LEXUS GS 300 (2019 year). Instruction - part 16

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4-5. Using the driving support systems

■

Enabling/disabling the pre-collision system

The pre-collision system can be enabled/disabled on 

 (

P. 106, 114)

of the multi-information display.

The system is automatically enabled each time the engine switch is turned to IGNI-

TION ON mode.

If the system is disabled, the PCS
warning light will turn on and a mes-
sage will be displayed on the multi-
information display.

■

Changing the pre-collision warning timing
The pre-collision warning timing can be changed on 

 (

P. 106, 114)

of the multi-information display.

The operation timing setting is retained when the engine switch is turned off.

Far

The warning will begin to operate

earlier than with the default timing.

Middle

This is the default setting.

Near

The warning will begin to operate

later than with the default timing.

Changing settings of the pre-collision system

1

2

3

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Operational conditions
The pre-collision system is enabled and the system determines that the possibility of a

frontal collision with a vehicle or pedestrian is high.
Each function is operational at the following speeds:

●

Pre-collision warning:
• Vehicle speed is between approximately 7 and 110 mph (10 and 180 km/h). (For

detecting a pedestrian, vehicle speed is between approximately 7 and 50 mph [10

and 80 km/h].)

• The relative speed between your vehicle and the vehicle or pedestrian ahead is

approximately 7 mph (10 km/h) or more.

●

Pre-collision brake assist: 
• Vehicle speed is between approximately 20 and 110 mph (30 and 180 km/h). (For

detecting a pedestrian, vehicle speed is between approximately 20 and 50 mph

[30 and 80 km/h].)

• The relative speed between your vehicle and the vehicle or pedestrian ahead is

approximately 20 mph (30 km/h) or more.

●

Pre-collision braking:
• Vehicle speed is between approximately 7 and 110 mph (10 and 180 km/h). (For

detecting a pedestrian, vehicle speed is between approximately 7 and 50 mph [10

and 80 km/h].)

• The relative speed between your vehicle and the vehicle or pedestrian ahead is

approximately 7 mph (10 km/h) or more.

The system may not operate in the following situations:

●

If a battery terminal has been disconnected and reconnected and then the vehicle has

not been driven for a certain amount of time

●

If the shift lever is in R

●

If VSC is disabled (only the pre-collision warning function will be operational)

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4-5. Using the driving support systems

■

Pedestrian detection function

■

Cancelation of the pre-collision braking
If either of the following occur while the pre-collision braking function is operating, it will

be canceled:

●

The accelerator pedal is depressed strongly.

●

The steering wheel is turned sharply or abruptly.

■

Conditions under which the system may operate even if there is no possibility of a colli-

sion

●

In some situations such as the following, the system may determine that there is a possi-

bility of a frontal collision and operate.
• When passing a vehicle or pedestrian

• When changing lanes while overtaking a preceding vehicle

• When overtaking a preceding vehicle that is changing lanes

The pre-collision system detects pedestrians

based on the size, profile, and motion of a

detected object. However, a pedestrian may not

be detected depending on the surrounding

brightness and the motion, posture, and angle of

the detected object, preventing the system from

operating properly. (

P. 254)

• When overtaking a preceding vehicle that

is making a left/right turn

• When passing a vehicle in an oncoming

lane that is stopped to make a right/left turn

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4-5. Using the driving support systems

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• When rapidly closing on a vehicle ahead

• If the front of the vehicle is raised or lowered, such as when the road surface is

uneven or undulating

• When approaching objects on the roadside, such as guardrails, utility poles, trees, or

walls

• When driving on a narrow path surrounded by a structure, such as in a tunnel or on

an iron bridge

• When there is a metal object (manhole cover, steel plate, etc.), steps, or a protrusion

on the road surface or roadside

• When driving on a road where relative

location to vehicle ahead in an adjacent

lane may change, such as on a winding

road

• When there is a vehicle, pedestrian, or

object by the roadside at the entrance of a

curve

• When a crossing pedestrian approaches

very close to the vehicle

• When passing through a place with a low

structure above the road (low ceiling, traffic

sign, etc.)

