wheel LEXUS RC350 2015 Service Manual

2824-5. Using the driving support systems
RC350/RCF_U (OM24636U)
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if the
brakes are applied while drivin g on a slippery road surface
◆Brake assist
Generates an increased level of braking 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 suddenly or turning on
slippery road surfaces
◆Enhanced VSC (Enhanced Vehicle 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 performance.
◆TRAC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from spinning
when starting the vehicle or accelerating on slippery roads
◆Hill-start assist control
Prevents the vehicle from rolling backward when starting on an incline or slip-
pery slope
◆VGRS (Variable Gear Ratio Steering) (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 characteristics and responsiveness of the vehicle
by slightly adjusting the rear wheel angle of the vehicle in accordance with
steering wheel movement.
Driving assist systems
To help enhance driving safety and performance, the following systems oper-
ate 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.

2834-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
◆EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn the
steering wheel
◆Adaptive Variable Suspension system (if equipped)
By independently controlling the dampin g force of the shock absorbers for
each of the 4 wheels according to the road and driving conditions, this system
combines riding comfort with superior steering stability, and helps good vehi-
cle posture. ( P. 2 7 9 )
◆LDH (Lexus Dynamic Handling system) (if equipped)
Provides integrated control of the VGRS, DRS and EPS. Contributes to turn-
ing characteristics at low speeds, re sponsiveness 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 Integrated Management)
Provides integrated control of the ABS, brake assist, TRAC, VSC, hill-start
assist control, EPS, VGRS (if equi pped) and DRS (if equipped) systems
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
◆PCS (Pre-Collision System) (if equipped)
 P. 2 9 0
◆BSM (Blind Spot Monitor) (if equipped)
P. 2 9 7
◆TVD (Torque Vectoring Differential) (if equipped)
P. 3 1 3

2844-5. Using the driving support systems
RC350/RCF_U (OM24636U)
The slip indicator light will flash while
the TRAC/VSC systems are operating.
If the vehicle gets stuck in mud, dirt or snow, the TRAC system may reduce
power from the engine to the wheels. Pressing (
) to turn the system
off may make it easier for you to rock the vehicle in order to free it.
RC350
To turn the TRAC system off, quickly
press and release .
The “TRAC OFF” will be shown on the
multi-information display.
Press again to turn the system
back on.
When the TRAC/VSC systems are operating
Disabling the TRAC system

2864-5. Using the driving support systems
RC350/RCF_U (OM24636U)
■Expert mode (RC F)
When expert mode is selected, it is possible to drive in a more sporty manner than other
drive modes. Expert mode disables the TRAC and VSC systems but the engine and
brakes may be controlled depending on the vehicle behavior.
■When the message is displayed on the mu lti-information display showing that TRAC
has been disabled even if has not been pressed (RC350)
TRAC and hill-start assist control cannot be operated. Contact your Lexus dealer.
■When the “TRAC OFF” indicator light comes on even if () has not been
pressed (RC F)
TRAC and hill-start assist control cannot be operated. Contact your Lexus dealer.
■VGRS is disabled when
VGRS may stop operating in the following situations.
In this event, the steering wheel may move fr om 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. However,
the position will return to normal after VGRS is reactivated.
■When the battery is disconnected (vehicles with VGRS)
The steering wheel may move fr om its straight forward position, but this will be corrected
automatically when driving. To select expert mode, press
()
when in SPORT S+ mode.
The “EXPERT” indicator will come on together
with the TRAC OFF and VSC OFF indicators.
To cancel expert mode, press
()
or use the driving mode se lect switch to select a
driving mode other than SPORT S+ mode.

2874-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
■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 sys-
tems.
●Any of the following condit ions may occur when the above systems are operating.
None of these indicates that a malfunction 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 slig htly after the ABS is activated.
• The brake pedal may move down s lightly after the ABS is activated.
■EPS, VGRS and DRS operation sound
When the steering wheel is operated, a motor sound may be heard. This does not indi-
cate 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. However, when both TRAC /VSC systems are turned off, the systems
will not turn on even when vehicle speed increases.
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from overheating
when there is frequent steering input over an extended period of time. The steering
wheel may feel heavy as a result. Should this occur, refrain from excessive steering input
or stop the vehicle and turn the engine of f. The EPS system should return to normal
within 10 minutes.
■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/backward 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.

2894-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
WA R N I N G
■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 st ability and driving force, do not turn the
TRAC/VSC systems off unless necessary.
■Expert mode precautions
●Do not use on public roads.
●Use only when the road conditions and safety of the surrounding area can be
ensured.
●Proper use of expert mode requires a profes sional level of driving skill. When using
expert mode, always check the road conditions and surrounding area and drive more
carefully than usual.
■Replacing tires
Make sure that all tires are of the specified size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire infla-
tion 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 modi fying the suspension will affect the driving
assist systems, and may caus e a system to malfunction.

