2015 Lexus IS250 brake

2434-5. Using the driving support systems
4
Driving
IS350/250_U (OM53C50U)
■VGRS is disabled when
VGRS may stop operating in the following situations.
In this event, the steering wheel may move from its straight forward position, but it will
return when the system restarts.
●When the steering wheel is operated for an extended period of time while the vehicle is
stopped or is moving very slowly
●When the steering wheel has been held fully to the left or right
The center position of the steering wheel may change when VGRS is disabled. However,
the position will return to normal after VGRS is reactivated.
■When the battery is disconnected
The steering wheel may move fr om its straight forward position, but this will be corrected
automatically when driving.
■Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC, hill-start assist
control and VGRS systems
●A sound may be heard from the engine compartment when the brake pedal is
depressed repeatedly, 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 sys-
tems.
●Any of the following condit ions may occur when the above systems are operating.
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 slig htly after the ABS is activated.
• The brake pedal may move down s lightly after the ABS is activated.
■EPS and VGRS operation sound
When the steering wheel is operated, a motor sound may be heard. This does not indi-
cate a malfunction.
■Reactivation of the TRAC/VSC systems
Even after the TRAC/VSC systems have been turned off, turning the engine off and then
on again will automatically reactivate the TRAC/VSC systems.
■Reactivation of the TRAC system linked to vehicle speed
When only the TRAC system is turned off, the TRAC system will turn on when vehicle
speed increases. However, when both TRAC /VSC systems are turned off, the systems
will not turn on even when vehicle speed increases.

2444-5. Using the driving support systems
IS350/250_U (OM53C50U)
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system 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 of f. The EPS system should return to normal
within 10 minutes.
■Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate:
●The shift lever is in a position other than P or N (when starting off forward/backward on
an upward incline).
●The vehicle is stopped.
●The accelerator pedal is not depressed.
●The parking brake is not engaged.
■Automatic system cancelation of hill-start assist control
The hill-start assist control will turn off in any of the following situations:
●The shift lever is moved to P or N.
●The accelerator pedal is depressed.
●The parking brake is engaged.
●Approximately 2 seconds elapse after the brake pedal is released.

2454-5. Using the driving support systems
4
Driving
IS350/250_U (OM53C50U)
CAUTION
■The ABS does not operate effectively when
●The limits of tire gripping performance have been exceeded (such as excessively
worn tires on a snow covered road).
●The vehicle hydroplanes while driving at high speed on wet or slick roads.
■Stopping distance when the ABS is operating may exceed that of normal conditions
The ABS is not designed to shorten the vehicle’s stopping distance. Always maintain a
safe distance from the vehicle in front of you, especially 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 uneven surfaces
■TRAC may not operate effectively when
Directional control and power may not be achievable while drivin g on slippery road
surfaces, even if the TRAC system is operating.
Drive the vehicle carefully in conditions where stability and power may be lost.
■Hill- start assist control does not operate effectively when
●Do not overly rely on hill-start assist contro l. Hill-start assist control may not operate
effectively on steep inclines and roads covered with ice.
●Unlike the parking brake, hill-start assist control is not intended to hold the vehicle
stationary for an extended period of time. Do not attempt to use hill-start assist con-
trol to hold the vehicle on an incline, as doing so may lead to an accident.
■When the VSC is activated
The slip indicator light flashes. Always drive carefully. Reckless driving may cause an
accident. Exercise particular care when the indicator light flashes.
■When the TRAC/VSC systems are turned off
Be especially careful and drive at a speed ap propriate to the road conditions. As these
are the systems to help ensure vehicle st ability and driving force, do not turn the
TRAC/VSC systems off unless necessary.
■Replacing tires
Make sure that all tires are of the specified size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire infla-
tion pressure level.
The ABS, TRAC and VSC systems will not function correctly if different tires are
installed on the vehicle.
Contact your Lexus dealer for further information when replacing tires or wheels.
■Handling of tires and the suspension
Using tires with any kind of problem or modi fying the suspension will affect the driving
assist systems, and may caus e a system to malfunction.

2464-5. Using the driving support systems
IS350/250_U (OM53C50U)
◆ Pre-collision warning
When a high possibility of a frontal
collision is detected, the pre-colli-
sion system warning light flashes, a
buzzer sounds and a message is
shown on the multi-information dis-
play to urge the driver to take eva-
sive action.
◆Pre-collision brake assist
When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to ho w strongly the brake pedal is depressed.
The system may not warn the driver using a warning light, warning display and
buzzer when the system detects and judges braking operations.
◆Pre-collision braking
When there is a high possibility of a frontal collision, the system warns the
driver using a warning light, warning di splay and buzzer. If the system deter-
mines that a collision is unavoidable, the brakes are automatically applied to
reduce the collision speed.
◆Suspension control (vehicles with Ad aptive Variable Suspension System)
When the system determines that there is a high possibility of a frontal colli-
sion, the operation of Adaptive Variable Suspension System ( P. 2 4 1 ) o p t i -
mally controls the damping force of the shock absorber.
PCS (Pre-Collision System)

: If equipped
When the radar sensor detects the possibility of a frontal collision, brakes are
automatically engaged to lessen im pact as well as vehicle damage.
The pre-collision system can be turned on and off as necessary by operating
the switch. ( P. 2 4 7 )

2484-5. Using the driving support systems
IS350/250_U (OM53C50U)
■The pre-collision system is operational when
The PCS OFF switch is not pressed and the following conditions are met:
●Pre-collision warning:
• Vehicle speed is greater th an about 10 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 10 mph (15 km/h).
●Pre-collision brake assist:
• The VSC OFF switch is not pressed.
• Vehicle speed is greater than about 19 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running
ahead of you is greater than about 19 mph (30 km/h).
• The brake pedal is depressed.
●Pre-collision braking:
• The VSC OFF switch is not pressed.
• Vehicle speed is greater th an about 10 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 10 mph (15 km/h).
●Suspension control (vehicles with Ad aptive Variable Suspension System):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greater than about 19 mph (30 km/h).
■Conditions that may trigger the system even if there is no danger of a collision
●When there is an object by the ro adside 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 a grade separation/interchange, sign, billboard, or other structure appears to be
directly in the vehicle’s line of travel
●When there is a metal plate in the road in front of the vehicle on a downhill slope
●When climbing a steep hill causes an over head billboard or other metallic structure to
appear directly in the vehicle’s line of travel
●When driving under an overpass
●When an extreme change in vehicle height occurs
●When passing through certain toll gates
●When passing through a tunnel
●When the radar sensor moves off position due to its surrounding area being subjected
to a strong impact
When the system is activated in the situations described above, there is also a possibility
that the brakes will be applied with a force greater than normal.

2514-5. Using the driving support systems
4
Driving
IS350/250_U (OM53C50U)
CAUTION
■Limitations of the pre-collision system
Do not overly rely on the pre-collision system. Always drive safely, taking care to
observe your surroundings and checking for any obstacles or other road hazards.
Failure to do so may cause an accident resulting in death or serious injury.
■Handling the radar sensor
Observe the following to ensure the pre-collision system can function effectively.
Otherwise, the system may not function correctly and could result in an accident.
●Keep the sensor and grille cover clean at all times.
Clean the sensor and grille cover with a soft cloth so you do not mark or damage
them.
●Do not subject the sensor or surrounding area to a strong impact.
If the sensor moves even slightly off positi on, the system may malfunction. If the sen-
sor or surrounding area is subject to a stro ng impact, always have the area inspected
and adjusted by your Lexus dealer.
●Do not disassemble the sensor.
●Do not attach accessories or stickers to the sensor, grille cover or surrounding area.
●Do not modify or paint the sensor and grille cover.
●Do not replace them with non-genuine parts.
■Cautions regarding the assist contents of the system
By means of alarms and brake control, the pre- collision system is intended to assist the
driver in avoiding collisions through the process of LOOK-JUDGE-ACT. There are
limits to the degree of assistance the system can provide, so please keep in mind the
following important points.
●Assisting the driver in watching the road
The pre-collision system is only able to detect obstacles directly in front of the vehicle,
and only within a limited range. It is not a mechanism that allows careless or inatten-
tive driving, and it is not a system that can assist the driver in low-visibility conditions. It
is still necessary for the driver to pay cl ose attention to the vehicle’s surroundings.
●Assisting the driver in making correct judgment
When attempting to estimate the possibility of a collision, the only data available to
the pre-collision system is that from obstacle s it has detected directly in front of the
vehicle. Therefore, it is absolutely necess ary for the driver to remain vigilant and to
determine whether or not there is a possib ility of collision in any given situation.
●Assisting the driver in taking action
The pre-collision system’s braking assist feat ure is designed to help reduce the sever-
ity of a collision, and so only acts when the system has judged that a collision is
unavoidable. This system by itself is not capable of automatically avoiding a collision
or bringing the vehicle to a stop safely. For this reason, when encountering a danger-
ous situation the driver must take direct and immediate action in order to ensure the
safety of all involved.

260
IS350/250_U (OM53C50U)4-6. Driving tips
●Use fluids that are appropriate to the prevailing outside temperatures.
•Engine oil
• Engine coolant
• Washer fluid
●Have a service technician inspect the condition of the battery.
●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 brand, and that chains match the size
of the tires.
*: Tire chains cannot be mounted on the 18-inch tires.
Perform the following according to the driving conditions:
●Do not try to forcibly open a window or move a wiper that is frozen. Pour
warm water over the frozen area to melt the ice. Wipe away the water imme-
diately 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.
●Check for and remove any excess ice or snow that may have accumulated on
the exterior lights, vehicle’s roof, chassis, around the tires or on the brakes.
●Remove any snow or mud from the bottom of your shoes before getting in the
vehicle.
Accelerate the vehicle slowly, keep a safe distance between you and the vehicle
ahead, and drive at a reduced speed suitable to road conditions.
Winter driving tips
Carry out the necessary preparations and inspections before driving the vehi-
cle in winter. Always drive the vehicle in a manner appropriate to the prevail-
ing weather conditions.
Preparation for winter
Before driving the vehicle
When driving the vehicle

2614-6. Driving tips
4
Driving
IS350/250_U (OM53C50U)
Park the vehicle and move the shift lever to P without setting the parking brake.
The parking brake may freeze up, preventing it from being released. If necessary,
block the wheels to prevent inadvertent sliding or creeping.
Except vehicles with 18-inch tires
Use the correct tire chain size when mounting the tire chains.
Chain size is regulated for each tire size.
Side chain
(0.12 in. [3 mm] in diameter)
Cross chain
(0.16 in. [4 mm] in diameter)
Vehicles with 18-inch tires
Tire chains cannot be mounted.
Snow tires should be used instead.
Regulations regarding the use of tire chains vary depending on location and type
of road. Always check local regulations before installing chains.
■Tire chain installation
Observe the following precautions wh en installing and removing chains:
●Install and remove tire chains in a safe location.
●Install tire chains on the rear tires. Do not install tire chains on the front tires.
●Install tire chains on rear tires as tightly as possible. Retighten chains after driving 1 /4
 1 /2 mile (0.5  1.0 km).
●Install tire chains following the instru ctions provided with the tire chains.
When parking the vehicle
Selecting tire chains
1
2
Regulations on the use of tire chains