ECU LEXUS LS500 2018 Workshop Manual

3796-3. Do-it-yourself maintenance
LS500_OM_OM50F54U_(U) 6
Maintenance and care ■
Removing the service cover
1 Pull up the passenger side end of
the rubber strip to disengage it
from the vehicle body.
2 Remove the service cover.Push the tabs and lift away the service
cover.
■
Installing the service cover
1 Install the service cover.Make sure to engage the claws on the
windshield side of the service cover when
installing the service cover. 2 Engage the rubber strip to the vehi-
cle body.
With the engine at operating tempera-
ture and turned off, check the oil level
on the dipstick. ■
Checking the engine oil
1 Park the vehicle on level ground.
After warming up the engine and
turning it off, wait more than 5 min-
utes for the oil to drain back into the
bottom of the engine.
2 Holding a rag under the end, pull
the dipstick out.
 2WD models
 AWD modelsService cover NOTICE■
Checking the service cover after
installation
Make sure that the cover is securely
installed in its original position.
Checking and adding the engine
oil

4076-3. Do-it-yourself maintenance
LS500_OM_OM50F54U_(U) 6
Maintenance and care 
Type D
Normal fuse
Blown fuse ■
After a fuse is replaced●
When installing the lid, make sure that the
tab is installed securely.●
If the lights do not turn on even after the
fuse has been replaced, a bulb may need
replacement.●
If the replaced fuse blows again, have the
vehicle inspected by your Lexus dealer.■
If there is an overload in a circuit
The fuses are designed to blow, protecting
the wiring harness from damage.
WARNING■
To prevent system breakdowns and
vehicle fire
Observe the following precautions.
Failure to do so may cause damage to
the vehicle, and possibly a fire or injury.
●
Never use a fuse of a higher amperage
rating than that indicated, or use any
other object in place of a fuse.
●
Always use a genuine Lexus fuse or
equivalent.
Never replace a fuse with a wire, even
as a temporary fix.
●
Do not modify the fuses or fuse boxes. A
B NOTICE■
Before replacing fuses
Have the cause of electrical overload
determined and repaired by your Lexus
dealer as soon as possible.

410 7-1. Essential information
LS500_OM_OM50F54U_(U) 7-1.Essential information
Press the switch to flash all of the turn
signal lights. To turn them off, press the switch once
again.
■
Emergency flashers●
If the emergency flashers are used for a
long time while the engine is not running,
the battery may discharge.●
If any of the SRS airbags deploy (inflate)
or in the event of a strong rear impact, the
emergency flashers will turn on automati-
cally.
The emergency flashers will turn off auto-
matically after operating for approxi-
mately 20 minutes. To manually turn the
emergency flashers off, press the switch
twice.
(The emergency flashers may not turn on
automatically depending on the force of
the impact and conditions of the colli-
sion.) 1 Steadily step on the brake pedal
with both feet and firmly depress it. Do not pump the brake pedal repeatedly
as this will increase the effort required to
slow the vehicle.
2 Shift the shift position to N. 
If the shift position is shifted to N
3 After slowing down, stop the vehi-
cle in a safe place by the road.
4 Stop the engine. 
If the shift position cannot be shifted
to N
3 Keep depressing the brake pedal
with both feet to reduce vehicle
speed as much as possible.
4 To stop the engine, press and hold
the engine switch for 2 consecutive Emergency flashers The emergency flashers are used to
warn other drivers when the vehicle
has to be stopped on the road due
to a breakdown, etc.
Operating instructions If your vehicle has to be
stopped in an emergency Only in an emergency, such as if it
becomes impossible to stop the
vehicle in the normal way, stop the
vehicle using the following proce-
dure:
Stopping the vehicle

4137-2. Steps to take in an emergency
LS500_OM_OM50F54U_(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.163, 428)
 There is a malfunction in the engine
immobilizer system. ( → P.58)
 There is a malfunction in the smart
access system with push-button
start. ( → P.436)
 The battery is discharged.
( → P.438)
The following may indicate a problem
with your transmission. Contact your
Lexus dealer or commercial towing
service before towing.
 The engine is running but the vehi-
cle 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 engine 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