2914-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
◆Steering control (if equipped)
When the system determines that there is a high possibility of a frontal colli-
sion while the steering wheel is being operated, the LDH (Lexus Dynamic
Handling) system controls the steering angle of the front and rear wheels and
torque applied to the steering wheel to enhance the steering wheel operation
response.
Enabled
Disabled
The pre-collision system warning light
comes on when pre-collision system is
disabled.
The radar sensor detects vehicles or
other obstacles on or near the road
ahead and determines whether a colli-
sion is imminent based on the position,
speed, and heading of the obstacles.
Disabling pre-collision system
1
2
Radar sensor

2934-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
■Conditions that may trigger the system even if there is no danger of a collision
In the following situations, the front of the sensor may be obstructed causing the system
to determine that there is a poss ibility of a collision and operate:
●When passing an oncoming vehicle on a cu rb or while making a left or right turn
●When rapidly closing on an obstruction in front of the vehicle, such as a vehicle or toll
gate
●When climbing a hill, and an overhead structure (billboard, low ceiling, street lamps,
etc.) appears in the vehicle’s line of travel
●When driving through a narrow passage or a place with a low ceiling (bridges, tunnels,
overhead passes, etc.)
●When driving on an uneven road surface
●When there is a metal object on the road surf ace, or a gap or protrusion in the road sur-
face
●When there is an extreme change in the vehicle height
●When the sensor is misaligned due to a stro ng impact to the surrounding area of the
sensor
●When there is an object on the side of the road at the entrance to a curve, such as
guardrails
●When the front of your vehicle is inclined (during emergency towing, carrying a heavy
load in the trunk, etc.)
When the system is activated in the situations described above, there is also a possibility
that the brakes will be applied with a force greater than normal.
■Obstacles not detected
The sensor cannot detect plasti c obstacles such as traffic cones. There may also be occa-
sions when the sensor cannot detect pedestrians, animals, bicycles, motorcycles, trees,
or snowdrifts.
■Situations in which the pre-collision system does not function properly
The system may not function effectively in situations such as the following:
●On roads with sharp bends or uneven surfaces
●If a vehicle suddenly moves in front of your vehicle, such as at an intersection
●If a vehicle suddenly cuts in front of your vehicle, such as when overtaking
●In inclement weather such as heavy rain, fog, snow or sand storms
●If the vehicle is skidding when VSC is not operating
●When your vehicle is steeply inclined
●When the radar sensor moves off position due to its surrounding area being subjected
to a strong impact
●When an obstacle suddenly appears in front of the vehicle due to the steering wheel
being turned sharply or another cause
■Automatic cancelation of the pre-collision system
When a malfunction occurs due to sensor cont amination, etc. that results in the sensors
being unable to detect obstacles, the pre-collision syst em will be automatically disabled.
In this case, the system will not activate even if there is a collision possibility.
■When there is a malfunction in the system or if the system is temporarily unusable
The pre-collision system warning light will flash or illuminate and warning messages will
be displayed. ( P. 5 3 4 , 5 4 5 )

2954-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
WA R N I N G
■Limitations of the pre-collision system
●The driver is solely responsible for safe driving. Always drive safely, taking care to
observe your surroundings.
Never use the pre-collision safety system instead of normal braking operations. This
system is not designed to avoid or reduce collisions in every situation. Overly relying
on the system or entrusting it with safety may lead to an accident resulting in death or
serious injury.
Although this system is designed to suppor t in avoiding a collision or reducing the
damage of a collision, its effectiveness may change according to various conditions
(  P. 292, 293). Therefore, the system may not always provide the same perfor-
mance. Also, pre-collision braking function may not operate depending on the oper-
ations of the driver. If the driver is stepping on the brake pedal or is operating the
steering wheel, the system may determine th at the driver is taking evasive action and
pre-collision braking func tion may not operate.
●As the pre-collision system is designed to assi st the driver in safe driving, it may oper-
ate under sporty driving conditions, whic h may cause an accident. For this reason
under sporty driving conditions, it is reco mmended that this system be disabled by
using the PCS OFF switch.
■Handling the radar sensor
Observe the following to ensure the pre-collision system can function effectively.
Otherwise, the system may not function correctly and could result in an accident.
●Keep the sensor and grille cover clean at all times.
Clean the sensor and grille cover with a soft cloth so you do not mark or damage
them.
●Do not subject the sensor or surr ounding area to a strong impact.
If the sensor moves even slightly off posi tion, the system may become inaccurate or
malfunction. If the sensor or surrounding area is subject to a strong impact, always
have the area inspected and adjusted by your Lexus dealer.
●Do not disassemble the sensor.
●Do not attach accessories or stickers to the sensor, grille cover or surrounding area.
●Do not modify or paint the sensor and grille cover.
●If the radar sensor needs to be replaced, contact your Lexus dealer.

3134-5. Using the driving support systems
4
Driving
RC350/RCF_U (OM24636U)
With the engine switch in IGNITION
ON mode, pressing the TVD switch
changes the TVD control mode.
The current TVD control mode will be
displayed on the meters.
STANDARD mode
This is the default mode and pro-
vides an optimum balance of driving
agility and stability.
SLALOM mode
This mode emphasizes enhanced
steering response.
TRACK mode
This mode emphasizes stability for
high speed sporty driving.
The multi-information display shows the distribution of driving force between the
right and left rear wheels. ( P. 1 1 0 )
TVD (Torque Vectoring Differential)

: If equipped
The TVD system distributes driving force (torque) between the right and left
rear wheels automatically. This syst em contributes to enhanced steering
response while cornering and increased traction when exiting a corner, pro-
viding an agile driving experience.
Changing TVD control modes
1
2
3
TVD control status on the multi-information display