
2564-5. Using the driving support systems
IS300h_EE(OM53B95E)
Dynamic radar cruise control can be set when
The shift lever is in D or range 4 or higher of S has been selected.
Range 4 or higher of D has been selected by using the paddle shift.
Vehicle speed is above approximately 50 km/h (30 mph).
Accelerating after setting the vehicle speed
The vehicle can accelerate normally. After acceleration, the set speed resumes.
However, during vehicle-to-vehicle distance control mode, the vehicle speed
may decrease below the set speed in order to maintain the distance to the vehicle
ahead.
Automatic cancelation of vehicle-to-vehicle distance control
Vehicle-to-vehicle distance control driving is automatically canceled in the fol-
lowing situations:
Actual vehicle speed falls below approximately 40 km/h (25 mph).
VSC is activated.
TRC is activated for a period of time.
When the VSC or TRC system is turned off by pressing the VSC OFF switch.
The sensor cannot operate correctly because it is covered in some way.
The windshield wipers are operating at high speed (when the wipers are in
AUTO mode or the high speed wiper operation).
When snow mode is set.
Pre-crash braking is activated.
If vehicle-to-vehicle distance control driving is automatically canceled for any
other reason, there may be a malfunction in the system. Contact any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional.
Automatic cancelation of constant speed control
The cruise control will stop maintaining the vehicle speed in the following situa-
tions:
Actual vehicle speed is more than approximately 16 km/h (10 mph) below the
set vehicle speed.
At this time, the memorized set speed is not retained.
Vehicle speed falls below approximately 40 km/h (25 mph).
VSC is activated.
TRC is activated for a period of time.
When the VSC or TRC system is turned off by pressing the VSC OFF switch.
Pre-crash braking is activated.

2574-5. Using the driving support systems
4
Driving
IS300h_EE(OM53B95E)
Radar sensor and grille cover
Always keep the sensor and grille cover clean to ensure that the vehicle-to-vehi-
cle distance control operates properly. (Some obstructions, such as snow, ice and
plastic objects, cannot be detected by the obstruction sensor.)
Dynamic radar cruise control is canceled if an obstruction is detected.
Operation guide display
When the dynamic radar cruise control switch is operated, a guidance display is
shown on the meters for a few seconds as to how to operate the dynamic radar
cruise control switch or distance switch. (P. 1 1 9 )
Warning messages and buzzers for dynamic radar cruise control
Warning messages and buzzers are used to indicate a system malfunction or to
inform the driver of the need for caution while driving. (P. 518) Grille cover
Radar sensor
1
2

2624-5. Using the driving support systems
IS300h_EE(OM53B95E)
Before using dynamic radar cruise control
Do not overly rely on vehicle-to-vehicle distance control.
Be aware of the set speed. If automatic deceleration/acceleration is not appro-
priate, adjust the vehicle speed, as well as the distance between your vehicle
and vehicles ahead by applying the brakes etc.
Cautions regarding the driving assist systems
Observe the following precautions.
Failure to do so may cause an accident resulting in death or serious injury.
Assisting the driver to measure following distance
The dynamic radar cruise control is only intended to help the driver in deter-
mining the following distance between the driver’s own vehicle and a desig-
nated vehicle traveling ahead. It is not a mechanism that allows careless or
inattentive driving, and it is not a system that can assist the driver in low-visi-
bility conditions. It is still necessary for driver to pay close attention to the
vehicle’s surroundings.
Assisting the driver to judge proper following distance
The dynamic radar cruise control determines whether the following distance
between the driver’s own vehicle and a designated vehicle traveling ahead is
appropriate or not. It is not capable of making any other type of judgement.
Therefore, it is absolutely necessary for the driver to remain vigilant and to
determine whether or not there is a possibility of danger in any given situa-
tion.
Assisting the driver to operate the vehicle
The dynamic radar cruise control has no capability to prevent or avoid a colli-
sion with a vehicle traveling ahead. Therefore, if there is ever any danger, the
driver must take immediate and direct control of the vehicle and act appropri-
ately in order to ensure the safety of all involved.
To avoid inadvertent cruise control activation
Switch the cruise control off using the “ON/OFF” button when not in use.
Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise control in any of the following situations.
Doing so may result in inappropriate speed control and could cause an accident
resulting in death or serious injury.
In heavy traffic
On roads with sharp bends
On winding roads
On slippery roads, such as those covered with rain, ice or snow
On steep downhills, or where there are sudden changes between sharp up and
down gradients
Vehicle speed may exceed the set speed when driving down a steep hill.
At entrances to expressways
When weather conditions are bad enough that they may prevent the sensors
from functioning correctly (fog, snow, sandstorm, heavy rain, etc.)
When an approach warning buzzer is heard often
When your vehicle is towing a trailer or during emergency towing

2634-5. Using the driving support systems
4
Driving
IS300h_EE(OM53B95E)
CAUTION
When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are
in front of you.
As the sensor may not be able to correctly detect these types of vehicles, the
approach warning (P. 254) will not be activated, and a fatal or serious acci-
dent may result.
Vehicles that cut in suddenly
Vehicles traveling at low speeds
Vehicles that are not moving
Vehicles with small rear ends (trailers with no load on board etc.)
Motorcycles traveling in the same lane
Conditions under which the vehicle-to-vehicle distance control may not func-
tion correctly
Apply the brakes as necessary in the following conditions as the radar sensor
may not be able to correctly detect vehicles ahead, and a fatal or serious acci-
dent may result:
When water or snow thrown up by a the surrounding vehicles hinders the
functioning of the sensor
When your vehicle is pointing upwards (caused by a heavy load in the trunk
etc.)
When the road curves or when the lanes are narrow
When steering wheel operation or your position in the lane is unstable
When the vehicle ahead of you decelerates suddenly
Handling the radar sensor
Observe the following to ensure the cruise control system can function effec-
tively.
Otherwise, the system may not function correctly and could result in an acci-
dent.
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 dam-
age them.
Do not subject the sensor or surrounding area to a strong impact.
If the sensor moves even slightly off position, the system may malfunction. If
the sensor or surrounding area is subject to a strong impact, always have the
area inspected and adjusted by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
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.

