2012 Lexus GS250 AUTO

3334-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Driving assist systems
ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied sud-
denly, 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
VSC+ (Vehicle Stability Control+)
Provides cooperative control of the ABS, TRC, VSC and EPS.
Helps to maintain directional stability when swerving on slippery
road surfaces by controlling steering performance.
TRC (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
P. 341
To help enhance driving safety and performance, the following
systems operate automatically in response to various driving situa-
tions. Be aware, however, that these systems are supplementary
and should not be relied upon too heavily when operating the vehi-
cle.

3344-5. Using the driving support
GS350/250_EE (OM30C36E)
EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed
to turn the steering wheel
AVS (Adaptive Variable Suspension system) (if equipped)
By independently controlling the damping force of the shock
absorbers for each of the 4 wheels according to the road and driv-
ing conditions, this system combines riding comfort with supe-
rior steering stability, and ensures good vehicle posture. (P.
328)
VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, TRC, VSC,
hill-start assist control and EPS systems
Helps to maintain vehicle stability when swerving on slippery
road surfaces by controlling the brakes, engine output, steering
assist, and steering ratio
PCS (Pre-Crash Safety system) (if equipped)
P. 343
Emergency brake signal
When the brakes are applied suddenly, the stop lights automati-
cally flash to alert the vehicle behind.

3374-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
When the message is displayed on the multi-information display showing that
TRC has been disabled even if the VSC OFF switch has not been pressed
TRC cannot be operated. Contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
Sounds and vibrations caused by the ABS, brake assist, VSC and TRC sys-
tems
A sound may be heard from the engine compartment 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
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 slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.
EPS 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 TRC/VSC systems
Even after the TRC/VSC systems have been turned off, turning the engine
off and then on again will automatically reactivate the TRC/VSC systems.

3384-5. Using the driving support
GS350/250_EE (OM30C36E)
Reactivation of the TRC system linked to vehicle speed
When only the TRC system is turned off, the TRC system will turn on when
vehicle speed increases. However, when both TRC and 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
off. The effectiveness will improve after a short while.
*: If the LKA (Lane-Keeping Assist) system cannot operate in this case, a
warning message will be shown on the multi-information display.
Operating conditions of emergency brake signal
When the following three conditions are met, the emergency brake signal
will operate:
The emergency flashers are off.
Actual vehicle speed is over 55 km/h (35 mph).
The brake pedal is depressed in a manner that cause the system to judge
from the vehicle deceleration that this is a sudden braking operation.
Automatic system cancelation of emergency brake signal
The emergency brake signal will turn off in any of the following situations:
The emergency flashers are turned on.
The brake pedal is released.
The system judges from the vehicle deceleration that is not a sudden brak-
ing operation.

341
4 4-5. Using the driving support
Driving
GS350/250_EE (OM30C36E)
Hill-start assist control
To engage hill-start assist con-
trol, further depress the brake
pedal when the vehicle is
stopped completely.
A buzzer will sound once to indi-
cate the system is activated. The
slip indicator will also start flash-
ing.
Hill-start assist control operating conditions
The system operates in the following situations:
• The shift lever is in a position other than P.
• The parking brake is not applied.
• The accelerator pedal is not depressed.
Hill-start assist control cannot be operated while the slip indicator light is
illuminated.
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 reduce the pressure on the brake
pedal (do not allow the vehicle to roll backward) and then firmly depress it
again. If the system still does not operate, check that the operating condi-
tions explained above have been met.
Assists with starting off and temporarily maintains braking power
even if the foot is removed from the brake pedal when starting off
on an incline or a slippery slope.

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)

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)

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.