2012 Lexus GS250 lane assist

2674-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Automatic cancelation of constant speed control
The cruise control will stop maintaining the vehicle speed in the following
situations:
Actual vehicle speed is more than approximately 16 km/h (10 mph) below
the set vehicle speed.
At this time, the memorized set speed is not retained.
Vehicle speed falls below approximately 40 km/h (25 mph).
VSC is activated.
TRC is activated for a period of time.
When the VSC or TRC system is turned off by pressing the VSC OFF
switch.
When the LKA (Lane-Keeping Assist) will be activated
Using the radar cruise control in vehicle-to-vehicle distance control mode,
lane keeping assistance control is activated.
Radar sensor and grille cover
Always keep the sensor and grille cover clean to ensure that the vehicle-to-
vehicle distance control operates properly. (Some obstructions, such as snow,
ice and plastic objects, cannot be detected by the obstruction sensor.)
Dynamic radar cruise control is canceled if an obstruction is detected.
Warning messages and buzzers for dynamic radar cruise control
Warning messages and buzzers are used to indicate a system malfunction or
to inform the driver of the need for caution while driving. (P. 760) Grille cover
Radar sensor
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2744-5. Using the driving support
GS350/250_EE (OM30C36E)
LKA (Lane-Keeping Assist)
While driving on a freeway or motor highway that has lane markers
and no sharp curves, the system recognizes the lanes using a cam-
era located above the inside rear view mirror as a sensor to assist
the driver with staying in the lane. The LKA system has two func-
tions.
Camera sensor

: If equipped
Summary of functions

2754-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)Lane departure warning function
If the system judges that the vehicle may deviate from its lane, it
alerts the driver using beeping, screen displays and a sensory
warning
* given via the steering wheel.
*: A slight steering torque is applied for a short period of time in the direc-
tion of the center of the lane.
Lane keeping assist function
• This function will be active when the vehicle-to-vehicle dis-
tance control mode of the cruise control (P. 258) is set with
vehicle speed above approximately 72 km/h (45 mph) and
while the lane departure warning function is active.
• When the lane keeping assist function is active, a slight steer-
ing torque will be applied, to help the driver maintain the vehi-
cle inside the lane.
The lane keeping assist function will be temporarily canceled if the
steering wheel is not operated, or if you continue driving with your
hands lightly touching the steering wheel. (P. 279)
Functions included in the LKA
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2774-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Lane departure warning function
When the vehicle speed is approximately 48 km/h (30 mph) or
more
When the lane width is more than approximately 2.8 m (9.1
ft.)
When driving on a straight road or through a curve with a
radius of more than approximately 120 m (394 ft.)
Lane keeping assist function
When the vehicle speed is between approximately 72 and 180 km/
h (45 and 112 mph)
When the vehicle-to-vehicle distance mode of the radar cruise
control is on, and the set vehicle speed is approximately 72
km/h (45 mph) or more (the function will not operate when the
radar cruise control is in set speed mode)
When the lane width is between approximately 2.8 and 4.0 m
(9.1 and 13.1 ft.)
When driving on a straight road or through a curve with a
radius of more than approximately 230 m (755 ft.)
Operating conditions for each function

2784-5. Using the driving support
GS350/250_EE (OM30C36E)When the LKA system is on, the lane line display and steering
wheel display are shown.
Lane keeping assist function
operation indication
Steering wheel displayed:
Indicates that the function is cur-
rently operating. (If the lane depar-
ture warning operates at this time,
the steering wheel flashes orange.)
Steering wheel not displayed:
Indicates that the function is not
currently operating. (When the
lane keeping assist function is can-
celed, the buzzer will beep twice.)
Dynamic radar cruise control
display
Lane departure warning func-
tion indication (when the
inside of the white line is
white):
The function has recognized lane
markers. (If the lane departure
warning operates at this time, the
lines flash orange.)
Lane departure warning func-
tion indication (when the
inside of the white line is
black):
A lane marker is not recognized by
the system, or the LKA system
functions are temporarily canceled.
Indication on the multi-information display
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2794-5. Using the driving support
4
Driving
GS350/250_EE (OM30C36E)
Temporary cancelation of the LKA system functions
If any of the following occurs, the LKA system functions will be temporarily
canceled. The functions will resume after the necessary operating conditions
have returned.
The steering wheel is turned as far as necessary to cause the vehicle to
change lanes.
When the system detects no-handed driving. (The lane keeping assist func-
tion will be temporarily canceled, but the lane departure warning function
will continue.)
The turn signal lever is operated.
The vehicle speed deviates from the operating range of the LKA system
functions. (The buzzer will beep twice when the lane keeping assist func-
tion is being canceled.)
When the lane lines cannot be recognized while driving. (The buzzer will
beep twice when the lane keeping assist function is being canceled.)
The wiper switch is set on high speed mode or is set on AUTO mode with
wipers operating at high speed. (The lane keeping assist function will be
temporarily canceled, but the lane departure warning function will con-
tinue.)
If the vehicle crosses a line for approximately half a minute or more. (The
lane keeping assist function will be temporarily canceled, but the lane
departure warning function will continue.)
When the lane departure warning function is activated.
The lane departure warning function will not operate again for a several
seconds after it has been activated, even if the vehicle leaves the lane again.
The lane departure warning
It may be difficult to feel the sensory warning depending on the road condi-
tions.
No-handed driving warning
If the steering wheel is not operated for approximately 15 seconds on a
straight road or approximately 5 seconds on a curve, the buzzer will beep
twice, indicators on the multi-information display will flash, and the lane
keeping assist function will be temporarily canceled. If you drive the vehicle
with your hands lightly touching the steering wheel, this may also be
detected as no-handed driving.

2804-5. Using the driving support
GS350/250_EE (OM30C36E)
After the vehicle has been parked in the sun
The LKA system functions may not be available and a warning message
(P. 767) will be displayed for a while after driving has started. In such
cases, turn the LKA system off and turn it on again after normal temperature
returns. When the temperature in the cabin decreases and the temperature
around the camera sensor (P. 274) becomes suitable for its operation, the
functions will begin to operate.
If there are lane markers on only one side of the vehicle
The lane keeping assist function will not operate. Also, the lane departure
warning will not operate for the side on which lane markers could not be rec-
ognized.
Conditions in which the function may not operate correctly
In the following conditions, the LKA system functions may not operate, or it
may not be possible to ensure adequate performance. Also, the camera sensor
may be unable to recognize lane lines causing the lane departure warning
function to operate incorrectly, or the lane keeping assist function may not
operate properly. However, this does not indicate a malfunction.
When driving through an area with no lane markers, such as a tollbooth, a
crossing or before a ticket checkpoint
When driving on a sharp curve
When lanes are extremely narrow or extremely wide
When the vehicle leans to one side an unusual amount due to a heavy load
or improper tire inflation pressure
When the following distance between your vehicle and the vehicle ahead is
extremely short
When the lane markers are yellow (These may be more difficult for the sys-
tem to recognize compared to white markers.)
When the lane markers are broken, “Raised pavement marker” or stones
When lane markers are obscured or partially obscured by sand, dirt, etc.
When there are shadows on the road running parallel with lane markers, or
if a shadow covers the lane markers
When driving on a particularly bright road surface, such as concrete
When driving on a road surface that is bright due to reflected light
When driving in a location where the light level changes rapidly, such as the
entrance to or exit from a tunnel
When sunlight or the headlights of oncoming vehicles are shining directly
into the camera lens

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.