414 7-2. Steps to take in an emergency
LS500_OM_OM50F54U_(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.293)
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

4157-2. Steps to take in an emergency
LS500_OM_OM50F54U_(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 engine. If the engine does not start, turn the engine
switch to IGNITION ON mode.
7 Shift the shift position to N and
release the parking brake. ■
While towing
If the engine is not running, the power assist
for the brakes and steering will not function,
making steering and braking more difficult.Emergency towing procedure
A
B

4257-2. Steps to take in an emergency
LS500_OM_OM50F54U_(U) 7
When trouble arises ■
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.428

426 7-2. Steps to take in an emergency
LS500_OM_OM50F54U_(U) 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 battery charge becomes insuffi-
cient or the voltage temporarily drops, the
electric power steeri ng 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.432
If none of the tires are punctured:
Turn the engine switch off then turn it to
IGNITION ON mode. Check if the tire
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.392)
■
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.389
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.

4417-2. Steps to take in an emergency
LS500_OM_OM50F54U_(U) 7
When trouble arises low speed for an extended period, such
as in heavy traffic.■
When the battery is removed or dis-
charged●
Information stored in the ECU is cleared.
When the battery is depleted, have the
vehicle inspected at your Lexus dealer.●
Some systems may require initialization.
( → P.482)■
When removing the battery terminals
When the battery terminals are removed,
the information stored in the ECU is
cleared. Before removi ng the battery termi-
nals, contact your Lexus dealer. ■
Charging the battery
The electricity stored in the battery will dis-
charge gradually even when the vehicle is
not in use, due to natural discharge and the
draining effects of certain electrical appli-
ances. If the vehicle is left for a long time,
the battery may discharge, and the engine
may be unable to start. (The battery
recharges automatically during driving.) ■
When recharging or replacing the bat-
tery●
In some cases, it may not be possible to
unlock the doors using the smart access
system with push-button start when the
battery is discharged. Use the wireless
remote control or the mechanical key to
lock or unlock the doors.●
The engine may not start on the first
attempt after the battery has recharged
but will start normally after the second
attempt. This is not a malfunction.●
The engine switch mode is memorized by
the vehicle. When the battery is recon-
nected, the system will return to the
mode it was in before the battery was dis-
charged. Before di sconnecting the bat-
tery, turn the engine switch off.
If you are unsure what mode the engine
switch was in befo re the battery dis-
charged, be especially careful when
reconnecting the battery.
■
When replacing the battery
●
Use a Central Degassing type battery
(European Regulations). ●
Use a battery with the same case size as
the previous battery and an epuivalent
20 hour rate capacity (20HR) or greater.
• If the sizes differ, the battery cannot 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 battery may dis-
charge and the engine may not be able to
start. ●
Use a battery with a handle. If a battery
without a handle is used, removal is more
difficult. ●
After replacing, firm ly attach the follow-
ing items to the exhaust hole of the bat-
tery.
• Use the exhaust hose that was attached
to the battery before replacing and con-
firm that it is firmly connected to the hole
section of the vehicle.
• Use the exhaust hole plug included with
the battery replaced or the one installed
on the battery prior to the replacement.
(Depending on the 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

4678-1. Specifications
LS500_OM_OM50F54U_(U) 8
Vehicle specifications *
: Table 1 -Occupant loading and distribution for vehicle normal load for various desig-
nated seating capacitiesTreadwear indicators (TWI) The projections within the principal grooves
designed to give a visual indication of the degrees
of wear of the tread
Wheel-holding fixture The fixture used to hold the wheel and tire assembly
securely during testingTire related term Meaning
Designated seating capac-
ity, Number of occupants Vehicle normal load, Num-
ber of occupants Occupant distribution in a
normally loaded vehicle
2 through 4 2 2 in front
5 through 10 3 2 in front, 1 in second seat
11 through 15 5 2 in front, 1 in second seat, 1 in
third seat, 1 in fourth seat
16 through 20 7 2 in front, 2 in second seat, 2
in third seat, 1 in fourth seat