engine Lexus IS250 2008 Repair Manual

157
2-4. Using other driving systems
2
When driving
08_IS350/250_U_(L/O_0708)
■Changing the vehicle- to-vehicle distance
Each push of the switch changes
the vehicle-to-vehicle distance
Long
Medium
Short
The vehicle-to-vehicle distance
is automatically set to the long
mode when the “ENGINE
START STOP” switch is
switched to IGNITION ON
mode.
A mark will be displayed to indi-
cate the presence of the vehicle
if a vehicle is running ahead of
you.
Preceding
vehicle mark

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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
2
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
08_IS350/250_U_(L/O_0708)
■Hill-start assist control is operational when
●The shift lever is in the D or S position.
●The brake pedal is not depressed.
■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating 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 engine OFF. The system should return to normal within
10 minutes.
CAUTION
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded.
●The vehicle hydroplanes while driving at high speed on the 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 distance. 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 roads

183
2-5. Driving information
2
When driving
08_IS350/250_U_(L/O_0708)
Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■Pre-winter preparations
● Use fluids that are appropriate to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
• Have a service technician inspect the level and specific gravity
of battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the rear tires.
Ensure that all tires are the specified size and the same brand, and that
chains match the size of the tires.
■Before driving the vehicle
Perform the following according to the driving conditions.
● Do not try to forcibly open a window or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To ensure proper operation of the climate control system fan,
remove any snow that has accumulated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumulated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.

189
2-5. Driving information
2
When driving
08_IS350/250_U_(L/O_0708)
Dinghy towing (vehicles with a manual transmission)
Towing your vehicle with 4 wheels on the groundTo prevent damage to your vehicle, perform the following procedures
before towing. Shift the shift lever to neutral.
Switch to ACCESSORY mode. ( →P. 1 1 9 )
Ensure that the audio system and other powered devices have been
turned OFF.
Release the parking brake.
After towing, leave the engine in idle for at least 3 minutes before driv-
ing the vehicle.
■Necessary equipment and accessories
Specialized equipment and accessories are required for dinghy towing. Contact
the service branch of the motor home manufacturer regarding recommended
equipment.
Your vehicle can be dinghy towed in a forward direction (with 4 wheels on
the ground) behind a motor home.
STEP1
STEP2
STEP3

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2-5. Driving information
08_IS350/250_U_(L/O_0708)
NOTICE
■Dinghy towing direction
■To prevent the steering from locking
Ensure the “ENGINE START STOP” switch is in ACCESSORY mode.
Do not tow the vehicle backwards.
Doing so may cause serious damage.

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3-1. Using the air conditioning system and defogger
3
Interior features
08_IS350/250_U_(L/O_0708)
CAUTION
■To prevent the windshield from fogging up
Do not use during cool air operation in extremely humid weather. The dif-
ference between the temperature of the outside air and that of the windshield can
cause the outer surface of the windshield to fog up, blocking your vision.
NOTICE
■To prevent battery discharge
Do not leave the automatic air conditioning system on longer than necessary when
the engine is stopped.