your Lexus
dealer.
●
After replacing, securely attach the
exhaust hose and exhaust hole plug to
the exhaust hole of the replaced
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.