2012 Lexus IS250C brake

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2-4. Using other driving systems
2
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

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2-4. Using other driving systems
Disabling the pre-collision brakingThe pre-collision braking function
can be turned on and off using the
satellite switch. (P. 371)
Press “ ”or “ ” to display the PCS
brake setting ( ). Then, press the
“ON/OFF” button in the middle of
the switch to select either “ON” or
“OFF” ( ).
It may take approximately 3 sec-
onds for the display to change after
the satellite switch is operated.
The “PCS” warning light flashes
when “OFF” is selected.
Radar sensor
Detects vehicles or other obsta-
cles on or near the road ahead and
determines whether a collision is
imminent based on the position,
speed, and heading of the obsta-
cles. Grille cover
Radar sensor
■Obstacles not detected
The sensor cannot detect plastic obstacles such as pylons. There may also be occa-
sions when the sensor cannot detect pedestrians, animals, bicycles, motorcycles,
trees, or snowdrifts.

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2-4. Using other driving systems
2
When driving
■The pre-collision system is operational when
●Pre-collision seat belt (type A)
• Vehicle speed is above 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncomingvehicle exceeds 19 to 25 mph (30 to 40 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (type B)
• Vehicle speed exceeds 19 mph (30 km/h).
• The system detects sudd en braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision brake Assist
• Vehicle speed is above 19 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle is greater than 19 to 25 mph (30 to 40 km/h).
• The brake pedal is depressed.
●Pre-collision braking:
• The pre-collision braking function is activated.
• Vehicle speed is above 10 mph (1 5 km/h).
• The relative speed difference between your vehicle and another vehicle that is forward of your vehicle, or the speed at which your vehicle is approaching
an obstacle is greater than 10 mph (1 5 km/h).
■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 be nds 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 heav y rain, fog, snow or sand storms
●When your vehicle is skidding with the VSC system off
●When an extreme change in vehicle height occurs
●When the axis of the radar is out of adjustment

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2-4. Using other driving systems
■ Conditions that may trigger the system even if there is no possibility of collision
●When there is an object by the roadside at the entrance to a curve
●When passing an oncoming vehicle on a curve
●When driving over a narrow iron bridge
●When there is a metal object on the road surface
●When driving on an uneven road surface
●When passing an oncoming vehicle on a left-turn
●When your vehicle rapidly closes on the vehicle in front
●When a grade separation/interchange, sign, billboard, or other structure
appears to be directly in the vehicle’s line of travel.
●When an overhead billboard or other me tallic structure appears to be in the
vehicle’s direct line of travel due to driving on a hill.
●When an extreme change in vehicle height occurs
●When the axis of the radar is out of adjustment
●When passing through certain toll gates
●When driving on a bridge.
When the system is activated in the situations described above there is also a possi-
bility that the seat belts will retract quickly and the brakes will be applied with a force
greater than normal. When the seat belt is locked in the retracted position, stop the
vehicle in a safe place, release the seat belt and refasten.
■Automatic cancelation of the pre-collision system
When a malfunction occurs due to sensor contamination, etc. that results in the
sensors being unable to detect obstacles, the pre-collision system will be automati-
cally disabled. In this case, the system will not activate even if there is a collision pos-
sibility.
■When there is a malfunction in the system
Warning lights and/or warning messages will turn on or flash. ( P. 495, 504)

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2-4. Using other driving systems
CAUTION
■Limitations of the pre-collision system
Do not rely on the pre-collision system. Always drive safely, taking care to observe
your surroundings and checking for any obstacles or other road hazards.
Failure to do so may cause an accident resulting in death or serious injury.
■Cautions regarding the assist contents of the system
By means of alarms and brake control, the pre-collision system is intended to assist
the driver in avoiding collisions through the process of LOOK-JUDGE-ACT. There
are limits to the degree of assistance the system can provide, so please keep in mind
the following important points.
●Assisting the driver in watching the road
The pre-collision system is only able to detect obstacles directly in front of the
vehicle, and only within a limited range. It is not a mechanism that allows careless
or inattentive driving, and it is not a system that can assist the driver in low-visibil-
ity conditions. It is still necessary for the driver to pay close attention to the vehi-
cle’s surroundings.
●Assisting the driver in making correct judgment
When attempting to estimate the possibilit y of a collision, the only data available
to the pre-collision system is that from ob stacles it has detected directly in front of
the vehicle. Therefore, it is absolutely necessary for the driver to remain vigilant
and to determine whether or not there is a possibility of collision in any given situ-
ation.
●Assisting the driver in taking action
The pre-collision system’s braking assist feature is designed to help reduce the
severity of a collision, and so only acts when the system has judged that a collision
is unavoidable. This system by itself is not capable of automatically avoiding a col-
lision or bringing the vehicl e to a stop safely. For this reason, when encountering a
dangerous situation the driver must take direct and immediate action in order to
ensure the safety of all involved.

236
2-5. Driving information
CAUTION
■Things that must not be carried in the trunk
The following things may cause a fire if loaded in the trunk.
●Receptacles containing gasoline
●Aerosol cans
■Storage precautions
Observe the following precautions.
Failing to do so may result in death or serious injury.
●Do not place cargo or luggage in or on the following locations as the item may
get under the clutch, brake or accelerator pedal and prevent the pedals from
being depressed properly, block the driver’s vision, or hit the driver or passen-
gers, causing an accident.
• At the feet of the driver
• On the front passenger or rear seats (when stacking items)
• On the package tray
• On the instrument panel
•On the dashboard
●Secure all items in the occupant compartment, as they may shift and injure some-
one during sudden braking, sudd en swerving or an accident.
■Capacity and distribution
●Do not exceed the maximum axle weight ra ting or the total vehicle weight rating.
●Even if the total load of occupant's weight and the cargo load is less than the total
load capacity, do not apply the load unevenly. Improper loading may cause dete-
rioration of steering or braking control which may cause death or serious injury.

238
2-5. Driving information
Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■ Pre-winter preparations
●Use fluids that are appropria te to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific gravity of
battery electrolyte.
● 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 the same brand, and that
chains match the size of the tires.
■ Before driving the vehicle
Perform the following according to the driving conditions.
● Do not try to forcibly open a w indow or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To ensure proper operation of the climate control system fan,
remove any snow that has accumu lated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumul ated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.

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2-5. Driving information
2
When driving
Selecting tire chainsThey cannot be mounted on 18-inch ti res. Use the correct tire chain size
when mounting the tire chains. Chain size is regulated for each tire sizes.
Side chain
(0.12 in. [3 mm] in diameter)
Cross chain
(0.16 in. [4 mm] in diameter)
Regulations on the use of tire chains
● Regulations regarding the use of tire chains vary according to location
and type of road. Always check local regulations before installing
chains.
● Install the chains on the rear tires.
● Retighten the chains after driving 1 /4  1 /2 mile (0.5  1.0 km).
■When driving the vehicle
Accelerate the vehicle slowly and dr ive at a reduced speed suitable
to road conditions.
■ When parking the vehicle (in the winter time or in the cold lati-
tudes)
Park the vehicle and move the shift lever to P (automatic transmis-
sion) or 1 or R (manual transmission) and block the wheel under the
vehicle without setting the parking brake. The parking brake may
freeze up, preventing it from being released. If necessary, block the
wheels to prevent inadvertent sliding or creeping.