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4-5. Using the driving support systems

• When rapidly closing on an electric toll gate barrier, parking area barrier, or other

barrier that opens and closes

• When using an automatic car wash

• When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead

• When driving through steam or smoke

• When there are patterns or paint on the road or a wall that may be mistaken for a

vehicle or pedestrian

• When driving near an object that reflects radio waves, such as a large truck or

guardrail

• When driving near a TV tower, broadcasting station, electric power plant, or other

location where strong radio waves or electrical noise may be present

• When passing under an object (billboard,

etc.) at the top of an uphill road

• When driving through or under objects

that may contact the vehicle, such as thick

grass, tree branches, or a banner

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Situations in which the system may not operate properly

●

In some situations such as the following, a vehicle may not be detected by the radar

sensor and camera sensor, preventing the system from operating properly:
• If an oncoming vehicle is approaching your vehicle

• If a vehicle ahead is a motorcycle or bicycle

• When approaching the side or front of a vehicle

• If a preceding vehicle has a small rear end, such as an unloaded truck

• If a vehicle ahead is carrying a load which protrudes past its rear bumper

• If a vehicle ahead is irregularly shaped, such as a tractor or side car

• If the sun or other light is shining directly on a vehicle ahead

• If a vehicle cuts in front of your vehicle or emerges from beside a vehicle

• If a vehicle ahead makes an abrupt maneuver (such as sudden swerving, accelera-

tion or deceleration)

• When suddenly cutting behind a preceding vehicle

• When driving in inclement weather such as heavy rain, fog, snow or a sandstorm

• When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead

• When driving through steam or smoke

• When driving in a place where the surrounding brightness changes suddenly, such

as at the entrance or exit of a tunnel

• When a very bright light, such as the sun or the headlights of oncoming traffic, shines

directly into the camera sensor

• When the surrounding area is dim, such as at dawn or dusk, or while at night or in a

tunnel

• If a preceding vehicle has a low rear end,

such as a low bed trailer

• If a vehicle ahead has extremely high

ground clearance

• When a vehicle ahead is not directly in front

of your vehicle

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4-5. Using the driving support systems

• After the engine has started the vehicle has not been driven for a certain amount of

time

• While making a left/right turn and for a few seconds after making a left/right turn

• While driving on a curve and for a few seconds after driving on a curve

• If your vehicle is skidding

• If the wheels are misaligned

• If a wiper blade is blocking the camera sensor

• The vehicle is wobbling.

• The vehicle is being driven at extremely high speeds.

• When driving on a hill 

• If the radar sensor or camera sensor is misaligned

●

In some situations such as the following, sufficient braking force may not be obtained,

preventing the system from performing properly:
• If the braking functions cannot operate to their full extent, such as when the brake

parts are extremely cold, extremely hot, or wet

• If the vehicle is not properly maintained (brakes or tires are excessively worn,

improper tire inflation pressure, etc.)

• When the vehicle is being driven on a gravel road or other slippery surface

●

Some pedestrians such as the following may not be detected by the radar sensor and

camera sensor, preventing the system from operating properly:
• Pedestrians shorter than approximately 3.2 ft. (1 m) or taller than approximately

6.5 ft. (2 m)

• Pedestrians wearing oversized clothing (a rain coat, long skirt, etc.), making their sil-

houette obscure

• Pedestrians who are carrying large baggage, holding an umbrella, etc., hiding part

of their body

• Pedestrians who are bending forward or squatting

• Pedestrians who are pushing a stroller, wheelchair, bicycle or other vehicle

• Groups of pedestrians which are close together

• Pedestrians who are wearing white and look extremely bright

• Pedestrians in the dark, such as at night or while in a tunnel

• Pedestrians whose clothing appears to be nearly the same color or brightness as

their surroundings

• Pedestrians near walls, fences, guardrails, or large objects

• Pedestrians who are on a metal object (manhole cover, steel plate, etc.) on the road

• Pedestrians who are walking fast

• Pedestrians who are changing speed abruptly

• Pedestrians running out from behind a vehicle or a large object

• Pedestrians who are extremely close to the side of the vehicle (outside rear view

mirror, etc.)

• If the front of the vehicle is raised or low-

ered

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If the PCS warning light flashes or illuminates and a warning message is displayed on

the multi-information display
The pre-collision system may be temporarily unavailable or there may be a malfunction

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 a front sensor is dirty or covered with snow, etc.

