2012 Lexus IS250C brakes

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2-4. Using other driving systems
CAUTION
■Before using dynamic radar cruise control
Do not overly rely on vehicle-to-vehicle distance control.
Be aware of the set speed. If automatic deceleration/acceleration is not appropri-
ate, adjust the vehicle speed, as well as the distance between your vehicle and vehi-
cles ahead by applying the brakes etc.
■Cautions regarding the driving assist systems
Observe the following precautions.
Failure to do so may cause an accident resulting in death or serious injury.
●Assisting the driver to measure following distance
The dynamic radar cruise control is only in tended to help the driver in determin-
ing the following distance between the driver’s own vehicle and a designated
vehicle traveling ahead. It is not a mechanism that allows careless or inattentive
driving, and it is not a system that can assi st the driver in low-visibility conditions. It
is still necessary for driver to pay clos e attention to the vehicle’s surroundings.
●Assisting the driver to judge proper following distance
The dynamic radar cruise control determines whether the following distance
between the driver’s own vehicle and a designated vehicle traveling ahead is
appropriate or not. It is not capable of making any other type of judgement.
Therefore, it is absolutely necessary for the driver to remain vigilant and to deter-
mine whether or not there is a possibil ity of danger in any given situation.
●Assisting the driver to operate the vehicle
The dynamic radar cruise control has no capability to prevent or avoid a collision
with a vehicle traveling ahead. Therefore, if there is ever any danger, the driver
must take immediate and direct control of the vehicle and act appropriately in
order to ensure the safety of all involved.

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2-4. Using other driving systems
2
When driving
CAUTION
■To avoid inadvertent cruise control activation
Switch the cruise control off using the “ON-OFF” button when not in use.
■Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise contro l in any of the following situations.
Doing so may result in inappropriate sp eed control and could cause an accident
resulting in death or serious injury.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as thos e covered with rain, ice or snow
●On steep downhills, or where there are sudden changes between sharp up and
down gradients
Vehicle speed may exceed the set speed when driving down a steep hill.
●At entrances to expressways
●When weather conditions are bad enough that they may prevent the sensors
from functioning correctly (fog, sn ow, sandstorm, heavy rain, etc.)
●When an approach warning buzzer is heard often
●During emergency towing
■When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are in
front of you.
As the sensor may not be able to correctly detect these types of vehicles, the
approach warning (P. 205) will not be activated, and a fatal or serious accident
may result.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving
●Vehicles with small rear ends (tra ilers with no load on board etc.)
●Motorcycles traveling in the same lane

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2-4. Using other driving systems
CAUTION
■Conditions under which the vehicle-to-vehicle distance control may not function
correctly
Apply the brakes as necessary in the following conditions as the radar sensor may
not be able to correctly detect vehicles ahead, and a fatal or serious accident may
result.
●When water or snow thrown up by the surrounding vehicles hinders the function-
ing of the sensor
●When your vehicle is pointing upwards (c aused by a heavy load in the trunk etc.)
●When the road curves or when the lanes are narrow
●When steering wheel operation or your position in the lane is unstable
●When the vehicle ahead of you decelerates suddenly
■Handling the radar sensor
Observe the following to ensure the cruise control 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 surrounding area to a strong impact.
If the sensor moves even slightly off position, the system may malfunction. If the
sensor or surrounding area is subject to a strong impact, always have the area
inspected and adjusted by a 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.
●Do not replace them with non-genuine parts.

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2-4. Using other driving systems
2
When driving
■Sensor detection information
●Certain vehicle conditions and the surrounding environment may affect the
ability of the sensor to correctly detect obstacles. Particular instances where this
may occur are listed below.
• There is dirt, snow or ice on the sensor.
• The sensor is frozen.
• The sensor is covered in any way.
• The vehicle is leaning considerably to one side.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• The vicinity of the vehicle is noisy due to vehicle horns, motorcycle engines,
air brakes of large vehicles, or other loud noises producing ultrasonic waves.
• There is another vehicle equipped with parking assist sensors in the vicinity.
• The sensor is coated with a sheet of spray or heavy rain.
• The vehicle is equipped with a fender pole or wireless antenna.
• Towing eyelets are installed.
• The bumper or sensor receives a strong impact.
• The vehicle is approaching a tall or curved curb.
• In harsh sunlight or intense cold weather
In addition to the examples above, there are instances in which, because of their
shapes, signs and other object s may be judged by the sensor to be closer than they
are.
●The shape of the obstacle may prevent th e sensor from detecting it. Pay particu-
lar attention to the following obstacles.
• Wires, fences, ropes etc.
• Cotton, snow and other materials that absorb radio waves
• Sharply-angled objects
•Low obstacles
• Tall obstacles with upper sections projec ting outwards in the direction of your
vehicle
■When the display flashes and a message is displayed
 P. 5 0 4

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2-4. Using other driving systems
2
When driving
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.
■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 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.
■ TRAC (Traction Control)
Maintains drive power and prevents the rear wheels from spinning when
starting the vehicle or accelerating on slippery roads.
■Hill-start assist control
 P. 225
■EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.

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2-4. Using other driving systems
When the VSC/TRAC systems are operatingThe slip indicator light flashes to
indicate that the VSC/TRAC sys-
tems have been engaged.
■VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, TRAC, VSC, and
EPS systems.
Helps to maintain vehicle stability when swerving on slippery road sur-
faces by controlling the brakes, engine output and steering assist.
■PCS (Pre-Collision System) (if equipped)
 P. 2 2 7

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2-4. Using other driving systems
2
When driving
Hill-start assist control
■Hill-start assist control can be operated when
●The shift lever is in a position other than P (vehicles with automatic transmis-
sion).
●The parking brake is not applied.
●The accelerator pedal is not depressed.
■Hill-start assist control
●While hill-start assist control is operating, the brakes remain automatically
applied after the driver releases the brake pedal. The stop lights and the high
mounted stoplight turn on.
●Hill-start assist control operates for about 2 seconds after the brake pedal is
released.
●If the slip indicator does not flash and the buzzer does not sound when the brake
pedal is further depressed, slightly redu ce the pressure on the brake pedal (do
not allow the vehicle to roll backward) and then firmly depress it again. If the sys-
tem still does not operate, check if th e operating conditions explained above
have been met.
Hill-start assist control helps to prevent the vehicle from rolling backwards
when starting on an incline or slippery slope.
To engage hill-start assist con-
trol, further depress the brake
pedal when the vehicle is
stopped completely.
A buzzer will sound once to
indicate the system is activated.
The slip indicator will also start
flashing.

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2-4. Using other driving systems
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When driving
PCS (Pre-Collision System)
When the radar sensor detects possibility of a frontal collision, the pre-col-
lision systems such as the brakes and seat belts are automatically engaged
in an attempt to lessen damage.
■ Pre-collision seat belts
If the pre-collision sensor detects that a collision is unavoidable, the pre-
collision system will retract the seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses
control of the vehicle. ( P. 7 2 )
However, the system will not operate in the event of skidding when the
VSC systems are disabled.
■ Pre-collision brake assist
When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to how strongly the brake pedal is
depressed.
■Pre-collision braking
When there is a high possibility of a frontal collision, the system warns the
driver using a warning light, warnin g display and buzzer. If the system
determines that a collision is unavoidable, the brakes are automatically
applied to reduce the collision speed. The pre-collision braking function
can be turned on and off using the satellite switch.

: If equipped