steering LEXUS RC350 2019 Service Manual

1644-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810Lane departure alert function is operating.
Operation display of steering
wheel operation support
Indicates that steering
wheel assistance of
the steering control function is operating.
Lane departure alert function dis-
play
Displayed when the mu lti-information dis-
play is switched to the driving assist system
information screen.
Inside of displayed white lines is
white
Indicates that the system is recognizing
white (yellow) lines. When the vehicle
departs from its lane , the white line dis-
played on the side the vehicle departs from
flashes orange.
Inside of displayed white lines is
black
Indicates that the system is not able to rec-
ognize white (yellow) lines or is temporar-
ily canceled.
■Operation conditions of each function
●Lane departure alert function
This function operates when all of the fol-
lowing conditions are met.
• LDA is turned on.
• Vehicle speed is ap proximately 32 mph
(50 km/h) or more.
• System recognizes white (yellow) lines.
• Width of traffic lane is approximately 9.8 ft. (3 m) or more.
• Turn signal lever is not operated.
• Vehicle is driven on a straight road or around a gentle curve with a radius of
more than approximately 492 ft. (150 m).
• No system malfunctions are detected.
( P.166)
●Steering control function
This function operates when all of the fol-
lowing conditions are met in addition to the
operation conditions for the lane depar-
ture alert function.
• Setting for “Steering Assist” in of the multi-information display is set to “On”.
( P.71)
• Vehicle is not acceler ated or decelerated
by a certain amount or more.
• Steering wheel is not operated with a steering force level su itable for changing
lanes.
• ABS, VSC, TRAC and PCS are not oper- ating.
• TRAC or VSC is not turned off.
• Hands off steering wheel warning is not displayed. ( P.165)
●Vehicle sway warning function
This function operates when all of the fol-
lowing conditions are met.
• Setting for “Sway Warning” in of the multi-information display is set to “On”.
( P.71)
• Vehicle speed is ap proximately 32 mph
(50 km/h) or more.
• Width of traffic lane is approximately 9.8 ft. (3 m) or more.
• No system malfunctions are detected. ( P.166)
■Temporary cancellation of functions
When the operation conditions are no lon-
ger met, a function may be temporarily can-
B
C

1654-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
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4
Driving
celed. However, wh en the operation
conditions are met again, operation of the
function is automatically restored. ( P.164)
■Steering control function
Depending on the vehicle speed, lane
departure situation, ro ad conditions, etc.,
the driver may not feel the function is oper-
ating or the function may not operate at all.
■Lane departure alert function
The warning buzzer may be difficult to hear
due to external noise, audio playback, etc.
Also, it may be difficult to feel steering
wheel vibrations due to the road conditions
etc.
■Hands off steering wheel warning
When the system determines that the driver
has removed their hands from the steering
wheel while the steering control function is
operating, a warning message urging the
driver to hold the steering wheel and the
symbol shown in the illustration are dis-
played on the multi-information display.
If the driver continue s to keep their hands
off of the steering wheel, a warning mes-
sage and the symbol shown in the illustra-
tion are displayed on the multi-information
display, and the function is temporarily can-
celed. This warning also operates in the
same way when the driver continuously
operates the steering wheel only a small
amount. Always keep your hands on the
steering wheel when using this system,
regardless of warnings.
Depending on the vehicle and road condi-
tions, the warning may not operate.
■Vehicle sway warning function
When the system determines that the vehi-
cle is swaying while the vehicle sway warn-
ing function is operating, a buzzer sounds
and a warning message urging the driver to rest and the symbol sh
own in the illustration
are simultaneously displayed on the
multi-information display.
Depending on the vehicle and road condi-
tions, the warning may not operate.
■White (yellow) lines are only on one side
of road
The LDA system will not operate for the
side on which white (yellow) lines could not
be recognized.
■Conditions in whic h functions may not
operate properly
In the following situations, the camera sen-
sor may not detect white (yellow) lines and
various functions may not operate normally.
●There are shadows on the road that run
parallel with, or cover, the white (yellow)
lines.
●The vehicle is driven in an area without
white (yellow) lines, su ch as in front of a
tollgate or checkpoint, or at an intersec-
tion, etc.
●The white (yellow) lines are cracked,
“Botts’ dots”, “Raised pavement marker”
or stones are present.
●The white (yellow) lines cannot be seen
or are difficult to see due to sand, etc.
●The vehicle is driven on a road surface
that is wet due to rain, puddles, etc.
●The traffic lines are yellow (which may be
more difficult to reco gnize than lines that
are white).
●The white (yellow) lines cross over a curb,
etc.
●The vehicle is driven on a bright surface,
such as concrete.
●The vehicle is driven on a surface that is
bright due to reflected light, etc.
●The vehicle is driven in an area where the

