warning Lexus GS300h 2015 Service Manual

2804-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
■If the PCS warning light flashes and a warning message is displayed on the multi-infor-
mation display
The pre-crash safety system may be temporarily unavailable or there may be a malfunc-
tion in the system.
●In the following situations, the warning light will turn off, the message will disappear and
the system will become operational when normal operating conditions return:
• When the radar sensor or camera sensor or the area around either sensor is hot, such as in the sun
• When the radar sensor or camera sensor or the area around either sensor is cold,
such as in an extremely cold environment
• When the radar sensor or front grille emblem is dirty or covered with snow, etc.
• If the camera sensor is obstructed, such as when the hood is open or a sticker is
attached to the windshield near the camera sensor
●If the PCS warning light continues to flash or the warning message does not disappear,
the system may be malfunctioning. Have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional immediately.
■If VSC is disabled
●If VSC is disabled ( →P. 347), the pre-crash brake assist and pre-crash braking func-
tions are also disabled.
●The PCS warning light will turn on and “VSC Turned Off Pre-Crash Brake System
Unavailable” will be displayed on the multi-information display.

281
4
4-5. Using the driving support systems
Driving
GS450h_300h_OM_OM30F00E_(EE)
LKA (Lane-Keeping Assist)∗
When driving on highways and freeways with white or yellow lines, this function
alerts the driver when the vehicle might depart from its lane and provides assis-
tance by operating the steering wheel to keep the vehicle in its lane. Further-
more, the system also provides steering assistance when dynamic radar cruise
control with full-speed range is operating to keep the vehicle in its lane.
The LKA system recognizes visible
white or yellow lines with the camera
sensor on the upper portion of the front
windshield.
◆Lane departure alert function
When the system determines that
the vehicle might depart from its
lane, a warning is displayed on the
multi-information display, and either
the warning buzzer sounds or the
steering wheel vibrates to alert the
driver.
When the warning buzzer sounds or
the steering wheel vibrates, check
the surrounding road situation and
carefully operate the steering wheel
to move the vehicle back to the cen-
ter within the white (yellow) lines.
∗: If equipped
Summary of functions
Functions included in LKA system

2824-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
◆Lane departure control function
When the system determines that
the vehicle might depart from its
lane, the system provides assistance
as necessary by operating the steer-
ing wheel in small amounts for a
short period of time to keep the
vehicle in its lane.
If the system detects that the steering
wheel has not been operated for a
fixed amount of time or the steering
wheel is not being firmly gripped, a
warning is displayed on the multi-
information display and the function
is temporarily canceled.
◆Ve h i c l e s w a y w a r n i n g
When the vehicle is swaying or
appears as if it may depart from its
lane multiple times, the warning
buzzer sounds and a message is dis-
played on the multi-information dis-
play to alert the driver.

2834-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
◆Lane centering function
This function is linked with radar
cruise control and provides the
required assistance by operating the
steering wheel to keep the vehicle in
its current lane.
When radar cruise control is not
operating, the lane centering func-
tion does not operate.
If the system detects that the steering
wheel has not been operated for a
fixed amount of time or the steering
wheel is not being firmly gripped, a
warning is displayed on the multi-
information display and the function
is temporarily canceled.

2874-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
●Ve h i c l e s w a y w a r n i n g
This function operates when all of the following conditions are met.
• Setting for “Sway Warning” in of the multi-information display is set to “On”.
( → P. 111)
• Vehicle speed is approximately 50 km/h (32 mph) or more.
• Width of traffic lane is approximately 3 m (9.8 ft.) or more.
• No system malfunctions are detected. ( →P. 2 8 9 )
●Lane centering function
This function operates when all of the following conditions are met.
• LKA is turned on.
• Setting for “Steering Assist” and “Lane Center” in of the multi-information
display are set to “On”. ( →P. 111)
•System recognizes wh ite (yellow) lines.
• Dynamic radar cruise control with full-speed range is operating.
• Width of traffic lane is approximately 2.5 to 4.1 m (8.2 to 13.5 ft.).
• Turn signal lever is not operated.
• Vehicle is driven on a straight road or around a gentle curve with a radius of more
than approximately 200 m (656 ft.).
• No system malfunctions are detected. ( →P. 2 8 9 )
• Vehicle does not accelerate or decelerate by a fixed amount or more.
• Steering wheel is not operated with a steering force level suitable for changing lanes.
• ABS, VSC, TRC and PCS (Pre-Crash Safety system) are not operating.
• TRC or VSC is not turned off.
• Hands off steering wheel alert ( →P. 288) is not displayed.
• Lane departure control function is not operating.
■Temporary cancellation of functions
When operation conditions are no longer met, a function may be temporarily canceled.
However, when the operation conditions are met again, operation of the function is auto-
matically restored. ( →P. 2 8 6 )
■Lane departure control function/lane centering function
Depending on the vehicle speed, lane departure situation, road conditions, etc., the
operation of the functions may not be reco gnized or the functions may not operate.
■Lane departure alert function
The warning buzzer may be difficult to hear due to external noise, audio playback, etc.
Also, it may be difficult to feel steering wheel vibrations due to the road conditions, etc.

