2011 Lexus HS250h warning

221
2-4. Using other driving systems
2
When driving
LKA (Lane-Keeping Assist)
: If equipped
While driving on a freeway or motor highway that has lane markers, this
system recognizes the lanes using a camera as a sensor to assist the driver
with staying in the lane. The LKA system has two functions.
■Lane departure warning function
If the system judges that the vehi cle may deviate from its lane, it
alerts the driver using rapid beepin g, indications on the multi-infor-
mation display, and a sensory warning
* given via the steering wheel.
*:A slight steering torque is applied fo r a short period of time in the
direction of the center of the lane.
■ Lane keeping assist function
This function will be active when the vehicle-to-vehicle distance
control mode of the cruise control ( P. 208) is set with vehicle
speed above approx. 45 mph (appr ox. 72 km/h) and while the lane
departure warning function is acti ve. When the lane keeping assist
function is active, a slight steering torque will be applied, to help the
driver maintain the vehicle inside the lane.

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2-4. Using other driving systems
■Turning the LKA system on
The lane departure warning function and lane keeping assist func-
tion will be activated depending on the recog nition condition of lane
markers, vehicle speed and the setting of radar cruise control (vehi-
cle-to-vehicle dist ance control mode).
Press the “LKA” switch to acti-
vate the system.
“LKA” indicator will come on.
Press the switch again to turn
the LKA system off.

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2-4. Using other driving systems
2
When driving
■Operating conditions for each function
*1: Vehicle speed is between about 30 and 125 mph (48 and 200 km/h)
*2: Vehicle speed is between about 45 and 112 mph (72 and 180 km/h).
“LKA”
switchCruise control
(vehicle-to-vehicle
distance control mode)Lane departure warning
function
*1
Lane keeping
assist function*2
On
OffAv a i l a b l eNot available
On
(While cruising in vehi- cle-to-vehicle distance
control mode with the set vehicle speed
approx. 44 mph [approx. 71 km/h] or less)
Av a i l a b l eNot available
On
(While cruising in vehi- cle-to-vehicle distance
control mode with the set vehicle speed
approx. 45 mph [approx.
72 km/h] or more)
Av a i l a b l eAvailable

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2-4. Using other driving systems
Indication on the multi-information displayWhile the LKA system is on, the lane line display and steering wheel dis-
play (in case of lane k eeping assist function) are shown on the multi-infor-
mation display to inform that the LKA system is on.
Steering wheel display
The lane keeping assist function is
active.
Dynamic radar cruise control
display
Lane line display
When thin lines are shown:
A lane marker is not recognized by
the system, or the LKA system
functions are temporarily can-
celed.
When solid lane lines are shown:
The lane departure warning func-
tion is active.
■Temporary cancellation of the LKA system functions
If any of the following occurs, the LKA system functions will be temporarily can-
celed. The functions will resume after the necessary operating conditions have
returned.
●The turn signal lever is operated.
●The steering wheel is turned as far as necessary to cause the vehicle to change
lanes.
●The brake pedal is depressed.
However, the lane keeping assist function will not resume even after the brake
pedal is released because depressing the brake pedal also cancels the dynamic
radar cruise control. (only lane departure warning function will resume)
●The vehicle speed deviates from the op erating range of the LKA system func-
tions.

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2-4. Using other driving systems
2
When driving
●When the lane lines cannot be recognized while driving.
●The wiper switch is set on “LO” or “HI” mode or is set on “AUTO” mode with
wipers operating at low or high speed.
●The no-handed driving warning activates while the lane keeping assist function
is active. (The buzzer will beep twice.)
●When the lane departure warning function is activated.
Once the lane departure warning function is activated, it will be temporarily
canceled and resume a few seconds later.
■No-handed driving warning
If the steering wheel is not operated for about 15 seconds on a straight road or
about 5 seconds on a curve, the buzzer will beep twice, indicators on the multi-
information display will flash, and the lane keeping assist function will be temporarily
canceled. If you drive the vehicle with your hands lightly touching the steering
wheel, this may also be detected as no-handed driving.
■When the vehicle has been parked in the sun
The LKA system functions may not be available for a while after driving has started.
In such cases, turn the LKA system off and turn it on again after normal temperature
returns. When the temperature in the cab in decreases and the temperature around
the camera sensor becomes suitable for it s operation, the functions will begin to
operate.
■Warning lights and messages for LKA
Warning lights and messages are used to in dicate a system malfunction or to inform
the driver of the need for caution while driving. ( P. 4 9 9 , 5 1 1 )

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2-4. Using other driving systems
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from over-
heating when there is frequent steering input over an extended period of time. The
steering wheel may feel heavy as a result. Should this occur, refrain from excessive
steering input or stop the vehicle and turn the hybrid system off. The EPS system
should return to normal within 10 minutes.
CAUTION
■The ABS does not operate effectively when
●Tires with inadequate gripping ability ar e used (such as excessively worn tires on
a snow covered road).
●The vehicle hydroplanes while driving at high speed on wet or slick road.
■Stopping distance when the ABS is operating will exceed that of normal condi-
tions
The ABS is not designed to shorten the vehicle’s stopping dist ance. Always main-
tain a safe distance from the vehicle in front of you in the following situations:
●When driving on dirt, gravel or snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes or roads with uneven surfaces
■TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC system is operating.
Do not drive the vehicle in conditions where stability and power may be lost.
■When the VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■When the TRAC/VSC systems are turned off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are the systems to ensure vehicle stability and driving force, do not turn the
TRAC/VSC systems off unless necessary.

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2-4. Using other driving systems
Pre-Collision System
: If equipped
When the radar sensor detects possibilit y of a frontal collision, the pre-col-
lision system such as the brakes and seat belts are automatically engaged
to lessen impact and injuries to occupants as well as vehicle damage.
■Pre-collision seat belts (front seat belts 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 driver makes an emergency braking or loses
control of the vehicle. ( P. 7 5 )
However, when the VSC system is disabled, the system will not operate in
the event of skidding.
■ 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 possibility of a frontal collision, the system warns the
driver using a warning light, warning display* and buzzer. If the system
determines that a collision is unavoidable, the brakes are automatically
applied to reduce the collision speed. Pre-collision braking can be dis-
abled using the pre-collision braking off switch.
*: When the pre-collision braking system activates, “BRAKE!” will appear on the multi-information display and head-up display (if equipped), and
the warning light will begin flashing rapidly. ( P. 5 1 4 )
■Driver monitor system (if equipped)
When the system determines that there is a possibility of a frontal collision,
and the driver is not facing forward, PCS warnings are given in advance to
warn the driver. If the driver continue s to be not facing forward, and a high
possibility of a frontal collision is dete cted, PCS informs the driver of high
possibility of a frontal collision by perf orming slight braking to provide a
physically warning (pre-collision alert braking). ( P. 2 3 8 )

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2-4. Using other driving systems
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When driving
Disabling pre-collision brakingPre-collision braking disabled
Pre-collision braking enabled
The “PCS” warning light will
turn on when pre-collision brak-
ing is disabled.
Radar sensorThe radar sensor detects vehicles
or other obstacles on or near the
road ahead and determines
whether a collision is imminent
based on the position, speed, and
heading of the obstacles.
For vehicles equipped with the lane
keeping assist, in addition to the
radar sensor, the vehicle uses a
lane recognition camera in order
to determine whether or not a colli-
sion is likely to occur. ( P. 2 2 8 )