2015 Lexus GS450h brake sensor

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4-3. Operating the lights and wipers
■Daytime running light system
●To make your vehicle more visible to other drivers, the parking lights turn on auto-
matically (at an increased intensity) whenever the hybrid system is started and the
parking brake is released. Daytime running lights are not designed for use at night.
For the U.S.A.: Daytime running lights can be turned off by operating the switch.
●Compared to turning on th e headlights, the daytime running light system offers
greater durability and consumes less electricity, so it can help improve fuel econ-
omy.
■Headlight control sensor
■Automatic light off system
When the light switch is in or : The headlights and tail lights turn off 30 sec-
onds after the power switch is turned to ACCESSORY mode or turned off and a
door is opened and all of the doors and trun k are closed. (The lights turn off immedi-
ately if on the key is pressed twice after all the doors are closed.)
To turn the lights on again, turn the power switch to ON mode, or turn the light
switch off once and then back to or .
If any of the doors or trunk lid is kept op en, the lights automatically turn off after 20
minutes.
■Light reminder buzzer
A buzzer sounds when the power switch is turned off or turned to ACCESSORY
mode and the driver’s door is opened while the lights are turned on.
■Automatic headlight leveling system
The level of the headlights is automatically adjusted according to the number of pas-
sengers and the loading conditio n of the vehicle to ensure that the headlights do not
interfere with other road users. The sensor may not func tion properly if an
object is placed on the sensor, or anything
that blocks the sensor is affixed to the wind-
shield.
Doing so interferes with the sensor detecting
the level of ambient light and may cause the
automatic headlight system to malfunction.

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2454-5. Using the driving support systems
4
Driving
This mode employs a radar sensor to detect the presence of vehicles up to
approximately 400 ft. (120 m) ahead, determines the current vehicle-to-
vehicle following distance, and opera tes 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
distance can also be set by operating the vehicle-to-vehicle distance control.
Example of deceleration cruising
When the vehicle ahead is driving slower than the set speed
When a vehicle is detected running ahead of you, the system automatically decel-
erates your vehicle. When a greater reduction in vehicle speed is necessary, the
system applies the brakes. A warning tone warns you when the system cannot
decelerate sufficiently to prevent your vehicle from closing in on the vehicle
ahead.
Driving in vehicle-to-vehicle distance control mode
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2

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2534-5. Using the driving support systems
4
Driving
CAUTION
■When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are in
front of you.
As the sensor may not be able to correc tly detect these types of vehicles, the
approach warning ( P. 246) will not be activated, and a fatal or serious accident
may result.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving
●Vehicles with small rear ends (trailers with no load on board etc.)
●Motorcycles traveling in the same lane
■Conditions under which the vehicle-to-veh icle distance control may not function
correctly
Apply the brakes as necessary in the following conditions as the radar sensor may
not be able to correctly detect vehicles ahead, and a fatal or serious accident may
result:
●When water or snow thrown up by the surrounding vehicles hinders the function-
ing of the sensor
●When your vehicle is pointing upwards (caused by a heavy load in the trunk etc.)
●When the road curves or when the lanes are narrow
●When steering wheel operation or your position in the lane is unstable
●When the vehicle ahead of you decelerates suddenly

GS450h_OM_OM30E26U_(U)
2614-5. Using the driving support systems
4
Driving
This mode employs a radar sensor to detect the presence of vehicles up to
approximately 400 ft. (120 m) ahead, determines the current vehicle-to-
vehicle following distance, and opera tes 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
distance can also be set by operating the vehicle-to-vehicle distance control.
Example of deceleration cruising and follow-up cruising
When the vehicle ahead is driving slower than the set speed
When a vehicle is detected running ahead of you, the system automatically decel-
erates your vehicle. When a greater reduction in vehicle speed is necessary, the
system applies the brakes. 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. A warning tone 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 vehicle will also stop. After the vehicle ahead starts off,
pushing the cruise control lever up or depressing the accelerator pedal will
resume follow-up cruising.
Driving in vehicle-to-vehicle distance control mode
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2