2884-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
■Hands off steering wheel alert
When the system determines that the driver has removed their hands from the steering
wheel while the lane departure control function or lane centering function is operating, a
warning message is displayed on the multi-information display.
If the driver continues to keep their hands off of the steering wheel, the buzzer sounds, a
warning message is displayed and the function is temporarily canceled. This alert also
operates in the same way when the vehicle is driven with the steering wheel lightly
gripped. However, depending on the road conditions, etc., the function may not cancel.
■White (yellow) lines are only on one side of road
The LKA system will not operate for the side on which white (yellow) lines could not be
recognized.
■Conditions in which functi ons may not operate properly
In the following situations, the camera sensor may not detect white (yellow) lines and var-
ious functions may not operate normally.
●There are shadows on the road that run parallel with, or cover, the white (yellow) lines.
●The vehicle is driven in an area without white (yellow) lines, such as in front of a tollgate
or checkpoint, or at an intersection, etc.
●The white (yellow) lines are cracked, “Raised pavement marker” or stones are present.
●The white (yellow) lines cannot be seen or are difficult to see due to sand, etc.
●The vehicle is driven on a road surface that is wet due to rain, puddles, etc.
●The traffic lines are yellow (which may be more difficult to recognize than lines that are
white).
●The white (yellow) lines cross over a curb, etc.
●The vehicle is driven on a bright surface, such as concrete.
●The vehicle is driven on a surface that is bright due to reflected light, etc.
●The vehicle is driven in an area where the brightness changes suddenly, such as at the
entrances and exits of tunnels, etc.
●Light from the headlights of an oncoming vehicle, the sun, etc., enters the camera.
●The vehicle is driven where the road diverges, merges, etc.
●The vehicle is driven on a slope.
●The vehicle is driven on a road which t ilts left or right, or a winding road.
●The vehicle is driven on an unpaved or rough road.
●The vehicle is driven around a sharp curve.
●The traffic lane is excessively narrow or wide.
●The vehicle is extremely tilted due to carrying heavy luggage or having improper tire
pressure.
●The distance to the preceding vehicle is extremely short.
●The vehicle is moving up and down a large am ount due to road conditions during driv-
ing (poor roads or road seams).
●The headlight lenses are dirty and emit a faint amount of light at night, or the beam axis
has deviated.
●The vehicle is struck by a crosswind.
●The vehicle has just changed lanes or crossed an intersection.
●Snow tires, etc., are equipped.

2894-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
■Warning message
Warning messages are used to indicate a system malfunction or to inform the driver of
the need for caution while driving. ( →P. 4 8 2 )
■Customization
The following settings can be changed.
For how to change settings, refer to P. 581.
FunctionSetting details
Lane departure alert functionAdjust alert sensitivity
Adjust alert type
Steering control functionTurn steering wheel assistance on and off
Vehicle sway warningTurn function on and off
Adjust alert sensitivity
Lane centering functionTurn function on and off

2904-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
LDA (Lane Departure Alert with steering control)∗
When driving on highways and freeways with white (yellow) lines, this function
alerts the driver when the vehicle might depart from its lane and provides assis-
tance by operating the steering wheel to keep the vehicle in its lane.
The LDA system recognizes visible
white (yellow) lines with the camera
sensor on the upper portion of the front
windshield.
◆Lane departure alert function
When the system determines that
the vehicle might depart from its
lane, a warning is displayed on the
multi-information display, and either
the warning buzzer sounds or the
steering wheel vibrates to alert the
driver.
When the warning buzzer sounds or
the steering wheel vibrates, check
the surrounding road situation and
carefully operate the steering wheel
to move the vehicle back to the cen-
ter within the white (yellow) lines.
∗: If equipped
Summary of functions
Functions included in LDA system

2914-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
◆Steering control function
When the system determines that
the vehicle might depart from its
lane, the system provides assistance
as necessary by operating the steer-
ing wheel in small amounts for a
short period of time to keep the
vehicle in its lane.
Except for Israel: If the system
detects that the steering wheel has
not been operated for a fixed amount
of time or the steering wheel is not
being firmly gripped, a warning is dis-
played on the multi-information dis-
play and the function is temporarily
canceled.
For Israel: If the system detects that
the steering wheel has not been
operated for a fixed amount of time
or the steering wheel is not being
firmly gripped, a warning is displayed
on the multi-information display and
the warning buzzer sounds.
◆Ve h i c l e s w a y w a r n i n g
When the vehicle is swaying or
appears as if it may depart from its
lane multiple times, the warning
buzzer sounds and a message is dis-
played on the multi-information dis-
play to alert the driver.

2954-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
●Ve h i c l e s w a y w a r n i n g
This function operates when all of the following conditions are met.
• Setting for “Sway Warning” in of the multi-information display is set to “On”.
( → P. 111)
• Vehicle speed is approximately 50 km/h (32 mph) or more.
• Width of traffic lane is approximately 3 m (9.8 ft.) or more.
• No system malfunctions are detected. ( →P. 2 9 7 )
■Temporary cancellation of functions
When operation conditions are no longer met, a function may be temporarily canceled.
However, when the operation conditions are met again, operation of the function is auto-
matically restored. ( →P. 2 9 4 )
■Steering control function
Depending on the vehicle speed, lane departure situation, road conditions, etc., the
operation of the functions may not be reco gnized or the functions may not operate.
■Lane departure alert function
The warning buzzer may be difficult to hear due to external noise, audio playback, etc.
Also, it may be difficult to feel steering wheel vibrations due to the road conditions, etc.
■Hands off steering wheel alert
Except for Israel: When the system determines that the driver has removed their hands
from the steering wheel while the steering co ntrol function is operating, a warning mes-
sage is displayed on the multi-information display.
If the driver continues to keep their hands off of the steering wheel, the buzzer sounds, a
warning message is displayed and the function is temporarily canceled. This alert also
operates in the same way when the vehicle is driven with the steering wheel lightly
gripped. However, depending on the road conditions, etc., the function may not cancel.
For Israel: When the system determines that the driver has removed their hands from the
steering wheel while the lane departure control function or lane centering function is
operating, a warning message is displayed on the multi-information display and the
buzzer sounds.
■White (yellow) lines are only on one side of road
The LDA system will not operate for the side on which white (yellow) lines could not be
recognized.