• When the part of the windshield in front of the camera sensor is fogged up or cov-

ered with condensation or ice (Defogging the windshield: 

P. 322)

• 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 remains illuminated or the warning mes-

sage does not disappear even though the vehicle has returned to normal, the system

may be malfunctioning. Have the vehicle inspected by your Lexus dealer immediately.

■

If VSC is disabled

●

If VSC is disabled (

P. 299), the pre-collision brake assist and pre-collision braking

functions are also disabled.

●

The PCS warning light will turn on and “VSC Turned Off Pre-Collision Brake System

Unavailable” will be displayed on the multi-information display.

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4-5. Using the driving support systems

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 of the lane.



: If equipped

Summary of functions

Functions included in LKA system

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◆

Steering assist 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.

GS350/GS300: 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 warning buzzer sounds.
GS F: If the system detects that the

steering wheel has not been oper-

ated 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.

◆

Vehicle sway warning function

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.

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4-5. Using the driving support systems

◆

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.
GS350/GS300: 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 warning buzzer sounds.
GS F: If the system detects that the

steering wheel has not been oper-

ated 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.

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WARNING

■

Before using LKA system
Do not rely solely upon the LKA system. The LKA system does not automatically drive

the vehicle or reduce the amount of attention that must be paid to the area in front of

the vehicle. The driver must always assume full responsibility for driving safely by pay-

ing careful attention to the surrounding conditions and operating the steering wheel to

correct the path of the vehicle. Also, the driver must take adequate breaks when

fatigued, such as from driving for a long period of time.

Failure to perform appropriate driving operations and pay careful attention may lead to

an accident, resulting in death or serious injury.

■

To avoid operating LKA system by mistake
When not using the LKA system, use the LKA switch to turn the system off.

■

Situations unsuitable for LKA system
Do not use the LKA system in the following situations.

The system may not operate properly and lead to an accident, resulting in death or

serious injury.

●

A spare tire, tire chains, etc. are equipped.

●

When the tires have been excessively worn, or when the tire inflation pressure is low.

●

Tires which differ by structure, manufacturer, brand or tread pattern are used.

●

Objects or patterns that could be mistaken for white (yellow) lines are present on the

side of the road (guardrails, curbs, reflective poles, etc.).

●

Vehicle is driven on a snow-covered road.

●

White (yellow) lines are difficult to see due to rain, snow, fog, dust, etc.

●

Asphalt repair marks, white (yellow) line marks, etc. are present due to road repair.

●

Vehicle is driven in a temporary lane or restricted lane due to construction work.

●

Vehicle is driven on a road surface which is slippery due to rainy weather, fallen snow,

freezing, etc.

●

Vehicle is driven in traffic lanes other than on highways and freeways.

●

Vehicle is driven in a construction zone.

■

Preventing LKA system malfunctions and operations performed by mistake

●

Do not modify the headlights or place stickers, etc. on the surface of the lights.

●

Do not modify the suspension etc. If the suspension etc. needs to be replaced, con-

tact your Lexus dealer.

●

Do not install or place anything on the hood or grille. Also, do not install a grille guard

(bull bars, kangaroo bar, etc.).

●

If your windshield needs repairs, contact your Lexus dealer.

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4-5. Using the driving support systems

Press the LKA switch to turn the LKA system on.

The LKA indicator illuminates and a message is displayed on the multi-information

display.
Press the LKA switch again to turn the LKA system off.
When the LKA system is turned on or off, operation of the LKA system continues in

the same condition the next time the engine is started.

LKA indicator
The illumination condition of the
indicator informs the driver of the
system operation status.

Illuminated in white: 

LKA system is operating.
Illuminated in green: 

Steering wheel assistance of the steer-

ing assist function or lane centering

function is operating.
Flashing in orange: 

Lane departure alert function is operat-

ing.

Operation display of steering wheel
operation support
Indicates that steering wheel assistance of the steering assist function or lane
centering function is operating.

Turning LKA system on



GS350/GS300



GS F

Indications on multi-information display

1

2

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Lane departure alert function display
Displayed when the multi-information display is switched to the driving assist
system information screen.

