Lexus GS350 2013 Using the driving support systems / LEXUS 2013 GS350 OWNERS MANUAL (OM30C34U)

GS350_U (OM30C34U)
2714-5. Using the driving support systems
4
Driving
■Turning off both TRAC/VSC systems
To turn the TRAC/VSC systems
off, press and hold the button for
more than 3 seconds while the
vehicle is stopped.
The VSC OFF indicator light will
come on and the “TRAC OFF” will
be shown on the multi-information
display.
Press the button again to turn the
systems back on.

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GS350_U (OM30C34U)
4-5. Using the driving support systems
■When the message is displayed on the multi-information display showing that
TRAC has been disabled even if the VSC OFF switch has not been pressed
TRAC cannot be operated. Contact your Lexus dealer.
■VGRS is disabled when
VGRS may stop operating in the following situations.
In this event, the steering wheel may move from its straight forward position, but it
will return when the system restarts.
●The steering wheel is operated for an extended period of time while the vehicle is
stopped or is moving very slowly.
●When force is continuously applied for a long time with the steering wheel turned
as far as it will go.
The center position of the steering wheel may change when VGRS is disabled. How-
ever, the position will return to normal after VGRS is reactivated.
■When the battery is disconnected
The steering wheel may move from its straight forward position, but this will be cor-
rected automatically when driving.
■Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and VGRS 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 malfunc-
tion 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, VGRS and DRS 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 TRAC/VSC systems
Even after the TRAC/VSC systems have been turned off, turning the engine off and
then on again will automatically reactivate the TRAC/VSC systems.

GS350_U (OM30C34U)
2734-5. Using the driving support systems
4
Driving
■Reactivation of the TRAC system linked to vehicle speed
When only the TRAC system is turned off, the TRAC system will turn on when vehi-
cle speed increases. However, when both TRAC/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 overheat-
ing when there is frequent steering input ov er an extended period of time. The steer-
ing 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.

274
GS350_U (OM30C34U)
4-5. Using the driving support systems
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 condi-
tions
The ABS is not designed to shorten the ve hicle’s stopping distance. Always main-
tain 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
■TRAC may not operate effectively when
Directional control and power may not be achievable while driving on slippery
road surfaces, even if the TRAC 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 TRAC/VSC systems are turned off
Be especially careful and drive at a spee d appropriate to the road conditions. As
these are the systems to ensure vehicle stability and driving force, do not turn the
TRAC/VSC systems off unless necessary.

GS350_U (OM30C34U)
2754-5. Using the driving support systems
4
Driving
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, TRAC and VSC systems will not function correctly if different tires are
installed on the vehicle.
Contact your Lexus dealer 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.

276
GS350_U (OM30C34U)
4-5. Using the driving support systems
Hill-start assist control
To engage hill-start assist control,
further depress the brake pedal
when the vehicle is stopped com-
pletely.
A buzzer will sound once to indicate
the system is activated. The slip indica-
tor will also start flashing.
■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 peda l is not depressed.
●Hill-start assist control cannot be operated while the slip indicator light is illumi-
nated.
■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 conditions 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.

GS350_U (OM30C34U)
2774-5. Using the driving support systems
4
Driving
■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 ofreleasing 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 fo r more than approximately 3 minutes.
■If the slip indicator comes on
It may indicate a malfunction in the system. Contact your Lexus dealer.
CAUTION
■Hill-start assist control
●Do not overly rely on hill-start assist control. Hill-start assist control may not oper-
ate effectively on steep inclines and roads covered with ice.
●Unlike the parking brake, hill-start assist control is not intended to hold the vehi-
cle stationary for an extended period of time. Do not attempt to use hill-start
assist control to hold the vehicle on an in cline, as doing so may lead to an acci-
dent.

278
GS350_U (OM30C34U)
4-5. Using the driving support systems
PCS (Pre-Collision System)
◆Pre-collision seat belts (front seat only)
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 dr iver makes an emergency braking or
loses control of the vehicle. ( P. 32)
◆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 poss ibility of a frontal collision, the system warns
the driver using a warning light, war ning display and buzzer. If the sys-
tem determines that a collision is unavoidable, the brakes are automati-
cally 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-collision system ca n be turned on and off as necessary by oper-
ating the switch. ( P. 280)

GS350_U (OM30C34U)
2794-5. Using the driving support systems
4
Driving
◆Suspension control (if equipped)
When the system determines that a collision is unavoidable, the opera-
tion of AVS ( P. 269) optimally controls the damping force of the
shock absorber.
◆Steering control (if equipped)
Vehicles with VGRS
There is a high possibility of collisi on and if the steering wheel is oper-
ated, the steering gear ratio is chan ged by VGRS to help improve the
response to steering input.
Vehicles with LDH
There is a high possibility of collisi on and if the steering wheel is oper-
ated, the steering angles of the fr ont and rear wheels and the heaviness
of the steering wheel are controlled by LDH, thus heightening respon-
siveness in response to the steering operation.
◆Driver monitor system (if equipped)
When the system determines that there is a possibility of a collision, and
either the driver is not facing forwar d 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-collision alert braking
have been met even when the possibility of a collision increases further,
pre-collision alert braking will operate.

280
GS350_U (OM30C34U)
4-5. Using the driving support systems
Enabled
Disabled
The “PCS” warning light comes on
when pre-collision system is disabled.
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.
Disabling pre-collision system
1
2
Radar sensor
Driver monitor sensor (if equipped)