5198-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53B95E)
(If equipped)
Indicates that the dynamic radar cruise control sys-
tem is unable to judge vehicle-to-vehicle distance
A buzzer also sounds.
Turn off snow mode.
If the windshield wipers are on, turn them off or
set them to a mode other than AUTO or high
speed wiper operation.
(If equipped)
Indicates that the LDA (Lane Departure Alert) sys-
tem is suspended
The camera sensor temperature is higher than the
operation temperature range.
A buzzer also sounds.
Restart the LDA after driving for a while.
(If equipped)
Indicates that:
• The grille shutter system cannot operate; or
• The grille shutter is dirty or covered with ice
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
(If equipped)
Indicates that a Blind Spot Monitor sensor or the
surrounding area on the bumper is dirty or covered
with ice
A buzzer also sounds.
Clean the sensor and its surrounding area on the
bumper.
(If equipped)
Indicates a malfunction in:
• The cruise control system; or
• The dynamic radar cruise control system
Press the “ON/OFF” button once to deactivate the
system, and then press the button again to reacti-
vate the system.
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
(If equipped)
Indicates a malfunction in the LDA (Lane Depar-
ture Alert) system
A buzzer also sounds.
Have the vehicle inspected by any authorized
Lexus dealer or repairer, or another duly quali-
fied and equipped professional.
Warning messageDetails/Actions

5258-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53B95E)
Warning messages
The warning message illustrations used are intended as examples, and may differ
from the image that is actually displayed on the multi-information display.
Warning message in radar cruise mode (if equipped)
In the following situations, the warning message 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
The LDA (Lane Departure Alert) lane departure warning function (if equipped)
In the following situations, the warning message will not be displayed even if a
lane line is crossed.
When the vehicle speed deviates from the operating range of the LDA system
functions
When the lane lines cannot be recognized
After changing the engine oil (if equipped)
Make sure to reset the oil change system. (P. 442)
Warning buzzer
P. 512

595Alphabetical index
IS300h_EE(OM53B95E)
Clock .........................................420
Coat hooks .................................424
Condenser .................................446
Console box ...............................414
Coolant ......................................444
Capacity ................................567
Checking ...............................444
Preparing and checking
before winter ......................311
Cooling system ..........................444
Engine overheating ...............556
Hybrid system overheating ...556
Cruise control
Cruise control .......................245
Dynamic radar cruise control .....
249
Cup holders ...............................415
Current fuel consumption ..........117
Curtain shield airbags .................43
Customizable features ...............576DAB (Digital Audio Broadcast)339
Daytime running light system . 227
Defogger
Front windshield .................. 404
Outside rear view mirrors .... 404
Rear window ........................ 404
Differential ............................... 569
Digital Audio Broadcast (DAB)339
Dimensions ............................... 562
Display
Drive information ................ 117
Dynamic radar cruise control ....
249
LDA (Lane Departure Alert) 265
Multi-information display.... 116
Warning message................. 514
Distance .................................... 118
Do-it-yourself maintenance ...... 435
Door courtesy lights
Location ............................... 411
Wattage ................................ 572
Door lock
Doors ................................... 136
Smart entry & start system .. 149
Wireless remote control ....... 130D

596Alphabetical index
IS300h_EE(OM53B95E)
Doors .........................................136
Automatic door locking and
unlocking system................140
Door glasses .........................184
Door lock ..............................139
Open door warning buzzer ...137
Open door warning
light ....................................509
Outside rear view mirrors .....180
Rear door child-protector ....140
Drive information ......................117
Drive info 1/Drive info 2...........118
Driver’s and front passenger’s
seat belt reminder light ...........509
Driver’s seat position memory ..168
Driving ......................................192
Break-in tips .........................193
Correct driving posture ...........36
Driving mode select switch ..290
Hybrid vehicle driving tips ...309
Procedures ............................192
Winter drive tips ...................311
Dynamic radar cruise control ....249E-mail ....................................... 375
Eco drive mode......................... 290
Elapsed time ............................. 117
Electric motor (traction motor)... 79
Electric Power Steering (EPS) . 293
Function ............................... 293
Warning light ....................... 508
Electronic key ........................... 130
Battery-saving function ....... 150
If the electronic key does not
operate properly ................ 549
Replacing the battery ........... 472
Emergency, in case of
If the 12-volt battery is
discharged ......................... 551
If the electronic key does not
operate properly ................ 549
If the hybrid system will not
start .................................... 546
If the shift lever cannot be
shifted from P .................... 548
If the warning buzzer sounds507
If the warning light turns on 507
If the warning message is
displayed ........................... 514E