light Lexus IS250 2008 Workshop Manual

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08_IS350/250_U_(L/O_0708)
2-4. Using other driving systems
Cruise control (if equipped)
Use the cruise control to maintain a set speed without using the accelera-
tor.
■ Set the vehicle speed
Turn the “ON-OFF” button on.
Push the button once more to
deactivate the cruise control.
Accelerate or decelerate to the
desired speed and press the
lever down to set the cruise
control speed.
■ Adjusting the speed setting
Increase speed
Decrease speed
Hold the lever until the desired
speed setting is obtained.
Fine adjustment of the set
speed (approximately 1.0 mph
[1.6 km/h]) can be made by
lightly pressing the lever up or
down and releasing it.
STEP1
STEP2

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2-4. Using other driving systems
08_IS350/250_U_(L/O_0708)
■If the cruise control indicator light flashes
Turn the “ON-OFF” button off once, and then reactivate the system.
If the cruise control speed cannot be set or if the cruise control cancels immediately
after being activated, there may be a malfunction in the cruise control system. Have
the vehicle inspected by your Lexus dealer.
CAUTION
■To avoid operating the cruise control by mistake
Keep the “ON-OFF” button off when not in use.
■Situations unsuitable for cruise control
Do not use cruise control in any of the following situations.
Doing so may result in control of the vehicle being lost and could cause serious or
fatal accident.
●In heavy traffic
●On roads with sharp bends
●On slippery roads, such as those covered with rain, ice or snow
●On steep hills
●On winding roads

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2-4. Using other driving systems
08_IS350/250_U_(L/O_0708)
■Driving in the selected cruise control mode
Accelerate or decelerate to the
desired speed and press the
lever down to set.
■ Adjusting the speed setting
Increase speed
Decrease speed
Hold the lever until the desired
speed setting is displayed.
In the constant speed control
mode, fine adjustment of the set
speed (approximately 1.0 mph
[1.6 km/h]) can be made by
lightly pressing the lever up or
down and releasing it.
■Canceling and resuming the speed setting
Cancel
Push the lever towards you to
cancel cruise control.
The setting is also canceled
when the brakes are applied.
Resume
To resume cruise control and
return to the set speed, push the
lever up.

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2-4. Using other driving systems
2
When driving
08_IS350/250_U_(L/O_0708)
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): Wh en the speed is set to
62 mph (100 km/h) and the vehicle 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 used 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 approximately 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.

168
2-4. Using other driving systems
08_IS350/250_U_(L/O_0708)
■Sensor detection information
●Certain vehicle conditions and the surrounding environment may affect the
ability of the sensor to correctly detect obstacles. Particular instances where this
may occur are listed below.
• There is dirt, snow or ice on the sensor.
• The sensor is frozen.
•The sensor is covered in any way.
• The vehicle is leaning considerably to one side.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• The vicinity of the vehicle is noisy due to vehicle horns, motorcycle engines,air brakes of large vehicles, or other loud noises producing ultrasonic waves.
• There is another vehicle equipped with parking assist sensors in the vicinity.
• The sensor is coated with a sheet of spray or heavy rain.
• The vehicle is equipped with a fender pole or wireless antenna.
• Towing eyelets are installed.
• The bumper or sensor receives a strong impact.
• The vehicle is approaching a tall or curved curb.
• In harsh sunlight or intense cold weather
In addition to the examples above, there are instances in which, because of their
shapes, signs and other objects may be judged by the sensor to be closer than they
are.
●The shape of the obstacle may prevent the sensor from detecting it. Pay particu-
lar attention to the following obstacles.
• Wires, fences, ropes etc.
• Cotton, snow and other materials that absorb radio waves
• Sharply-angled objects
• Low obstacles
• Tall obstacles with upper sections projecting outwards in the direction of your
vehicle
■When the display flashes and a message is displayed
→P. 3 6 9
■Certification (Canada only)
This ISM device compiles with Canadian ICES-001.

