brake Lexus GS300h 2016 Service Manual

2704-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
◆Pre-crash braking*3
When the system determines that the possibility of a frontal collision is high,
the system warns the driver. If the system determines that the possibility of a
collision is extremely high, the brakes are automatically applied to help avoid
the collision or reduce the collision speed.
*3: Depending on the region in which the vehicle was sold, the pre-crash braking function may not be available.
◆Suspension control (if equipped)
When the system determines that the possibility of a frontal collision is high,
the Adaptive Variable Suspension system ( →P. 345) will control the damping
force of the shock absorbers.
◆Steering control (if equipped)
When the system determines that the possibility of a frontal collision is high
and the driver is operating the steering wheel, the LDH system ( →P. 345) will
control the turning angle of the front an d rear wheels and effort necessary to
turn the steering wheel.
WA R N I N G
■Limitations of the pre-crash safety system
●The driver is solely responsible for safe driving. Always drive safely, taking care to
observe your surroundings.
Do not use the pre-crash safety system instead of normal braking operations under
any circumstances. This system will not pr event collisions or lessen collision damage
or injury in every situation. Do not overly rely on this system. Failure to do so may lead
to an accident, resulting in death or serious injury.
●Although this system is designed to help av oid a collision or help reduce the impact of
the collision, its effectiveness may change according to various conditions, therefore
the system may not always be able to achieve the same level of performance.
Read the following conditions carefully. Do not overly rely on this system and always
drive carefully.
• Conditions under which the system may oper ate even if there is no possibility of a
collision: →P. 2 7 5
• Conditions under which the system may not operate properly: →P. 2 7 8
●Do not attempt to test the operation of the pre-crash safety system yourself, as the
system may not operate properly, possibly leading to an accident.

2714-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
WA R N I N G
■Pre-crash braking*3
●The pre-crash braking function may not operate if certain operations are performed
by the driver. If the accelerator pedal is being depressed strongly or the steering
wheel is being turned, the system may determine that the driver is taking evasive
action and possibly prevent the pre-crash braking function from operating.
●In some situations, while the pre-crash braking function is operating, operation of the
function may be canceled if the accelerator pedal is depressed strongly or the steer-
ing wheel is turned and the system determines that the driver is taking evasive action.
●A large amount of braking force is applied while the pre-crash braking function is
operating. As the pre-crash braking function will be canceled after the vehicle has
been stopped for approximately 2 seconds, the driver should depress the brake
pedal as necessary.
●If the brake pedal is being depressed, the system may determine that the driver is tak-
ing evasive action and possibly delay the operation timing of the pre-crash braking
function.
*3: Depending on the region in which the vehicle was sold, the pre-crash braking func-
tion may not be available.
■When to disable the pre-crash safety system
In the following situations, disable the system, as it may not operate properly, possibly
leading to an accident resulting in death or serious injury:
●When the vehicle is being towed
●When your vehicle is towing another vehicle
●When transporting the vehicle via truck, boat, train or similar means of transportation
●When the vehicle is raised on a lift with the hybrid system operating and the tires are
allowed to rotate freely
●When inspecting the vehicle using a drum tester such as a chassis dynamometer or
speedometer tester, or when using an on vehicle wheel balancer
●When a strong impact is applied to the front bumper or front grille, due to an accident
or other reasons
●If the vehicle cannot be driven in a stable manner, such as when the vehicle has been
in an accident or is malfunctioning
●When the vehicle is driven in a sporty manner or off-road
●When the tires are not properly inflated
●When the tires are very worn
●When tires of a size other than specified are installed
●When tire chains are installed
●When a compact spare tire or an emergency tire puncture repair kit is used

2734-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
■Operational conditions
Availability of the pedestrian detection function and pre-crash braking function depend
on the region in which the vehicle was sold.
Read the following for details:
XRegion A
(The pedestrian detection function and pre-crash braking function are available)
The pre-crash safety system is enabled and th e 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-crash warning:
• Vehicle speed is between approximately 10 and 180 km/h (7 and 110 mph). (For detecting a pedestrian, vehicle speed is between approximately 10 and 80 km/h [7
and 50 mph].)
• The relative speed between your vehicle and the vehicle or pedestrian ahead is approximately 10 km/h (7 mph) or more.
●Pre-crash brake assist:
• Vehicle speed is between approximately 30 and 180 km/h (19 and 110 mph). (Fordetecting a pedestrian, vehicle speed is between approximately 30 and 80 km/h
[19 and 50 mph].)
• The relative speed between your vehicle and the vehicle or pedestrian ahead is approximately 30 km/h (19 mph) or more.
●Pre-crash braking:
• Vehicle speed is between approximately 10 and 180 km/h (7 and 110 mph). (For
detecting a pedestrian, vehicle speed is between approximately 10 and 80 km/h [7
and 50 mph].)
• The relative speed between your vehicle and the vehicle or pedestrian ahead is
approximately 10 km/h (7 mph) 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-crash warning function will be operational)
●If the PCS warning light is flashing or illuminated
RegionsFunction availability
Region AThe pedestrian detection function and pre-crash braking func-
tion are available
Region BThe pedestrian detection function is not available and the pre-
crash braking function is available
Region CThe pedestrian detection function and pre-crash braking func-
tion are not available

