2008 Lexus IS250 speed sensor

144
2-3. Operating the lights and windshield wipers
AFS (vehicles with discharge headlights)AFS (Adaptive Front—lighting System) improves visibility at intersections
and on curves by automatically adjusting the level of the headlights
according to vehicle speed and the degree of the tire angle that are con-
trolled by steering input.
Operates at speeds of 6 mph (10 km/h) or higher.
■ Deactivating AFS
How to switch: P. 2 4 5
turns on when the AFS is deactivated.
■Daytime running light system
To make your vehicle more visible to other drivers, the headlights turn on automati-
cally (at a reduced intensity) whenever the engine is started and the parking brake
is released. Daytime running lights are not designed for use at night.
■Headlight control sensor
The sensor may not function 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.

148
2-3. Operating the lights and windshield wipers
■The windshield wiper and washer can be operated when
The “ENGINE START STOP” switch is in IGNITION ON mode.
■Effects of vehicle speed on wiper operation
Vehicle speed affects the following even when the wipers are not in “AUTO” mode.
●Intermittent wiper interval (“INT” mode)
●Wiper operation when the washer is being used (delay until drip prevention
wiper sweep occurs)
With “LO” selected, wiper operation will be switched from low speed to intermit-
tent wiper operation only when the vehicle is stationary.
(However, the mode cannot be switched wh en the adjustment dial for the intermit-
tent wiper interval is se t to the lowest setting.)
■Rain-sensing windshield wipers (if equipped)
With “AUTO” selected, the wipers will operate automatically when
the sensor detects falling rain. The system automatically adjusts
wiper timing in accordance with rain volume and vehicle speed.
Sensor sensitivity (low)
Sensor sensitivity (high)
Rain-sensing wiper operation
Low speed wiper operation
High speed wiper operation
Temporary operation
Wash/wipe operation
Wipers operate automatically.
(After operating several times,
the wipers operate one more
time after a short delay to pre-
vent dripping.)

158
2-4. Using other driving systems
Driving in vehicle-to-vehicle distance control mode This mode employs a radar sensor to detect the presence of vehicles
within 328 ft. (100 m) ahead and to judge the distance between your
vehicle and those vehicles.
Note that vehicle-to-vehicle distance will close when trave ling on long down-
hill slopes.
Example of constant speed cruising (when there are no vehicles
ahead): When set to 62 mph (100 km/h)
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehi-
cle distance can also be set by oper ating the vehicle-to-vehicle distance
switch.
Example of deceleration cruising (when the vehicle ahead is driving
slower than the set speed): When fixed speed cruising is set at 62 mph
(100 km/h) and the vehicle ahead is driving at 50 mph (80 km/h)
When a vehicle is detected running ahead of you, in the same lane, the sys-
tem automatically decelerates 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 on the vehicle ahead.
Example of follow-up cruising (when following a vehicle driving slower
than the set speed): When the speed is set to 62 mph (100 km/h) and
the vehicle ahead is driving at 50 mph (80 km/h)

159
2-4. Using other driving systems
2
When driving
The system continues follow-up cruising while adjusting for changes in the
speed of the vehicle ahead in order to maintain the vehicle-to-vehicle dis-
tance set by the driver.
Example of acceleration (when there are no longer vehicles driving
slower than the set speed in the lane ahead): When the speed is set to
62 mph (100 km/h) and the vehicl e ahead driving at 50 mph (80
km/h) is out of the lane
When the vehicle ahead of you executes a lane change, the system slowly
accelerates until the set vehicle speed is reached. The system then returns to
fixed speed cruising.
■Dynamic radar cruise control warning lights, messages and buzzers
Warning lights, messages and buzzers are us ed to indicate a system malfunction or
to alert you to the need for caution while driving. ( P. 3 6 9 )
■The dynamic radar cruise can be set when
●The shift lever is in D or the 4, 5 or 6 range of S.
●Vehicle speed is between approximatel y 30 mph (45 km/h) and 85 mph (135
km/h).
■Accelerating
The vehicle can be accelerated normally.
■Automatically canceling vehicle-to-vehicle distance control
Vehicle-to-vehicle distance control driving is automatically canceled in the follow-
ing situations.
●Vehicle speed falls below 25 mph (40 km/h)
●VSC is activated
●The sensor cannot operate correctly because it is covered in some way.
●The windshield wipers are operating at high speed.
●The “ECT SNOW” switch is set to snow mode.
If vehicle-to-vehicle distance control driving is automatically canceled for any other
reason, there may be a malfunction in the system. Contact your Lexus dealer.

