tires LEXUS GS300H 2019 User Guide

2854-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Before using LKA system
Do not rely solely upon the LKA system. Th e LKA system does not automatically drive the vehicle or reduce the amount of attention that must be paid to the area in front of
the vehicle. The driver must always assume full responsibility for driving safely by pay- ing careful attention to the surrounding conditions and operating the steering wheel tocorrect the path of the vehicle. Also, the driver must take adequate breaks when
fatigued, such as from driving for a long period of time. Failure to perform appropriate driving operat ions and pay careful attention may lead to an accident, resulting in death or serious injury.
■To avoid operating LKA system by mistake
When not using the LKA system, use the LKA switch to turn the system off.
■Situations unsuitable for LKA system
Do not use the LKA system in the following situations. The system may not operate properly and le ad to an accident, resulting in death or serious injury.
●A spare tire, tire chains, etc. are equipped.
●When the tires have been excessively worn, or when the tire inflation pressure is low.
●Tires which differ by structure, manufacturer, brand or tread pattern are used.
●Objects or patterns that could be mistaken for white (yellow) lines are present on the side of the road (guardrails, cu rbs, reflective poles, etc.).
●Vehicle is driven on a snow-covered road.
●White (yellow) lines are difficult to see due to rain, snow, fog, dust, etc.
●Asphalt repair marks, white (yellow) line marks, etc. are present due to road repair.
●Vehicle is driven in a temporary lane or restricted lane due to construction work.
●Vehicle is driven on a road surface which is slippery due to rainy weather, fallen snow, freezing, etc.
●Vehicle is driven in traffic lanes other than on highways and freeways.
●Vehicle is driven in a construction zone.
●Vehicle is towing a trailer or another vehicle. (vehicles with towing package)
■Preventing LKA system malfunctions and operations performed by mistake
●Do not modify the headlights or place stickers, etc. on the surface of the lights.
●Do not modify the suspension etc. If the suspension etc. needs to be replaced, con- tact any authorized Lexus retailer or Le xus authorized repairer, or any reliable
repairer.
●Do not install or place anything on the hood or grille. Also, do not install a grille guard (bull bars, kangaroo bar, etc.).
●If your windshield needs repairs, contac t any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer.

2904-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
●The vehicle is driven on a road which tilts left or right, or a winding road.
●The vehicle is driven on an unpaved or rough road.
●The vehicle is driven around a sharp curve.
●The traffic lane is excessively narrow or wide.
●The vehicle is extremely tilted due to carrying heavy luggage or having improper tire pressure.
●The distance to the preceding vehicle is extremely short.
●The vehicle is moving up and down a large amount due to road conditions during driv-ing (poor roads or road seams).
●The headlight lenses are dirty and emit a faint amount of light at night, or the beam axis has deviated.
●The vehicle is struck by a crosswind.
●The vehicle has just changed lanes or crossed an intersection.
●Snow tires, etc. are equipped.
■Warning message
Warning messages are used to indicate a syst em malfunction or to inform the driver of the need for caution while driving. ( P. 466)
■Customization
The following settings can be changed.
For how to change settings, refer to P. 561.
FunctionSetting details
Lane departure alert functionAdjust alert sensitivity
Adjust alert type
Steering assist functionTurn steering wheel assistance on and off
Vehicle sway warning functionTurn function on and off
Adjust alert sensitivity
Lane centering functionTurn function on and off

3294-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
■Automatic system cancelation of hill-start assist control
The hill-start assist control will be canc eled in any of the following situations;
●The shift lever is shifted to N or P.
●The accelerator pedal is depressed.
●The parking brake is engaged.
●Approximately 2 seconds elapse after the brake pedal is released.
■Operating conditions of emergency brake signal
When the following three conditions are me t, the emergency brake signal will operate:
●The emergency flashers are off.
●Actual vehicle speed is over 55 km/h (35 mph).
●The brake pedal is depressed in a manner that cause the system to judge from the vehi- cle deceleration that this is a sudden braking operation.
■Automatic system cancelation of emergency brake signal
The emergency brake signal will turn of f in any of the following situations:
●The emergency flashers are turned on.
●The brake pedal is released.
●The system judges from the vehicle deceleration that is not a sudden braking operation.
WARNING
■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
■TRC may not operate effectively when
Directional control and power may not be achievable while driving on slippery road surfaces, even if the TRC 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 the hill-start assist control. The hill-start assist control may not
operate effectively on steep inclines and roads covered with ice.
●Unlike the parking brake, hill-start assist co ntrol 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.

3304-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■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 TRC/VSC systems are turned off
Be especially careful and drive at a speed appropriate to the road conditions. As these are the systems to help ensure vehicle stability and driving force, do not turn the TRC/
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, TRC and VSC systems will not function correctly if different tires are installed
on the vehicle. Contact any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer 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 cause a system to malfunction.