2744-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
XRegion B
(The pedestrian detection function is not available and the pre-crash braking function
is available)
The pre-crash safety system is enabled and th e system determines that the possibility of a
frontal collision with a vehicle is high.
Each function is operational at the following speeds:
●Pre-crash warning:
• Vehicle speed is between approximately 15 and 180 km/h (10 and 110 mph).
• The relative speed between your vehicle and the vehicle ahead is approximately
10 km/h (7 mph) or more.
●Pre-crash brake assist:
• Vehicle speed is between approximately 30 and 180 km/h (19 and 110 mph).
• The relative speed between your vehicle and the vehicle ahead is approximately30 km/h (19 mph) or more.
●Pre-crash braking:
• Vehicle speed is between approximately 15 and 180 km/h (10 and 110 mph).
• The relative speed between your vehicle and the vehicle ahead is approximately10 km/h (7 mph) 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-crash warning function will be operational)
●If the PCS warning light is flashing or illuminated
XRegion C
(The pedestrian detection function and pre-crash braking function are not available)
The pre-crash safety system is enabled and th e system determines that the possibility of a
frontal collision with a vehicle is high.
Each function is operational at the following speeds:
●Pre-crash warning:
• Vehicle speed is between approximately 15 and 180 km/h (10 and 110 mph).
• The relative speed between your vehicle and the vehicle ahead is approximately 10 km/h (7 mph) or more.
●Pre-crash brake assist:
• Vehicle speed is between approximately 30 and 180 km/h (19 and 110 mph).
• The relative speed between your vehicle and the vehicle ahead is approximately30 km/h (19 mph) 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-crash warning function will be operational)
●If the PCS warning light is flashing or illuminated

2794-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)• After the hybrid system 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 front of the vehicle is raised or lowered
• 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, su fficient 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
*4:
• Pedestrians shorter than approximately 1 m (3.2 ft.) or taller than approximately 2 m (6.5 ft.)
• 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 th e side of the vehicle (outside rear view
mirror, etc.)
*4: Depending on the region in which the vehicle was sold, the pedestrian detection
function may not be available.

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.

3064-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(EE)
This mode employs a radar sensor to detect the presence of vehicles up to
approximately 120 m (400 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 ve hicle from closing in on the vehicle ahead.
When the vehicle ahead of you stops, your vehicle will also stop (vehicle is stopped by
system control). After the vehicle ahead star ts 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 vehicle-to-veh icle distance control mode
1
2
3

3104-5. Using the driving support systems
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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.
■Wa r n i n g s m a y n o t o c c u r w h e n
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)

3124-5. Using the driving support systems
GS450h_300h_OM_OM30F00E_(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 selected by using the paddle shift switch.
●Vehicle speed is above approximately 50 km/h (30 mph).
However, when a preceding vehicle is detected, 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 approximately 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:
• The driver is not wearing a seat belt.
• The driver’s door is opened.
• The vehicle has been stopped for about 3 minutes
If vehicle-to-vehicle distance control mode is automatically canceled for any other rea-
son, there may be a malfunction in the system. Contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.

3134-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F00E_(EE)
■Automatic cancelation of constant speed control mode
Constant speed control mode is automatically canceled in the following situations:
●Actual vehicle speed is more than approximately 16 km/h (10 mph) below the set vehi-
cle speed.
●Actual 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.
●Pre-crash braking is activated.
If constant speed control mode is automatically canceled for any other reason, there may
be a malfunction in the system. Contact any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
■Warning messages and buzzers for dynamic radar cruise control with full-speed range
Warning messages and buzzers are used to in dicate a system malfunction or to inform
the driver of the need for caution while driv ing. If a warning message is shown on the
multi-information display, read the message and follow the instructions. ( →P. 4 8 2 )
■When the sensor may not be correctly detecting the vehicle ahead
In the case of the following and depending on the conditions, operate the brake pedal
when deceleration of the system is insufficient or operate the accelerator pedal when
acceleration is required.
As the sensor may not be able to correctly detect these types of vehicles, the approach
warning ( →P. 310) may not be activated.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving in the same lane
●Vehicles with small rear ends (traile rs with no load on board, etc.)
●Motorcycles traveling in the same lane
●When water or snow thrown up by the surrounding vehicles hinders the detecting of
the sensor