160
2-4. Using other driving systems
■Automatically cancelling constant speed control
The set speed is automatically canceled in the following situations.
●Actual vehicle speed is more than 10 mph (16 km/h) below the preset vehicle
speed
At this time, the memorized set speed is not retained.
●Vehicle speed falls below 25 mph (40 km/h)
●VSC is activated
■Vehicle-to-vehicle distance settings
Select a distance from the table below. Note that the distances shown correspond
to a vehicle speed of 50 mph (80 km/h). Vehicle-to-vehicle distance increases/
decreases in accordance with vehicle speed.
■Radar sensor and grille cover
Always keep the sensor and grille cover clean to ensure that the vehicle-to-vehicle
distance control operates properly. (Some obstructions, such as snow, ice or plastic
objects, cannot be detected by the obstruction sensor.)
Dynamic radar cruise control is canc eled if an obstruction is detected.
Distance optionsVehicle-to-vehicle distance
LongApproximately 164 f t. (50 m)
MediumApproximately 132 ft. (40 m)
ShortApproximately 100 f t. (30 m)
Grille cover
Radar sensor

162
2-4. Using other driving systems
CAUTION
■Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise control in any of the following situations.
Doing so may result in inappropriate co ntrol of speed and could cause serious or
fatal accident.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as thos e covered with rain, ice or snow
●Where there are sudden changes between sharp up and down gradients
●At entrances to expressways
●When weather conditions are bad enough that they may prevent the sensors
from functioning correctly (f og, snow, sandstorm, etc.)
●Where buzzer can be heard often
■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 prox-
imity alarm ( P. 369) will not be activated, and an accident may result.
●Vehicles that cut in suddenly
●Vehicles traveling at low speeds
●Vehicles that are not moving
●Vehicles with small rear ends (tra ilers with no load on board etc.)
●Motorcycles traveling in the same lane

169
2-4. Using other driving systems
2
When driving
■Customization that can be configured at Lexus dealer
Settings (e.g. buzzer volume) can be changed. (Customizable features P. 4 3 6 )
CAUTION
■Caution when using the intuitive parking sensor
Observe the following precautions.
Failing to do so may result in the vehicle being unable to be driven safely and possi-
bly cause an accident.
●Do not use the sensor at speeds in excess of 6 mph (10 km/h).
●Do not attach any accessories within the sensor range.
NOTICE
■Notes when washing the vehicle
Do not apply intensive bursts of water or steam to the sensor area.
Doing so may result in the sensor malfunctioning.

176
2-4. Using other driving systems
PCS (Pre-Collision System) (if equipped)
Radar sensorDetects vehicles or other obsta-
cles on or near the road ahead and
determines whether a collision is
imminent based on the position,
speed, and heading of the obsta-
cles. Grille cover
Radar sensor
Safety systems such as the brakes and seat belts are automatically
engaged to lessen impact and injuries to occupants as well as vehicle dam-
age when the radar sensor detects an unavoidable frontal collision.
■Pre-collision seat belts
The seat belts are immediately retracted as the effect of the pretensioner is
increased ( P. 53), to provide even greater constraining force to protect
the driver and passengers. In the event of sudden braking or skidding, the
system will operate even if no obstacle has been detected.
■Pre-collision brake assist
Applies greater braking force in relati on to how strongly the brake pedal is
depressed.
■Obstacles not detected
The sensor cannot detect plastic obstacles such as pylons. There may also be occa-
sions when the sensor cannot detect pedestrians, animals, bicycles, motorcycles,
trees, or snowdrifts.