2012 Lexus GS350 Owner's Manual

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.

339
4 4-5. Using the driving support
Driving
GS350/250_EE (OM30C36E)
CAUTION
The ABS does not operate effectively when
Tires with inadequate gripping ability are used (such as excessively worn
tires on a snow covered road).
The vehicle hydroplanes while driving at high speed on wet or slick roads.
Stopping distance when the ABS is operating may exceed that of normal
conditions
The ABS is not designed to shorten the vehicle’s stopping distance. Always
maintain a safe distance from the vehicle in front of you in the following
situations:
When driving on dirt, gravel or snow-covered roads
When driving with tire chains
When driving over bumps in the road
When driving over roads with potholes or uneven surfaces
TRC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRC system is operating.
Do not drive the vehicle in conditions where stability and power may be
lost.
When the VSC is activated
The slip indicator light flashes. Always drive carefully. Reckless driving
may cause an accident. Exercise particular care when the indicator light
flashes.
When the TRC/VSC systems are turned off
Be especially careful and drive at a speed appropriate to the road condi-
tions. As these are the systems to ensure vehicle stability and driving force,
do not turn the TRC/VSC systems off unless necessary.

3404-5. Using the driving support
GS350/250_EE (OM30C36E)
CAUTION
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 inflation pressure level.
The ABS, TRC and VSC systems will not function correctly if different
tires are installed on the vehicle.
Contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional for further information when replacing tires or
wheels.
Handling of tires and the suspension
Using tires with any kind of problem or modifying the suspension will
affect the driving assist systems, and may cause a system to malfunction.

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.

3424-5. Using the driving support
GS350/250_EE (OM30C36E)
Hill-start assist control buzzer
When hill-start assist control is activated, the buzzer will sound once.
In the following situations, hill-start assist control will be canceled and the
buzzer will sound twice.
• No attempt is made to drive the vehicle within approximately 2 seconds
of releasing the brake pedal.
• The shift lever is moved to P.
• The parking brake is applied.
• The brake pedal is depressed again.
• The brake pedal has been depressed for more than approximately 3 min-
utes.
If the slip indicator comes on
It may indicate a malfunction in the system. Contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
CAUTION
Hill-start assist control
Do not overly rely on hill-start assist control. Hill-start assist control may
not operate effectively on steep inclines and roads covered with ice.
Unlike the parking brake, hill-start assist control is not intended to hold
the vehicle stationary for an extended period of time. Do not attempt to
use hill-start assist control to hold the vehicle on an incline, as doing so
may lead to an accident.

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)

3444-5. Using the driving support
GS350/250_EE (OM30C36E)
Suspension control (if equipped)
When the system determines that a collision is unavoidable, the
operation of AVS (P. 334) optimally controls the damping
force of the shock absorber.
Driver monitor system (if equipped)
When the system determines that there is a possibility of a colli-
sion, and either the driver is not facing forward or the driver’s
eyes are closed, PCS warnings are given in advance to warn the
driver. If the system determines that the conditions to operate
pre-crash alert braking have been met even when the possibility
of a collision increases further, pre-crash alert braking will oper-
ate.
Enabled
Disabled
The “PCS” warning light comes on
when pre-crash safety system is
disabled.
Disabling pre-crash safety system
1
2

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)