cruise control Lexus GS300h 2017 User Guide

2824-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
LKA (Lane-Keeping Assist) 
When driving on highways and freeways with white or yellow l
ines, 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 of the lane.
: If equipped
Summary of functions
Functions included in LKA system

2844-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(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.
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.
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.

2964-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
Dynamic radar cruise control with full-speed
range 
In vehicle-to-vehicle distance control mode, the vehicle automatically acceler-
ates, decelerates and stops to match the speed changes of the preceding vehicle
even if the accelerator pedal is not depr
essed. In constant speed control mode,
the vehicle runs at a fixed speed.
Use the dynamic radar cruise control with full-speed range on freeways and
highways. ● Vehicle-to-vehicle distance control mode ( P. 299)
● Constant speed control mode ( P. 304)
Vehicle-to-vehicle distance button
Display
Set speed
Indicators
Cruise control switch
: If equipped
Summary of functions
1
2
3
4
5

297
4-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Before using dynamic radar cruise control with full-speed range
Driving safely is the sole resp onsibility of the driver. Do not rely solely on the system,
and drive safely by always paying careful attention to your surroundings.
The dynamic radar cruise control with full-speed range provides driving assistance to
reduce the driver’s burden. However, there are limitations to the assistance provided.
Even when the system is functioning norma lly, the condition of the preceding vehicle as
detected by the system may differ from the condition observed by the driver. There-
fore, the driver must always remain alert, assess the danger of each situation and drive
safely. Relying on this system or assuming the system ensures safety while driving can
lead to an accident, resulting in death or serious injury.
■Cautions regarding the driving assist systems
Observe the following precautions, as there are limitations to the assistance provided
by the system.
Failure to do so may cause an accident resulting in death or serious injury.
●Assisting the driver to measure following distance
The dynamic radar cruise control with full-sp eed range is only intended to help the
driver in determining the fo llowing distance between the driver’s own vehicle and a
designated vehicle traveling ahead. It is no t a mechanism that allows careless or inat-
tentive driving, and it is not a system that can assist the driver in low-visibility condi-
tions. It is still necessary for driver to pay close attention to the vehicle’s surroundings.
●Assisting the driver to judge proper following distance
The dynamic radar cruise control with full-speed range determines whether the fol-
lowing distance between the driver’s own vehicle and a designated vehicle traveling
ahead is within a set range. It is not capable of making any other type of judgement.
Therefore, it is absolutely necessary for the driver to remain vigilant and to determine
whether or not there is a possibility of danger in any given situation.
●Assisting the driver to operate the vehicle
The dynamic radar cruise control with full-speed range has limited capability to pre-
vent or avoid a collision with a vehicle trave ling ahead. Therefore, if there is ever any
danger, the driver must take immediate and direct control of the vehicle and act
appropriately in order to ensure the safety of all involved.
■To avoid inadvertent dynamic radar cruise control with full-speed range activation
Switch the dynamic radar cruise control wi th full-speed range off using the “ON/OFF”
button when not in use.

2984-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Situations unsuitable for dynamic radar cruise control with full-speed range
Do not use dynamic radar cruise control with full-speed range in any of the following
situations.
Doing so may result in inappropriate speed control and could cause an accident result-
ing in death or serious injury.
●Roads where there are pedestrians, cyclists, etc.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as those covered with rain, ice or snow
●On steep downhills, or where there are sudden changes between sharp up and down
gradients
Vehicle speed may exceed the set sp eed when driving down a steep hill.
●At entrances to freeways and highways
●When weather conditions are bad enough that they may prevent the se nsors from
detecting correctly (fog, snow, sandstorm, heavy rain, etc.)
●When there is rain, snow, etc. on the fron t surface of the radar sensor or camera sen-
sor
●In traffic conditions that require frequent repeated acceleration and deceleration
●When your vehicle is towing a trailer (vehicles with towing package) or during emer-
gency towing
●When an approach warning buzzer is heard often

299
4-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE) This mode employs a radar sensor to detect the presence of vehicles up to
approximately 100 m (328 ft.) ahead, determines the current vehicle-to-vehicle
following distance, and operates to maintain a suitable following distance from
the vehicle ahead.
Note that vehicle-to-vehicle distance will close in when traveling on long downhill
slopes.
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehicle dis-
tance can also be set by operating the vehicle-to-vehicle distance button.
Example of deceleration cruising and follow-up cruising
When a preceding vehicle driving slower than the set speed appears
When a vehicle is detected running ahead of you, the system automatically deceler-
ates your vehicle. When a greater reduction in vehicle speed is necessary, the system
applies the brakes (the stop lights will come on at this time). The system will respond to
changes in the speed of the vehicle ahead in order to maintain the vehicle-to-vehicle
distance set by the driver. Approach wa rning warns you when the system cannot
decelerate sufficiently to prevent your vehicle from closing in on the vehicle ahead.
When the vehicle ahead of you stops, your ve hicle will also stop (vehicle is stopped by
system control). After the vehicle ahead starts off, pushing the cruise control lever up
or depressing the accelerator pedal will resume follow-up cruising.
Example of acceleration
When there are no longer any preceding vehicles driving slower than the set
speed
The system accelerates until the set speed is reached. The system then returns to con-
stant speed cruising.
Driving in vehicl e-to-vehicle distance control mode
1
2
3