3324-6. Driving tips
GS450h_300h_OM_OM30F92E_(EE)
◆Delays
Repeated acceleration and deceleration, as well as long waits at traffic lights,
will lead to bad fuel economy. Check traffic reports before leaving and avoid
delays as much as possible. When driving in a traffic jam, gently release the
brake pedal to allow the vehicle to move forward slightly while avoiding over-
use of the accelerator pedal. Doing so can help control excessive gasoline
consumption.
◆Highway driving
Control and maintain the vehicle at a constant speed. Before stopping at a toll
booth or similar, allow plenty of time to release the accelerator and gently
apply the brakes. A greater amount of electrical energy can be regenerated
when slowing down.
◆Air conditioning
Use the air conditioning only when necessary. Doing so can help reduce
excessive gasoline consumption.
In summer: When the ambient temperature is high, use the recirculated air
mode. Doing so will help to reduce the burden on the air conditioning system
and reduce fuel consumption as well.
In winter: Because the gasoline engine will not automatically cut out until it
and the interior of the vehicle are warm, it will consume fuel. Also, fuel con-
sumption can be improved by avoiding overuse of the heater.
◆Checking tire inflation pressure
Make sure to check the tire inflation pressure frequently. Improper tire infla-
tion pressure can cause poor fuel economy.
Also, as snow tires can cause large amounts of friction, their use on dry roads
can lead to poor fuel economy. Use ti res that are appropriate for the season.

3344-6. Driving tips
GS450h_300h_OM_OM30F92E_(EE)
Winter driving tips
●Use fluids that are appropriate to the prevailing outside temperatures.
•Engine oil
• Engine/power control unit coolant
•Washer fluid
●Have a service technician inspect the condition of the 12-volt 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 vehicles with front and rear tires of differing
sizes and vehicles with LDH and 19 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.
Carry out the necessary preparations an d 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

3364-6. Driving tips
GS450h_300h_OM_OM30F92E_(EE)
Vehicles with front and rear tires of the same size except for the vehicles with
LDH and 19 inch tires
Use the correct tire chain size when mounting the tire chains.
Chain size is regulated for each tire size.
Side chain
(3 mm [0.12 in.] in diameter)
Cross chain
(4 mm [0.16 in.] in diameter)
Vehicles with front and rear tires of differing sizes and vehicles with LDH and
19 inch tires
Tire chains cannot be mounted.
Snow tires should be used instead.
Regulations regarding the use of tire chai ns vary depending on location and type
of road. Always check local regulations before installing chains.
Selecting tire chains
1
2
Regulations on the use of tire chains

3374-6. Driving tips
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
If heavy snow or icy condition is expected, shift the rest position manually.
Grip the hook section of the wiper arm firmly when shifting the wiper position.
■To rest position
Raise the wiper in line with the wind-
shield.
You can stand the wipers up for the rest position.
★ : More than 10 cm (3.9 in.)
■To retract position
Lower the wipers by pressing on the
upper part of the hook section.
■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 0.5
 1.0 km (1/4  1/2 mile).
●Install tire chains following the instructions provided with the tire chains.
Shifting the windshield wiper position

3384-6. Driving tips
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Driving with snow tires
Observe the following precautions to reduce the risk of accidents. Failure to do so may result in a loss of vehicle control and cause death or serious injury.
●Use tires of the specified size.
●Maintain the recommended level of air pressure.
●Do not drive at speeds in excess of the speed limit or the speed limit specified for the
snow tires being used.
●Use snow tires on all, not just some wheels.
■Driving with tire chains (vehicles with front and rear tires of the same size except for
the vehicles with LDH and 19 inch tires)
Observe the following precautions to reduce the risk of accidents. Failure to do so may result in the vehicle being unable to be driven safely, and may
cause death or serious injury.
●Do not drive in excess of the speed limit sp ecified for the tire chains being used, or 50 km/h (30 mph), whichever is lower.
●Avoid driving on bumpy road surfaces or over potholes.
●Avoid sudden acceleration, abrupt steerin g, sudden braking and shifting operations that cause sudden engine braking.
●Slow down sufficiently before entering a curve to ensure that vehicle control is main-tained.
●Do not use LKA (Lane-Keeping Assist) system. (if equipped)
NOTICE
■Repairing or replacing snow tires
Request repairs or replacement of snow ti res from Lexus dealers or legitimate tire
retailers. This is because the removal and attachment of snow tires affects the operation of thetire pressure warning va lves and transmitters.
■Fitting tire chains (vehicles with front and rear tires of the same size except for the vehicles with LDH and 19 inch tires)
The tire pressure warning valves and transmitters may not function correctly when tire
chains are fitted.
■When standing the windshield wipers up
Raise the wipers in line with the windshield. ( P. 337)
Failure to do so may result in damage to the wipers and/or the hood.

389
6Maintenance and care
GS450h_300h_OM_OM30F92E_(EE)
6-1. Maintenance and care
Cleaning and protecting
the vehicle exterior ................390
Cleaning and protecting
the vehicle interior.................. 394
6-2. Maintenance
Maintenance
requirements ............................ 397
6-3. Do-it-yourself maintenance
Do-it-yourself service
precautions................................ 399
Hood ................................................ 401
Positioning a floor jack ............ 402
Engine compartment ...............403
12-volt battery ...............................412
Tires ...................................................416
Tire inflation pressure .............. 429
Wheels ............................................ 431
Air conditioning filter ............... 433
Electronic key battery.............. 435
Checking and replacing
fuses.............................................. 437
Light bulbs..................................... 442