2010 Lexus HS250h warning light

217
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 vehicl e 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 for 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. 205) is set with vehicle
speed above approx. 45 mph (approx . 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.

221
2-4. Using other driving systems
2
When driving
●The vehicle speed deviates from the operating range of the LKA system func-
tions.
●When the lane lines cannot be recognized while driving.
●Low speed or high speed wiper operation states. 
The buzzer may not beep when the LKA system functions are canceled
because the notification of dynamic radar cruise control cancellation takes pri-
ority over the LKA system and cancels the function.
●The no-handed driving warning activates while the lane keeping assist function
is active. (The buzzer will beep twice.)
■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 ar e used to indicate a system malfunction or to inform
the driver of the need for caution while driving. ( P. 493, 505)

228
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 are 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.

232
2-4. Using other driving systems
Pre-Collision System
: If equipped
When the radar sensor detects an unavoidable frontal collision, safety sys-
tems 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 roll up the seat belt before the collision occurs. 
The same will happen if the driver makes an emergency braking or loses
contr
ol of the vehicle. ( P. 74 )
However, when the TRAC/VSC systems are disabled, the system will not
oper
ate 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 button.
■ Driver monitor system (if equipped)
When the system determines that ther e is a possibility of a collision, and
the driver is not facing forward, PC S warnings are given in advance to
warn the driver. If the driver contin ues to be not facing forward, and a
probable collision is detected, PCS in forms the driver of danger by per-
forming slight braking to provide a physically warning (pre-collision alert
br
aking). ( P. 2 3 5)

233
2-4. Using other driving systems
2
When driving
Disabling pre-collision braking
Pre-collision braking disabled
Pre-collision braking enabled
The “PCS” warning light will
come on when pr
e-collision
braking is disabled.
Radar sensor
The radar sensor detects vehicles
or other obstacles on or near the
road ahead and determines
whether a collision is imminent
based on the posit ion, 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. 225)

235
2-4. Using other driving systems
2
When driving
●Pre-collision braking:
• The pre-collision braking off button is not pressed.
• Vehicle speed is greater than about 9 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greater than about 9 mph (15 km/h).
●Pre-collision alert braking (vehicle with driver monitor system):
• The pre-collision braking off button is not pressed.
• The system determines that the driver is not facing forward.
• Vehicle speed is greater than about 9 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greate r than about 24 mph (40 km/h).
■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 the system is activated in the situations described above, there is also a possi-
bility that the seat belts will roll up 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.
■When there is a malfunction in the system
Warning lights and/or warning messages will turn on or flash. ( P. 493, 502, 505)

432
4-3. Do-it-yourself maintenance
Washer fluid
If any washer does not work or the
warning message appears on the
multi-information display, the
washer tank may be empty. Add
washer fluid.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go down slightly as the brake pads wear out or
when the fluid level in the accumulator is high. 
If the reservoir needs frequent refilling, there may be a serious problem.
CAUTION
■When adding washer fluid
Do not add washer fluid when the hybrid system is hot or operating as washer fluid
contains alcohol and may catch fire if spilled on the engine etc.
NOTICE
■Do not use any fluid other than washer fluid
Do not use soapy water or engine antifreeze instead of washer fluid. 
Doing so may cause streaking on the vehicle’s painted surfaces.
■Diluting washer fluid
Dilute washer fluid with water as necessary. 
Refer to the freezing temperatures listed on the washer fluid tank.

439
4-3. Do-it-yourself maintenance
4
Maintenance and care
■How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the “POWER” switch off.
Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to the specified cold tire inflation
pressure level. ( P. 555 )
Make sure to adjust the tire pressure to the specified cold tire inflation
pressure level. The tire pressure warning system will operate based on
this pressure level.
Turn the “POWER” switch to ON mode.
Press and hold the tire pressure warning reset switch until the tire
pressure warning light flashes slo
wly 3 times and the message
“TIRE PRESSURE RESET PROC EEDING” appears on the
multi-information display.
Wait for a few minutes with th e “P
OWER” switch in ON mode
and then turn the “POWER” switch off.
Registering ID codes
The tire pressure warning valve and transmitter is equipped with a unique
ID code. When replacing a tire pressure warning valve and transmitter, it
is necessary to register the ID code. Ha ve the ID code registered by your
Lexus dealer.