1674-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
4
Driving
If a different warning message is displayed, fo llow the instructions displayed on the screen.
■Customization
The following settings can be changed.
For how to change settings, refer to P.339
“Lane Departure Alert Unavailable
Below Approx 32MPH”
The LDA system cannot be used as the vehicle
speed is less than approx imately 32 mph (50 km/h).
 Drive the vehicle at approximately 32 mph (50
km/h) or more.
“Lane Departure Alert Unavailable
at Current Speed”The LDA system cannot be used as the vehicle
speed is too high.
 Slow down.
Warning messageDetails/Actions
FunctionSetting details
Lane departure
alert functionAdjust alert sensitivity
Adjust alert type
Steering control
functionTurn steering wheel
assistance on and off
Vehicle sway
warning functionTurn function on and
off
Adjust alert sensitivity

1904-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
Vehicles without Adaptive Variable
Suspension System
1 Normal mode
Provides an optimal ba lance of fuel econ-
omy, quietness, and dynamic performance.
Suitable for city driving.
Press the switch to change the driving
mode to normal mode when Eco drive
mode or sport mode is selected.
2 Eco drive mode
Helps the driver accelerate in an
eco-friendly manner and improve fuel
economy through moderate throttle char-
acteristics and by controlling the operation
of the air conditioning system (heat-
ing/cooling).
When not in Eco drive mode, if the driving
mode select switch is turned to the left, the
Eco drive mode indicator will come on.
3Sport mode
Controls the transmission and engine to
provide quick, powerful acceleration. This
mode also changes the steering feel, mak-
ing it suitable for when agile driving
response is desired, such as when driving
on roads with many curves.
When not in sport mode, if the driving
mode select switch is turned to the right,
the “SPORT” indicator will comes on.
Vehicles with Adaptive Variable
Suspension System
1 Normal mode/Custom mode
Normal mode and custom mode are
selected by pressing the driving mode
select switch. Each time the switch is
pressed, the driving mode changes
between normal mode and custom mode.
When custom mode is selected, the “CUS-
TOM” indicator will be illuminated.
When Eco drive mode or sport mode is
selected, pressing th e switch changes the
driving mode to normal mode.
• Normal mode
Provides an optimal ba lance of fuel econ-
omy, quietness, and dynamic performance.
Suitable for city driving.
• Custom mode
Allows you to drive with the following func-
tions set to your preferred settings.
Driving mode select switch
The driving modes can be selected
to suit driving condition.
Selecting a drive mode