■

Operation conditions of each function

●

Lane departure alert function
This function operates when all of the following conditions are met.
• LKA is turned on.

• Vehicle speed is approximately 32 mph (50 km/h) or more.

• System recognizes white (yellow) lines.

• Width of traffic lane is approximately 9.8 ft. (3 m) or more.

• 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 492 ft. (150 m).

• No system malfunctions are detected. (

P. 264)

●

Steering assist function
This function operates when all of the following conditions are met in addition to the

operation conditions for the lane departure alert function.

• Setting for “Steering Assist” in 

 of the multi-information display is set to “On”.

(

P. 106, 114)

• Vehicle is not accelerated or decelerated by a certain amount or more.

• Steering wheel is not operated with a steering force level suitable for changing

lanes.

• ABS, VSC, TRAC and PCS (Pre-Collision System) are not operating.

• TRAC or VSC is not turned off.

• GS F: Hands off steering wheel alert is not displayed. (

P. 263)

3



Inside of displayed white lines is
white



Inside of displayed white lines is
black

Indicates that the system is recognizing
white (yellow) lines. When the vehicle
departs from its lane, the white line dis-
played on the side the vehicle departs
from flashes orange.

Indicates that the system is not able to
recognize white (yellow) lines or is
temporarily canceled.

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●

Vehicle sway warning function
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. 106, 114)

• Vehicle speed is approximately 32 mph (50 km/h) or more.

• Width of traffic lane is approximately 9.8 ft. (3 m) or more.

• No system malfunctions are detected. (

P. 264)

●

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. 106, 114)

• System recognizes white (yellow) lines.

• Dynamic radar cruise control with full-speed range is operating.

• Width of traffic lane is approximately 8.2 to 13.5 ft. (2.5 to 4.1 m).

• 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 656 ft. (200 m).

• No system malfunctions are detected. (

P. 264)

• Vehicle does not accelerate or decelerate by a certain amount or more.

• Steering wheel is not operated with a steering force level suitable for changing

lanes.

• ABS, VSC, TRAC and PCS (Pre-Collision System) are not operating.

• TRAC or VSC is not turned off.

• GS F: Hands off steering wheel alert is not displayed. (

P. 263)

• Steering assist function is not operating.

■

Temporary cancellation of functions
When the operation conditions are no longer met, a function may be temporarily can-

celed. However, when the operation conditions are met again, operation of the function

is automatically restored. (

P. 261)

■

Steering assist function/lane centering function
Depending on the vehicle speed, lane departure situation, road conditions, etc., the

driver may not feel the function is operating or the function may not operate at all.

■

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.

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Hands off steering wheel warning
GS350/GS300:

Depending on the vehicle and road conditions, the warning may not operate.
GS F:

Depending on the vehicle and road conditions, the warning may not operate.

■

Vehicle sway warning function

Depending on the vehicle and road conditions, the warning may not operate.

When the system determines that the driver has

removed their hands from the steering wheel

while the steering assist function or lane center-

ing function is operating, a warning message

urging the driver to hold the steering wheel and

the symbol shown in the illustration are dis-

played on the multi-information display. 
If the driver continues to keep their hands off of

the steering wheel, a buzzer sounds and a warn-

ing message and the symbol shown in the illus-

tration are displayed on the multi-information

display. This warning also operates in the same

way when the driver continuously operates the

steering wheel only a small amount. Always

keep your hands on the steering wheel when

using this system, regardless of warnings. 

When the system determines that the driver has

removed their hands from the steering wheel

while the steering assist function or lane center-

ing function is operating, a warning message

urging the driver to hold the steering wheel and

the symbol shown in the illustration are dis-

played on the multi-information display. 
If the driver continues to keep their hands off of

the steering wheel, a warning message and the

symbol shown in the illustration are displayed on

the multi-information display, and the function is

temporarily canceled. This warning also oper-

ates in the same way when the driver continu-

ously operates the steering wheel only a small

amount. Always keep your hands on the steer-

ing wheel when using this system, regardless of

warnings.

When the system determines that the vehicle is

swaying while the vehicle sway warning function

is operating, a buzzer sounds and a warning

message urging the driver to rest and the sym-

bol shown in the illustration are simultaneously

displayed on the multi-information display.