2007 Lexus IS250 automatic transmission

148
2-4. Using other driving systems
Driving assist systems
To help enhance driving safety and performance, the following systems
operate automatically in response to various driving situations. Be aware,
however, that these systems are supplementary and should not be relied
upon too heavily when operating the vehicle.
■ABS (Anti-lock Brake System)
Restrains the vehicle from slipping when driving on slick road surfaces or
in the event of sudden braking.
■BA (Brake Assist)
Generates an increased level of braking force after the brake pedal is
depressed, when the system detects a panic stop situation.
■VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or turning on
slippery road surfaces.
■TRAC (Traction Control)
Maintains drive power and prevents the rear wheels (2WD models) or all
wheels (4WD models) from spinning when starting the vehicle or acceler-
ating on slippery roads.
■Hill-start assist control (vehicles with an automatic transmission)
Prevents the vehicle from rolling backwards when starting on an incline or
slippery slope.
■EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.

153
2-4. Using other driving systems
2
When driving
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.
■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.

162
2-5. Driving information
Selecting snow chains
Snow chains can be mounted on 16- and 17-inch tires. They cannot be
mounted on 18-inch tires. Use the correct snow chain size when mount-
ing the snow chains. Chain size is regulated for each tire sizes.
Side chain
(0.12 in. [3 mm] in diameter)
Cross chain
(0.16 in. [4 mm] in diameter)
Regulations on the use of snow chains
●Regulations regarding the use of tire chains vary according to location
and type of road. Always check local regulations before installing
chains.
●Install the chains on the rear tires.
●Retighten the chains after driving 1 /4 - 1 /2 mile (0.5 - 1.0 km).
■When driving the vehicle
Accelerate the vehicle slowly and drive at a reduced speed suitable to
road conditions.
■When parking the vehicle
Park the vehicle and move the shift lever to P (automatic transmis-
sion) or R (manual transmission) without setting the parking brake.
The parking brake may freeze up, preventing it from being released.

166
2-5. Driving information
Dinghy towing (vehicles with an automatic transmission)
NOTICE
■To avoid serious damage to your vehicle
Do not tow your vehicle with four wheels on the ground.
Your vehicle is not designed to be dinghy towed (with 4 wheels on the
ground) behind a motor home.

228
3-5. Other interior features
Seat heaters (if equipped)
■The seat heaters can be used when
The engine switch is in IG-ON mode.
■When not in use
Set the dial to 0. The indicator light turns off.
Heats the seats
The indicator light comes on.
The higher the number, the
warmer the seats become.
Vehicles with an automatic
transmission
Heats the seats
The indicator light comes on.
The higher the number, the
warmer the seats become.
Vehicles with a manual
transmission
Driver’s
seatFront
passenger’s
seat
Driver’s
seatFront
passenger’s
seat

230
3-5. Other interior features
Seat heaters and ventilators (if equipped)
■The seat heaters and ventilators can be used when
The engine switch is in IG-ON mode.
■When not in use
Set the dial to 0. The indicator light turns off.
The seat heaters and ventilators heat the seats and maintain good airflow
by blowing air from the seats.
Heats the seats
The indicator light (red) comes
on.
The higher the number, the
warmer the seats become.
Blows air from the seats
The indicator light (green)
comes on.
The higher the number, the
stronger the airflow becomes.
Heats the seats
The indicator light (red) comes
on.
The higher the number, the
warmer the seats become.
Blows air from the seats
The indicator light (green)
comes on.
The higher the number, the
stronger the airflow becomes.
Driver’s
seatFront
passenger’s
seat
Vehicles with an automatic
transmission
Driver’s
seatFront
passenger’s
seat
Vehicles with a manual trans-
mission

260
4-2. Maintenance
Vehicle interior
ItemsCheck points
Accelerator pedal• Moves smoothly (without uneven
pedal effort or catching)?
Automatic transmission “Park”
mechanism• Can the vehicle be hold 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 1 8 )
Parking brake
• 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?

316
4-3. Do-it-yourself maintenance
FuseAmpereCircuit
13FR DOOR RH20APower windows, outside rear view
mirrors
14AM215ASmart access system with push-button
start
15RH-IG7. 5 A
Seat belts, Lexus parking assist-sen-
sor, automatic transmission, seat
heater and ventilator
16FR S/HTR RH15ASeat heaters and ventilators
17ECU-IG RH10A
Power seats, smart access system with
push-button start, AWD system, out-
side rear view mirrors, VDIM, VSC,
air conditioning system, pre-collision
seat belt, electric tilt and telescopic
steering, power windows, navigation
system
■After a fuse is replaced
●If the lights do not turn on even after the fuse has been replaced, a bulb may
need replacement. (P. 3 1 9 )
●If the replaced fuse blows again, have the vehicle inspected by your Lexus
dealer.
■If there is an overload in the circuits
The fuses are designed to blow before the entire wiring harness is damaged.