brake Lexus GS350 2020 Service Manual

254
GS350_GS F_OM_OM30J07U_(U)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 ca mera sensor is misaligned
●In some situations such as the following, sufficient braking forc e 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 ra in 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 be hind 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

GS350_GS F_OM_OM30J07U_(U)
2554-5. Using the driving support systems
4
Driving
■If the PCS warning light flashes or illuminates and a warning message is displayed on
the multi-inform ation 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 ca mera 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 dirt y 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. 324)
• 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 in spected by your Lexus dealer immediately.
■If VSC is disabled
●If VSC is disabled (P. 300), the pre-collision brake assist and pre-collision braking
functions are also disabled.
●The PCS warning light will turn on and “V SC Turned Off Pre-Collision Brake System
Unavailable” will be displayed on the multi-information display.

GS350_GS F_OM_OM30J07U_(U)
2694-5. Using the driving support systems
4
Driving
This mode employs a radar sensor to detect the presence of vehicles up to
approximately 328 ft. (100 m) ahead, determines the current vehicle-to-vehicle
following distance, and operates to main tain 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 switch.
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 warning warns you when the system cannot
decelerate sufficie ntly to prevent your vehicle 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 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 vehicle-to-vehicle distance control mode
1
2
3

GS350_GS F_OM_OM30J07U_(U)
2734-5. Using the driving support systems
4
Driving
After the vehicle ahead of you starts off,
push the lever up.
Your vehicle will also resume follow-up
cruising if the accelerator pedal is
depressed after the vehicle ahead of
you starts off.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 25 mph (40 km/h) 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.
Resuming follow-up cruising when the vehicle has been stopped by sys-
tem control (vehicle-to-vehicle distance control mode)
Canceling and resuming the speed control
1
2
Approach warning (vehicle-to-vehicle distance control mode)

GS350_GS F_OM_OM30J07U_(U)
2754-5. Using the driving support systems
4
Driving
■Dynamic radar cruise control with full-speed range can be set when
●The shift lever is in D.
●Range 4 or higher of D has been selected by using the paddle shift switch.
●Vehicle speed is at or above approximately 30 mph (50 km/h).
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 below approximately 30 mph
(50 km/h).
■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.
■When the vehicle stops while follow-up cruising
●Pushing the lever up while the vehicle ahead stops will resume follow-up cruising if the
vehicle ahead starts off within approximatel y 3 seconds after the lever is pushed up.
●If the vehicle ahead starts off within 3 seconds after your vehicle stops, follow-up cruis-
ing will be resumed.
■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 at or below approximately 25 mph (40 km/h) when there are
no vehicles ahead.
●The preceding vehicle leaves the lane when yo ur vehicle is following at a vehicle speed
at or below approximately 25 mph (40 km/h). Otherwise, the sensor can not properly
detect the vehicle. (“CRUISE NOT AVAILA BLE No Preceding Vehicles” is displayed
on the multi-information display)
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is turned off.
●When snow mode is set.
●The sensor cannot detect correctly because it is covered in some way.
●Pre-collision braking is activated.
●The parking brake is operated.
●The vehicle is stopped by system 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 th e system. Contact your Lexus dealer.

276
GS350_GS F_OM_OM30J07U_(U)4-5. Using the driving support systems
■Automatic cancelation of co
nstant speed control mode
Constant speed control mode is automatica lly canceled in the following situations:
●Actual vehicle speed is more than approxim ately 10 mph (16 km/h) below the set vehi-
cle speed.
●Actual vehicle speed falls below approximately 25 mph (40 km/h).
●VSC is activated.
●TRAC is activated for a period of time.
●When the VSC or TRAC system is turned off.
●Pre-collision braking is activated.
If constant speed control mode is automati cally canceled for any other reason, there may
be a malfunction in the system . Contact your Lexus dealer.
■Brake system operation sound
If the brakes are applied automatically while the vehicle is in vehicle-to-vehicle distance
control mode, a brake system operation soun d may be heard. This does not indicate a
malfunction.
■Warning messages and buzzers for dynamic radar cruise control with full-speed range
Warning messages and buzzers are used to indicate a system malfunction or to inform
the driver of the need for ca ution while driving. If a warning message is shown on the
multi-information display, read the message and follow the instructions. ( P. 442)
■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 insuff icient 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. 273) 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