1914-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
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4
Driving
Custom mode settings can only be
changed on the drive mode customization
display of the Center Display. ( P.202)
2 Eco drive mode
Helps the driver accelerate in an
eco-friendly manner and improve fuel
economy through moderate throttle char-
acteristics and by controlling the operation
of the air conditioning system (heat-
ing/cooling).
When not in Eco drive mode, if the driving
mode select switch is turned to the left, the
Eco drive mode indicator will come on.
3Sport mode
•SPORT S mode
Controls the transmission and engine to
provide quick, powerful acceleration. Also,
gear shift timing is co ntrolled to suit sporty
driving, making this mode is suitable for
when agile driving response is desired,
such as when driving on roads with many
curves.
When not in SPORT S mode, if the driving
mode select switch is turned to the right,
the “SPORT S” indicator will come on.
•SPORT S+ mode
Provides earlier down shift timing than
SPORT S mode in order to maintain a high
engine speed and provides faster gear
changes. This mode also changes the steering feel, susp
ension control and
VDIM control, making it suitable for pow-
erful sporty driving.
When in SPORT S mode, if the driving
mode select switch is turned to the right,
the “SPORT S+” indicator will come on.
■Operation of the air conditioning sys-
tem in Eco drive mode
Eco drive mode controls the heating/cool-
ing operations and fan speed of the air con-
ditioning system to enhance fuel efficiency
(  P.205). To improve air conditioning per-
formance, adjust the fan speed or turn off
Eco drive mode.
■Automatic deactivation of sport mode
and custom mode
If the engine switch is turned off after driv-
ing in sport mode or custom mode, the
drive mode will be changed to normal
mode.
■Driving mode pop-up display (vehicles
with a 10.3-inch display)
When the driving mode is changed, the
selected driving mode will be temporarily
displayed on the side display. ( P.202)
FunctionSetting
Powertrain
Normal
Power
Eco
ChassisNormal
Sport
Air conditioning sys-
temNormal
Eco

1924-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
■ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the
brakes are applied suddenly, or if the
brakes are applied while driving on a
slippery road surface
■Brake assist
Generates an increased level of brak-
ing force after the brake pedal is
depressed when the system detects a
panic stop situation
■VSC (Vehicle Stability Control)
Helps the driver to control skidding
when swerving sudden ly or turning on
slippery road surfaces
■Enhanced VSC (Enhanced Vehi-
cle Stability Control)
Provides cooperative control of the
ABS, TRAC, VSC and EPS.
Helps to maintain directional stability
when swerving on slippery road sur-
faces by controlling steering perfor-
mance.
■TRAC (Traction Control)
Helps to maintain drive power and pre-
vent the drive wheels from spinning
when starting the vehicle or accelerat-
ing on slippery roads
■Hill-start assist control
Helps to prevent the vehicle from roll-
ing backward when starting on an
incline
■VGRS (Variable Gear Ratio Steer-
ing) (if equipped)
Adjusts the front wheel turning angle in
accordance with the vehicle speed and
steering wheel movement
■DRS (Dynamic Rear Steering) (if
equipped)
Contributes to the turning characteris-
tics and responsiveness of the vehicle
by adjusting the rear wheel angle of the
vehicle in accordance with steering
wheel movement.
■EPS (Electric Power Steering)
Employs an electric motor to reduce
the amount of effort needed to turn the
steering wheel
■Adaptive Variable Suspension Sys-
tem (if equipped)
By independently controlling the
damping force of th e shock absorbers
for each of the 4 wheels according to
the road and driving conditions, this
system combines riding comfort with
superior vehicle stability, and helps
good vehicle posture.
Driving assist systems
To help enhance driving safety and
performance, the following systems
operate automatically in response
to various driving situations. Be
aware, however, that these systems
are supplementary and should not
be relied upon too heavily when
operating the vehicle.
Summary of the driving assist
systems