3004-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE) Press the “ON/OFF” button to acti-
vate the cruise control.
Radar cruise control indicator will come
on and a message will be displayed on
the multi-information display.
Press the button again to deactivate the
cruise control.
If the “ON/OFF” button is pressed and
held for 1.5 seconds or more, the system
turns on in constant speed control
mode. (
P. 304)
Accelerate or decelerate, with
accelerator pedal operation, to the
desired vehicle speed (above
approximately 50 km/h [30 mph])
and push the lever down to set the
speed.
Cruise control “SET” indicator will come
on.
The vehicle speed at the moment the
lever is released becomes the set speed.
If the lever is operated while the vehi cle speed is below approximately 50 km/h
(30 mph) and a preceding vehicle is present, the set speed will be adjusted to approx-
imately50 km/h (30 mph).
Setting the vehicle speed (vehicle-t o-vehicle distance control mode)
1
2

303
4-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE) Pulling the lever toward you cancels
the speed control.
The speed control is also canceled when
the brake pedal is depressed.
(When the vehicle has been stopped by
system control, depressing the brake
pedal does not cancel the setting.)
Pushing the lever up resumes the
cruise control and returns vehicle
speed to the set speed.
However, when a vehicle ahead is not detected, cruise control does not resume when
the vehicle speed is approximately 40 km/h (25 mph) or less.
When your vehicle is too close to a
vehicle ahead, and sufficient automatic
deceleration via the cruise control is
not possible, the display will flash and
the buzzer will sound to alert the driver.
An example of this would be if another
driver cuts in front of you while you are
following a vehicle. Depress the brake
pedal to ensure an appropriate vehicle-
to-vehicle distance.
■Warnings may not occur when
In the following instances, warnings may not occur even when the vehicle-to-
vehicle distance is small. ● When the speed of the preceding vehicle matches or exceeds your vehicle
speed
● When the preceding vehicle is traveling at an extremely slow speed
● Immediately after the cruise control speed was set
● When depressing the accelerator pedal
Canceling and resuming the speed control
1
2
Approach warning (vehicle-to- vehicle distance control mode)

3044-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE) When constant speed control mode is selected, your vehicle will maintain a set
speed without controlling the vehicle-to-vehicle distance. Select this mode
only
when vehicle-to-vehicle distance control mode does not fu nction correctly due
to a dirty radar sensor, etc.
With the cruise control off, press and
hold the “ON/OFF” button for 1.5
seconds or more.
Immediately after the “ON/OFF” but-
ton is pressed, the radar cruise control
indicator will come on. Afterwards, it
switches to the cruise control indicator.
Switching to constant speed control
mode is only possible when operating
the lever with the cruise control off.
Accelerate or decelerate, with
accelerator pedal operation, to the
desired vehicle speed (above
approximately 50 km/h [30 mph])
and push the lever down to set the
speed.
Cruise control “SET” indicator will come
on.
The vehicle speed at the moment the
lever is released becomes the set speed.
Adjusting the speed setting: P. 301
Canceling and resuming the speed setting: P. 303
Selecting constant speed control mode
1
2

305
4-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
■Dynamic radar cruise control with full-speed range can be set when
●The shift lever is in D or range 4 or higher of S has been selected.
●Range 4 or higher of D has been select ed by using the paddle shift switch.
●Vehicle speed is above approximately 50 km/h (30 mph).
However, when a preceding vehicle is dete cted, the dynamic radar cruise control with
full-speed range can be set even if the vehicle speed is at or below approximately
50 km/h (30 mph).
■Accelerating after setting the vehicle speed
The vehicle can accelerate by operating the accelerator pedal. After accelerating, the
set speed resumes. However, during vehicle- to-vehicle distance control mode, the vehi-
cle speed may decrease below the set speed in order to maintain the distance to the pre-
ceding vehicle.
■Automatic cancelation of vehicle -to-vehicle distance control mode
Vehicle-to-vehicle distance control mode is automatically canceled in the following situ-
ations.
●Actual vehicle speed falls below approximat ely 40 km/h (25 mph) when there are no
vehicles ahead.
●The preceding vehicle leaves the lane when your vehicle is following at a vehicle speed
below approximately 40 km/h (25 mph). Otherwise, the sensor can not properly
detect the vehicle.
●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 snow mode is set.
●The sensor cannot detect correctly because it is covered in some way.
●Pre-crash braking is activated.
●The parking brake is operated.
●The vehicle is stopped by syst em control on a steep incline.
●The following are detected when the vehicle has been stopped by system control: