brakes Lexus IS F 2008 Do-It-Yourself Maintenance /

170
2-4. Using other driving systems
■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.
■LSD function
The LSD function is part of TRAC control. It maintains drive power by applying the
brakes to wheels that spin when accelerating during a turn, and operates even
when TRAC or TRAC/VSC operation is turned off. However, it will not operate
when the rear brakes are at a high temperature.
■Hill-start assist control is operational when
●The shift lever is in the D or M position.
●The brake pedal is not depressed.
■EPS operation sound
When the steering wheel operates, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
■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. Th e system should return to normal within
10 minutes.
■Automatic deactivation of “Sport” mode
When the “ENGINE START STOP” switch is turned OFF after driving in “Sport”
mode, the mode is automatically deactivated.

173
2-4. Using other driving systems
2
When driving
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 help lessen impact and inju ries to occupants as well as vehicle
damage when the radar sensor detect s an unavoidable frontal collision.
■Pre-collision seat belts
The seat belts are immediately retracted as the effect of the pretensioner is
increased ( P. 52), to provide even greate r 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.

174
2-4. Using other driving systems
■The pre-collision system is operational when
●Pre-collision 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 about 18 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (linked to brake operation)
• Vehicle speed exceeds 18 mph (30 km/h).
• The system detects sudd en braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision 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. 350, 360)

180
2-5. Driving information
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 appropria te 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.
Ensure that all tires are the specified size and the same brand.
■Before driving the vehicle
Perform the following according to the driving conditions.
● Do not try to forcibly open a w indow 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 accumu lated on the air inlet vents in
front of the windshield.
● Remove any ice that has accumul ated 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.

273
4-2. Maintenance
4
Maintenance and care
Vehicle interior
ItemsCheck points
Accelerator pedal• Moves smoothly (without uneven pedal effort or catching)?
Automatic transmission “Park”
mechanism• Can the vehicle be held securely on an incline with the shift lever in
P?
Brake pedal
• Moves smoothly?
• Does it have appropriate clearance and correct amount of free play?
Brakes
• Not pull to one side when applied?
• Loss of brake effectiveness?
• Spongy feeling brake pedal?
• Pedal almost touches floor?
Head restraints• Move smoothly and lock securely?
Indicators/buzzers• Function properly?
Lights
• Do all the lights come on?
• Headlights aimed correctly? ( P. 3 3 2 )
Pa r k i n g b r a ke
• Moves smoothly?
• Can hold the vehicle securely on
an incline?
Seat belts
• Does the seat belt system operate smoothly?
• Are the belts undamaged?
Seats• Do the seat controls operate prop- erly?

340
5-1. Essential information
If your vehicle needs to be towed
Before towingThe following may indicate a problem with your transmission. Contact
your Lexus dealer before towing.
● The engine is running, but the vehicle will not move.
● The vehicle makes an abnormal sound.
Emergency towing
If a tow truck is not available, in an emergency your vehicle may be tem-
porarily towed using a cable or chain secured to the emergency towing
eyelet. This should only be attempted on hard, surfaced roads for short
distances at low speeds.
A driver must be in the vehicle to s teer and operate the brakes. The vehi-
cle’s wheels, drive train, axles, steering and brakes must be in good condi-
tion.
Towing eyelet
If towing is necessary, we recommend having your vehicle towed by your
Lexus dealer or a commercial towing se rvice, using a lift-type truck or a flat
bed truck.
Use a safety chain system for all towi ng, and abide by all state/provincial
and local laws.
If towing from the rear, the vehicle’s front wheels and axles must be in good
condition. ( P. 344)
If they are damaged, use a to wing dolly or flat bed truck.

5
When trouble arises
341
5-1. Essential information
■Emergency towing procedureRelease the parking brake.
Shift the shift lever to N.
Put the “ENGINE START STOP” switch in ACCESSORY mode (engine
off) or IGNITION ON mode (engine running).
CAUTION
■Caution while towing
●Use extreme caution when towing the vehicle.
Avoid sudden starts or erratic driving maneuvers which place excessive stress on
the emergency towing eyelet and the cables or chains.
●If the engine is not running, the power assi st for the brakes and steering will not
function, making steering and braking more difficult.
NOTICE
■To prevent causing serious damage to the transmission
Never tow this vehicle from the rear with four wheels on the ground. This may cause
serious damage to the transmission.
STEP1
STEP2
STEP3

5
When trouble arises
357
5-2. Steps to take in an emergency
CAUTION
■If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could cause loss of
vehicle control and result in death or serious injury.
●Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pres-
sure immediately.
●If the tire pressure warning light comes on even after tire inflation pressure adjust-
ment, it is probable that you have a flat tire. Check the tires. If the tire is flat,
change to the spare tire and have the flat tire repaired by the nearest Lexus
dealer.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could
lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

5
When trouble arises
369
5-2. Steps to take in an emergency
Wa r n i n g m e s s a g eDetailsCorrection procedure
(Flashing and then con-tinuously on)
(Flashing)
(If equipped)Indicates that the radar
cruise control system is
unable to judge vehicle-
to-vehicle distance.
• Switch the driving mode to either the “Normal” or
“Sport” mode.
• If the windshield wipers
are on, turn them off or
set them to either the
intermittent or the slow
mode.
(Flashing)
(If equipped)
Indicates that your vehi-
cle is nearing the vehicle
ahead (in radar cruise
mode).
Slow the vehicle by apply-
ing the brakes.
■Changing the engine oil (U.S.A. only)
Make sure to reset the oil change system. ( P. 2 8 4 )
■Warning light display in radar cruise mode (if equipped)
In the following cases, the warning light may not be displayed even if vehicle-to-
vehicle distance decreases.
●When your vehicle and the vehicle ahead are traveling at the same speed or the
vehicle ahead is traveling more quickly than your vehicle
●When the vehicle ahead is traveling at a very low speed
●Immediately after cruise control speed is set
●At the instant the accelerator pedal is depressed

372
5-2. Steps to take in an emergency
Once
(Comes on for 10 seconds.)
(Flashing)
Indicates that the
key battery is low.Replace the bat-
tery. (P. 3 1 6 )

Indicates that the
“ENGINE START
STOP” switch has
been turned
twice to ACCES-
SORY mode
without starting
the engine when
a closed door is
opened.
Press the
“ENGINE START
STOP” switch
while applying the
brakes.

(Flashing)
Indicates that the
steering lock has
not released
within 3 seconds
of pressing the
“ENGINE START
STOP” switch.Press the
“ENGINE START
STOP” switch
again while turn-
ing the steering
wheel with the
brake pedal
depressed.
Interior
buzzerExterior buzzerWa r n i n g m e s s a g eDetailsCorrection
procedure