1934-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
4
Driving
■LDH (Lexus Dynamic Handling
system) (if equipped)
Provides integrated control of the
VGRS, DRS and EPS. Contributes to
turning characteristics at low speeds,
responsiveness at medium speeds and
safety at high speeds by controlling the
steering angle of the front and rear
wheels in accordance with the steering
wheel operation and vehicle speed.
■VDIM (Vehicle Dynamics Inte-
grated Management)
Provides integrated control of the
ABS, brake assist, TRC, VSC, hill-start
assist control, EPS, VGRS (if
equipped) and DRS (if equipped) sys-
tems
Helps to maintain vehicle stability when
swerving on slippery road surfaces by
controlling the brakes, engine output,
steering assist, and if equipped with
VGRS, steering ratio
■When the TRAC/VSC systems are
operating
The slip indicator light will flash while the
TRAC/VSC systems are operating.
■Disabling the TRAC system
If the vehicle gets stuck in mud, dirt or snow,
the TRAC system may reduce power from
the engine to the wheels. Pressing the
switch to turn the system off may make it
easier for you to rock the vehicle in order to free it.
To turn the TRAC system off, quickly press
and release the switch.
The “Traction Co
ntrol Turned Off” will be
shown on the multi-information display.
Press the switch ag ain to turn the sys-
tem back on.
■Turning off both TRAC and VSC sys-
tems
To turn the TRAC and VSC systems off,
press and hold the switch for more
than 3 seconds while the vehicle is stopped.
The VSC OFF indicator light will come on
and the “Traction Control Turned Off” will
be shown on the multi-information display.
*
Press the switch ag ain to turn the sys-
tems back on.
*: On vehicles with PCS (Pre-Collision System), pre-collision brake assist,
pre-collision braking, and steering con-
trol (performed through cooperative
control of PCS and LDH) (if equipped)
will also be disabled. The Pre-Collision
System warning light will come on and a
message will be di splayed on the
multi-information display. ( P.160)

1944-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
■When the message is displayed on the
multi-information display showing that
TRAC has been disabled even if the switch has not been pressed
TRAC cannot be operated. Contact your
Lexus dealer.
■Operating conditions of hill-start assist
control
When the following four conditions are met,
the hill-start assist control will operate:
●The shift lever is in a position other than P
or N (when starting off forward/back-
ward on an upward incline).
●The vehicle is stopped.
●The accelerator pedal is not depressed.
●The parking brake is not engaged.
■Automatic system cancelation of
hill-start assist control
The hill-start assist control will turn off in any
of the following situations:
●The shift lever is moved to P or N.
●The accelerator pedal is depressed.
●The parking brake is engaged.
●Approximately 2 seconds elapse after
the brake pedal is released.
■VGRS is disabled when
VGRS may stop operating in the following
situations.
In this event, the steering wheel may move
from its straight forward position, but it will
return when the system restarts.
●When the steering wheel is operated for
an extended period of time while the
vehicle is stopped or is moving very
slowly
(on vehicles with LDH, DRS is disabled
together with VGRS)
●When the steering wheel has been held
fully to the left or right
The center position of the steering wheel
may change when VGRS is disabled. How-
ever, the position will return to normal after
VGRS is reactivated.
■When the battery is disconnected (vehi-
cles with VGRS)
The steering wheel may move from its
straight forward position, but this will be
corrected automatically when driving.
■Sounds and vibrations caused by the
ABS, brake assist, VSC, TRAC, hill-start
assist control and VGRS systems
●A sound may be heard from the engine
compartment when the brake pedal is
depressed repeatedly, when the engine is
started or just after the vehicle begins to
move. This sound does not indicate that a
malfunction has occurred in any of these
systems.
●Any of the following conditions may
occur when the above systems are oper-
ating. None of these indicates that a mal-
function has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the
vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.
■EPS, VGRS and DRS operation sound
When the steering wheel is operated, a
motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
■Reactivation of the TRAC/VSC systems
Even after the TRAC /VSC systems have
been turned off, turning the engine off and
then on again will automatically reactivate
the TRAC/VSC systems.
■Reactivation of the TRAC system linked
to vehicle speed
When only the TRAC system is turned off,
the TRAC system will turn on when vehicle
speed increases. Ho wever, when both
TRAC/VSC systems are turned off, the sys-
tems will not turn on even when vehicle
speed increases.
■Reduced effectiveness of the EPS sys-
tem
The effectiveness of the EPS system is
reduced to prevent the system from over-
heating when there is frequent steering

