2012 Lexus GS250 sensor

3234-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Guide lines are not dis-
playedThe trunk lid is open.
Close the trunk lid.
If this does not resolve
the symptom, have the
vehicle inspected by
any authorized Lexus
dealer or repairer, or
another duly qualified
and equipped profes-
sional.
“System is initializ-
ing.” is displayed
• The battery has been
reinstalled.
• The steering wheel
has been moved
while the battery was
being reinstalled.
• Battery power is low.
• The steering sensor
has been reinstalled.
• There is a malfunc-
tion in the signals
being output by the
steering sensor.
Stop the vehicle, and
turn the steering wheel
as far as it will go to
the left and right.
If this does not resolve
the symptom, have the
vehicle inspected by
any authorized Lexus
dealer or repairer, or
another duly qualified
and equipped profes-
sional.
• On the system initial-
ization screen, select
the “?” button to dis-
play the operating
procedure.
SymptomLikely causeSolution

3434-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
PCS (Pre-Crash Safety system)
Pre-crash seat belts (front seat only)
If the pre-crash sensor detects that a collision is unavoidable, the
pre-crash safety system will retract the seat belt before the colli-
sion occurs.
The same will happen if the driver makes an emergency braking
or loses control of the vehicle. (P. 40)
Pre-crash 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-crash braking
When there is a high possibility of a frontal collision, the system
warns the driver using a warning light, warning display and
buzzer. If the system determines that a collision is unavoidable,
the brakes are automatically applied to reduce the collision
speed.

: If equipped
When the radar sensor detects that a frontal collision is highly
likely or even unavoidable, safety systems such as the brakes and
seat belts are automatically engaged to lessen impact as well as
vehicle damage.
The pre-crash safety system can be turned on and off as necessary
by operating the switch. (P. 344)

3454-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)The radar sensor detects vehicles
or other obstacles on or near the
road ahead and determines
whether a collision is imminent
based on the position, speed, and
heading of the obstacles.
The driver monitor sensor
detects the direction the driver is
facing and whether the driver’s
eyes are open or closed.
The system determines whether
the driver is facing forward and
whether or not the driver’s eyes
are closed.
Radar sensor
Driver monitor sensor (if equipped)

3474-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Pre-crash alert braking:
• The system determines that the driver is not facing forward, or that the
driver’s eyes are closed.
• Vehicle speed is greater than about 40 km/h (25 mph).
• The speed at which your vehicle is approaching the vehicle running
ahead of you is greater than about 40 km/h (25 mph).
• The steering is not being turned.
Conditions that may trigger the system even if there is no danger of a 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 (left-hand drive vehicles)
or right-turn (right-hand drive vehicles)
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 climbing a steep hill causes an overhead billboard or other metallic
structure to appear directly in the vehicle’s line of travel
When the system is activated in the situations described above, there is also a
possibility 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 it.
Obstacles not detected
The sensor cannot detect plastic obstacles such as traffic cones. There may
also be occasions when the sensor cannot detect pedestrians, animals, bicy-
cles, motorcycles, trees, or snowdrifts.

3484-5. Using the driving support
GS350/250_EE (OM30C36E)
Situations in which the pre-crash safety 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 intersec-
tion
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
When your vehicle is skidding such as the VSC system off
When your vehicle is steeply inclined
Automatic cancelation of the pre-crash safety system
When a malfunction occurs due to sensor contamination, etc. that results in
the sensors being unable to detect obstacles, the pre-crash safety system 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
“PCS” warning light will flash and warning messages will be displayed.
(P. 751, 759)

3514-5. Using the driving support
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Driving
GS350/250_EE (OM30C36E)
CAUTION
Limitations of the pre-crash safety system
Do not overly rely on the pre-crash safety system. Always drive safely, tak-
ing 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.
Handling the radar sensor
Observe the following to ensure the pre-crash safety 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 malfunc-
tion. If the sensor or surrounding area is subject to a strong impact, always
have the area inspected and adjusted by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
Do not disassemble the sensor.
Do not attach accessories or stickers to the sensor, grille cover or sur-
rounding area.
Do not modify or paint the sensor and grille cover.
Do not replace them with non-genuine parts.
Determining the direction the driver is facing and whether the driver’s eyes
are open or closed
The direction the driver is facing and whether the driver’s eyes are open or
closed may not be determined correctly if the following conditions exist:
There is an object between the driver monitor sensor and the driver’s face,
such as when the sensor is blocked.
A part of the driver’s face is covered.
The sensor or the driver’s face is exposed to intense light such as sunlight.
The driving posture is improper.

3524-5. Using the driving support
GS350/250_EE (OM30C36E)
CAUTION
Handling the driver monitor sensor
Observe the following to ensure the driver monitor sensor can function
effectively.
Failure to do so may result in a malfunction or may prevent the system
from correctly determining the direction the driver is facing, resulting in an
unexpected accident.
Do not disassemble, damage, lift or pull on the sensor.
Do not touch the sensor while driving.
Do not wet or spill water on the sensor.
Do not drop anything on or allow anything to hit against the sensor. Do
not subject the sensor to an impact.
Make sure that there are no scratches, dirt or stickers on the side of the
sensor that faces the driver.
Do not place any objects in front of the side of the sensor that faces the
driver or cover the sensor.

3534-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
CAUTION
Cautions regarding the assist contents of the system
By means of alarms and brake control, the pre-crash safety 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 sys-
tem can provide, so please keep in mind the following important points.
Assisting the driver in watching the road
The pre-crash safety 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-visibility conditions. It is still necessary for the
driver to pay close attention to the vehicle’s surroundings.
Assisting the driver in making correct judgment
When attempting to estimate the likelihood of a collision, the only data
available to the pre-crash safety system is that from obstacles it has
detected directly in front of the vehicle. Therefore, it is absolutely neces-
sary for the driver to remain vigilant and to determine whether or not there
is a possibility of collision in any given situation.
Assisting the driver in taking action
The pre-crash safety 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 collision or bringing the vehicle 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.
NOTICE
Precautions for cleaning the driver monitor sensor
Gently wipe the sensor with a soft cloth to prevent damage.
Wipe any excess dirt with a cloth dampened with neutral detergent, all liq-
uids having been wringed out of the cloth. After that, wipe again with a
dry cloth.
Do not use benzene, thinner, glass cleaners, wax, etc.