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2-4. Using other driving systems
2
When driving
08_IS350/250_U_(L/O_0708)
When the VSC/TRAC/hill-start assist control systems are operatingIf the vehicle is in danger of slip-
ping, rolling backwards when
starting on an incline, or if the rear
wheels (2WD) or 4 wheels
(AWD) spin, the slip indicator light
flashes to indicate that the VSC/
TRAC/hill-start assist control sys-
tems have been engaged.
A buzzer (intermittent) sounds to
indicate that VSC is operating.
The stop lights and high mounted
stoplight turn on when the hill-start
assist control system is operating.
■VDIM (Vehicle Dynamics Integrated Management) (IS350)
Provides integrated control of the ABS, brake assist, TRAC, VSC, hill-start
assist control, and EPS systems.
Maintains vehicle stability when swerving on slippery road surfaces by
controlling the brakes and engine output.
■PCS (Pre-Collision System) (if equipped)
→P. 1 76

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2-4. Using other driving systems
08_IS350/250_U_(L/O_0708)
To disable TRAC and/or VSCIf the vehicle gets stuck in fresh snow or mud, TRAC and VSC may
reduce power from the engine to the wheels. You may need to turn the
system off to enable you to rock the vehicle in order to free it.
■ Turning off TRAC
Quickly push and release the but-
ton to turn off TRAC.
The slip indicator light should come
on.
Push the button again to turn the
system back on.
■Turning off TRAC and VSC
Push and hold the button for more
than 3 seconds while the vehicle is
stopped to turn off TRAC and
VSC.
The slip indicator light and “VSC
OFF” indicator light should come
on.
Push the button again to turn the
system back on.

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2-4. Using other driving systems
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When driving
08_IS350/250_U_(L/O_0708)
■Automatic reactivation of TRAC and VSC
Turning the “ENGINE START STOP” switch OFF after turning off the TRAC and
VSC systems will automatically re-enable them.
■Automatic TRAC reactivation
If only the TRAC system is turned off, the TRAC system will turn on when vehicle
speed increases.
■Automatic TRAC and VSC reactivation
If the TRAC and VSC systems are turned off, the systems will not turn on even when
vehicle speed increases.
■Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and hill-start
assist control systems
●A sound may be heard from the engine compartment when the engine is
started or just after the vehicle begins to move. This sound does not indicate that
a malfunction has occurred in any of these systems.
●Any of the following conditions may occur when the above systems are operat-
ing. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.

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2-4. Using other driving systems
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When driving
08_IS350/250_U_(L/O_0708)
CAUTION
■TRAC may not operate effectively when
Directional control and power may not be achievable 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.
■If hill-start assist control does not operate effectively
(vehicles with an automatic transmission)
The hill-start assist control may not operate effectively on steep inclines and roads
covered in ice.
■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 TRAC and VSC are off
Be especially careful and drive at a speed appropriate to the road conditions. As
there are systems to ensure vehicle stability and driving force, do not turn off TRAC
and VSC unless necessary.
■Replacing tires
Make sure that all tires are of the same size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire
pressure level.
The ABS and VSC systems will not function correctly if different tires are fitted on
the vehicle.
Contact your Lexus dealer for further information when replacing tires or wheels.
■Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will affect the driv-
ing assist systems, and may cause the system to malfunction.

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2-4. Using other driving systems
2
When driving
08_IS350/250_U_(L/O_0708)
■The pre-collision system is operational when
●Seat belt (linked to the radar sensor)
• Vehicle speed is above 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncomingvehicle exceeds 18 to 24 mph (30 to 40 km/h).
• The front occupants are wearing a seat belt.
●Seat belts (linked to brake operation)
• Vehicle speed exceeds 9 mph (15 km/h).
• The system detects sudden braking or skidding.
• The front occupants are wearing a seat belt.
●Brake Assist
• Vehicle speed is above 18 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle is greater than 18 to 24 mph (30 to 40 km/h).
• The brake pedal is depressed.
■Conditions that may trigger the system even if there is no danger of 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 retract 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.
■When there is a malfunction in the system
Warning lights and/or warning messages will turn on or flash. (
→P. 360, 369)