1954-5. Using the driving support systems
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
4
Driving
input over an extended period of time. The
steering wheel may feel heavy as a result.
Should this occur, re frain from excessive
steering input or stop the vehicle and turn
the engine off. The EPS system should
return to normal within 10 minutes.
WARNING
■The ABS does not operate effectively
when
●The limits of tire gripping performance
have been exceeded (such as exces-
sively worn tires on a snow covered
road).
●The vehicle hydroplanes while driving
at high speed on wet or slick roads.
■Stopping distance when the ABS is
operating may exceed that of normal
conditions
The ABS is not designed to shorten the
vehicle’s stopping di stance. Always main-
tain a safe distance from the vehicle in
front of you, especially in the following
situations:
●When driving on dirt, gravel or
snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes
or uneven surfaces
■TRAC may not operate effectively
when
Directional control and power may not
be achievable while driving on slippery
road surfaces, even if the TRAC system is
operating. Drive the vehicle carefully in
conditions where stability and power
may be lost.
■Hill-start assist control does not oper-
ate effectively when
●Do not overly rely on hill-start assist
control. Hill-start assist control may
not operate effectively on steep
inclines and roads covered with ice.
●Unlike the parking brake, hill-start
assist control is not intended to hold
the vehicle stationary for an extended
period of time. Do not attempt to use
hill-start assist control to hold the vehi-
cle on an incline, as doing so may lead
to an accident.
■When the VSC is activated
The slip indicator light flashes. Always
drive carefully. Reckless driving may
cause an accident. Exercise particular
care when the indicator light flashes.
■When the TRAC/VSC systems are
turned off
Be especially careful and drive at a speed
appropriate to the road conditions. As
these are the systems to help ensure
vehicle stability and driving force, do not
turn the TRAC/VSC systems off unless
necessary.
■Replacing tires
Make sure that all ti res are of the speci-
fied size, brand, tread pattern and total
load capacity. In addition, make sure that
the tires are inflated to the recom-
mended tire inflation pressure level.
The ABS, TRAC and VSC systems will
not function correctly if different tires are
installed on the vehicle.
Contact your Lexus dealer for further
information when replacing tires or
wheels.
■Handling of tires and the suspension
Using tires with any kind of problem or
modifying the suspensi on will affect the
driving assist systems, and may cause a
system to malfunction.

1964-6. Driving tips
RC350AWD_RC350_RC300AWD_RC30
0_OM_(U)_1810
4-6.Driving tips
Use fluids that are appropriate to
the prevailing outside temperatures.
• Engine oil
• Engine coolant
• Washer fluid
Have a service technician inspect
the condition of the battery.
 Have the vehicle fitted with four
snow tires or purchase a set of tire
chains for the rear tires.
*
Ensure that all tires are the specified size
and brand, and that chains match the size
of the tires.
*: Tire chains cannot be mounted on vehi-
cles with front and rear tires of differing
sizes and vehicles with LDH and 19-inch
tires.
Perform the following according to the
driving conditions:
 Do not try to forcibly open a window
or move a wiper that is frozen. Pour
Winter driving tips
Carry out the necessary prepara-
tions and inspections before driving
the vehicle in winter. Always drive
the vehicle in a manner appropriate
to the prevailing weather condi-
tions.
Preparation for winter
WARNING
■Driving with snow tires
Observe the following precautions to
reduce the risk of accidents.
Failure to do so may result in a loss of
vehicle control and cause death or seri-
ous injury.
●Use tires of the specified size.
●Maintain the recommended level of air
pressure.
●Do not drive in excess of 75 mph (120
km/h), regardless of the type of snow
tires being used.
●Use snow tires on all, not just some
wheels.
■Driving with tire chains
Observe the following precautions to
reduce the risk of accidents.
Failure to do so may result in the vehicle
being unable to be driven safely, and may
cause death or serious injury.
●Do not drive in excess of the speed
limit specified for the tire chains being
used, or 30 mph (50 km/h), which-
ever is lower.
●Avoid driving on bumpy road surfaces
or over potholes.
●Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.
●Slow down sufficiently before entering
a curve to ensure that vehicle control is
maintained.
●Do not use LDA (Lane Departure
Alert with steering control) system.
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow
tires from Lexus dealers or legitimate tire
retailers.
This is because the removal and attach-
ment of snow tires affects the operation
of the tire pressure warning valves and
transmitters.
Before driving the vehicle