GS350_GS F_OM_OM30J07U_(U)
2774-5. Using the driving support systems
4
Driving
■Conditions under which the vehicle-to-vehicle distance control mode may not function
correctly
In the case of the following conditions, o perate the brake pedal (or accelerator pedal,
depending on the situ ation) as necessary.
As the sensor may not be able to correctly detect vehicles ahead, the system may not
operate properly.
●When the vehicle ahead of you decelerates suddenly
●When driving on a road surrounded by a struct ure, such as in a tunnel or on a bridge
●While the vehicle speed is decreasing to the set speed after the vehicle accelerates by
depressing the accelerator pedal
●When your vehicle is pointing upwards
(caused by a heavy load in the luggage com-
partment, etc.)
●Preceding vehicle has an extremely high
ground clearance
●When the road curves or when the lanes are
narrow
●When steering wheel operation or your posi-
tion in the lane is unstable

GS350_GS F_OM_OM30J07U_(U)
2794-5. Using the driving support systems
4
Driving
To change the set speed, operate the lever until the desired set speed is obtained.
Increases the speed
Decreases the speed
Fine adjustment: Momentarily move the
lever in the desired direction.
Large adjustment: Hold the lever in the
desired direction.
The set speed will be increased or decreased as follows:
Fine adjustment: By approximately 1 mph (1. 6 km/h) each time the lever is operated.
Large adjustment: The set speed can be increased or decreased continually until the
lever is released.
Pulling the lever toward you cancels
the constant speed control.
The speed setting is also canceled when
the brakes are applied.
Pushing the lever up resumes the
constant speed control.
Resuming is available when the vehicle
speed is more than approximately 25
mph (40 km/h).
■Cruise control can be set when
●The shift lever is in D.
●Range 4 or higher of D has been selected by using the paddle shift.
●Vehicle speed is above approximately 25 mph (40 km/h).
■Accelerating after setting the vehicle speed
●The vehicle can be accelerated normally. After acceleration, the set speed resumes.
●Even without canceling the cruise control, th e set speed can be increased by first accel-
erating the vehicle to the desired speed and then pushing the lever down to set the new
speed.
Adjusting the set speed
1
2
Canceling and resuming the constant speed control
1
2

297
GS350_GS F_OM_OM30J07U_(U)4-5. Using the driving support systems
4
Driving
Driving assist systems
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the br
akes are applied suddenly, or if the
brakes are applied while drivin g on a slippery road surface
◆Brake assist
Generates an increased level of br aking force after the brake pedal is
depressed when the system detects a panic stop situation
◆VSC (Vehicle Stability Control)
Helps the driver to contro l skidding when swerving suddenly or turning on
slippery road surfaces
◆Enhanced VSC (Enhanced Vehicle Stability Control)
Provides cooperative control of the ABS, TRAC, VSC and EPS.
Helps to maintain directional stability when swerving on slippery road sur-
faces by controlling steering performance.
◆TRAC (Traction Control)
Helps to maintain drive power and pr event the drive wheels from spinning
when starting the vehicle or accelerating on slippery roads
◆Hill-start assist control
Helps to prevent the vehicle from ro lling backward when starting on an
incline.
To help enhance driving safety and perf ormance, the following systems oper-
ate automatically in response to variou s driving situations. Be aware, however,
that these systems are supplementary and should not be relied upon too heav-
ily when operating the vehicle.

298
GS350_GS F_OM_OM30J07U_(U)4-5. Using the driving support systems
◆VGRS (Variable Gear Ratio Steering) (if equipped)
Adjusts the front wheel turning angle
in accordance with the vehicle speed
and steering wheel movement
◆DRS (Dynamic Rear Steering) (if equipped)
Contributes to the turning characteristi cs and responsiveness of the vehicle
by slightly adjusting the rear wheel angle of the vehicle in accordance with
steering wheel movement
◆EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn the
steering wheel
◆AVS (Adaptive Variable Suspension system) (if equipped)
By independently controlling the dampin g force of the shock absorbers for
each of the 4 wheels according to the ro ad and driving conditions, this system
helps riding comfort with superior a high level of stability, and helps good vehi-
cle posture
When SPORT S+ mode is selected by the driving mode select switch, the
damping force is suitable for sporty driving (P. 281)
◆LDH (Lexus Dynamic Hand ling system) (if equipped)
Provides independent control of the VGRS, DRS and EPS. Contributes to
turning characteristics at low speeds, responsiveness at medium speeds and
safety at high speeds by controlling th e steering angle of the front and rear
wheels in accordance with the steeri ng wheel operation and vehicle speed
◆VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, TRAC, VSC, hill-start
assist control, EPS, VGRS (if equipped) and DRS (if equipped) systems
Helps to maintain vehicle stability when swerving on slippery road surfaces by
controlling the brakes, engine output, steering assist, steering ratio and rear
wheel angle