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4-5. Using the driving support systems
■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 selected by using the paddle shift.
●Vehicle speed is above approximately 30 mph (50 km/h).
■Accelerating after setting the vehicle speed
The vehicle can accelerate normally. After acceleration, the set speed resumes.
However, during vehicle-to-vehicle distance control mode, the vehicle speed may
decrease below the set speed in order to maintain the distance to the vehicle ahead.
■Automatic cancelation of vehicle-to-vehicle distance control
Vehicle-to-vehicle distance control driving is automatically canceled in the following
situations:
●Actual vehicle speed falls below approximately 25 mph (40 km/h) when there are
no vehicle ahead.
●The preceding vehicle leaves the lane when your vehicle is following at a speed
below 25 mph (40 km/h).
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is turn ed off by pressing the VSC OFF switch.
●The sensor cannot operate correctly because it is covered in some way.
●The windshield wipers are operating at hi gh speed (when the wiper switch is set to
AUTO mode or the high speed wiper operation).
●When snow mode is set.
●The parking brake is operated.
●The vehicle is stopped by system control on a steep incline.
●Pre-collision brake assist is activated.
●The following are detected when the vehi cle has been stopped by system control:
• The driver is not wearing a seat belt.
• The driver’s door is opened.
• The trunk or hood is opened.
• The vehicle has been stopped for about 3 minutes.
If vehicle-to-vehicle distance control driv ing is automatically canceled for any other
reason, there may be a malfunction in the system. Contact your Lexus dealer.

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2694-5. Using the driving support systems
4
Driving
CAUTION
■When the radar sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are in
front of you.
As the sensor may not be able to correctly detect these types of vehicles, the
approach warning ( P. 262) will not be activated, and a fatal or serious accident
may result.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Motorcycles traveling in the same lane
●Vehicles that are not moving
●Vehicles with small rear ends (trailers with no load on board etc.)
●Details about other people/objects the system will not detect:
 P. 2 6 7
■Conditions under which the vehicle-to-veh icle distance control may not function
correctly
Apply the brakes as necessary in the following conditions as the radar sensor may
not be able to correctly detect vehicles ahead, and a fatal or serious accident may
result:
●When water or snow splashed by the su rrounding vehicles hinders the function-
ing of the radar sensor
●When your vehicle is tilted upwards (due to a heavy load in the trunk etc.)
●When the road curves or when the lanes are narrow
●When steering wheel operation or your position in the lane is unstable
●When the vehicle ahead decelerates suddenly as the system is not able to
respond to sudden braking.
Details about limitations:
 P. 2 6 7
Details about unsuitable conditions:
 P. 2 6 8

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Driving
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. 3 4 )
◆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 the possibility of a frontal collision, the
pre-collision system 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. 2 9 3 )

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4-5. Using the driving support systems
■Conditions that may trigger the system even if there is no danger of a collision
●When there is an object by the roadside at the entrance to a curve
●When passing an oncoming vehicle on a curve
●When driving over a narrow iron bridge
●When there is a metal object on the road surface
●When driving on an uneven road surface
●When passing an oncoming vehicle on a left-turn
●When your vehicle rapidly closes on the vehicle in front
●When a grade separation/interchange, sign , billboard, or other structure appears
to be directly in the vehicle’s line of travel
●When climbing a steep hill causes an overhead billboard or other metallic structure
to appear directly in the vehicle’s line of travel
When the system is activated in the situations described above, there is also a possi-
bility that the seat belts will retract quickly and the brakes will be applied with a force
greater than normal. When the seat belt is locked in the retracted position, stop the
vehicle in a safe place, release the seat belt and refasten it.
■Obstacles not detected
The sensor cannot detect plastic obstacles such as traffic cones. There may also be
occasions when the sensor cannot detect pedestrians, animals, bicycles, motorcy-
cles, trees, or snowdrifts.
■Situations in which the pre-collision system does not function properly
The system may not function effectively in situations such as the following:
●On roads with sharp bends or uneven surfaces
●If a vehicle suddenly moves in front of your vehicle, such as at an intersection
●If a vehicle suddenly cuts in front of your vehicle, such as when overtaking
●In inclement weather such as heavy rain, fog, snow or sand storms
●When your vehicle is skidding
●When your vehicle is steeply inclined
●When the radar sensor moves off position due to its surrounding area being sub-
jected to a strong impact