2010 Lexus GS450h brakes

141
2-1. Driving procedures
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
■Driving in the rain
●Drive carefully when it is raining, because visibility will be reduced, the windows
may become fogged-up, and the road will be slippery.
●Drive carefully when it starts to rain, because the road surface will be especially
slippery.
●Refrain from high speeds when driving on an expressway in the rain, because
there may be a layer of water between the tires and the road surface, preventing
the steering and brakes from operating properly.
■Breaking in your new Lexus
To extend the life of the vehicle, the following precautions are recommended to
observe:
●For the first 186 miles (300 km):
Avoid sudden stops.
●For the first 621 miles (1000 km):
• Do not drive at extremely high speeds.
• Avoid sudden acceleration.
• Do not drive continuously in the low range in the “S” position.
• Do not drive at a constant speed for extended periods.
■Drum-in-disc type parking brake system
Your vehicle has a drum-in-disc type parking brake system.
This type of brake system needs bedding-down of the brake shoes periodically or
whenever the parking brake shoes and/or drums are replaced.
Have your Lexus dealer perform the bedding-down.
■Operating your vehicle in a foreign country
Comply with the relevant vehicle registration laws and confirm the availability of the
correct fuel. (P. 5 9 0 )
■When starting on an incline
The hill-start assist control may operate. (P. 2 1 4 )

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2-1. Driving procedures
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■When driving the vehicle
●Moving the shift lever to "N" while the vehicle is moving will disengage the hybrid
system. Engine braking is not available with the hybrid system disengaged.
●During normal driving, do not turn off the hybrid system. Turning the hybrid sys-
tem off while driving will not cause loss of steering or braking control, but the
power assist to these systems will be lost. This will make it more difficult to steer
and brake, so you should pull over and stop the vehicle as soon as it is safe to do
so.
However, in the event of an emergency, such as if it becomes impossible to stop
the vehicle in the normal way: P. 5 3 4
●Use engine braking (downshift) to maintain a safe speed when driving down a
steep hill. 
Using the brakes continuously may cause the brakes to overheat and lose effec-
tiveness. (P. 1 5 6 )
●When stopped on an inclined surface, use the brake pedal and parking brake to
prevent the vehicle from rolling backward or forward and causing an accident.
●Be careful when driving on slippery surfaces, as the vehicle may spin or skid when
downshifting, rapidly accelerating, braking or turning.
●Do not adjust the position of the steering wheel, the seat, or the inside or outside
rear view mirrors while driving.
Doing so may result in a loss of vehicle control that can cause accidents that may
result in death or serious injury.
●Always check that all passengers’ arms, heads or other parts of their bodies are
not outside the vehicle, as this may result in death or serious injury.
●Do not drive in excess of the speed limit. Even if the legal speed limit permits it, do
not drive over 85 mph (140 km/h) unless your vehicle has high-speed capability
tires. Driving over 85 mph (140 km/h) may result in tire failure, loss of control and
possible injury. Be sure to consult a tire dealer to determine whether the tires on
your vehicle are high-speed capability tires or not before driving at such speeds.
●The driver should pay attention to pedestrians when the vehicle is powered only
by the electric motor (traction motor). Because there is no engine sounds, the
pedestrians may misjudge the vehicle’s movement.

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2-1. Driving procedures
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■When driving on slippery road surfaces
●Sudden braking, acceleration and steering may cause tire slippage and reduce
your ability to control the vehicle, resulting in an accident.
●Sudden changes in engine speed, such as engine braking caused by up-shifting
or down-shifting, may cause the vehicle to skid, resulting in an accident.
●After driving through a puddle, lightly depress the brake pedal to make sure that
the brakes are functioning properly. Wet brake pads may prevent the brakes from
functioning properly. If the brakes on only one side are wet and not functioning
properly, steering control may be affected, resulting in an accident.
■When shifting the shift lever
Be careful not to shift the shift lever with the accelerator pedal depressed.
This may lead to unexpected rapid acceleration of the vehicle that may cause an
accident and result in death or serious injury.
■When the vehicle is stopped
●Do not race the hybrid system.
If the vehicle is in any positions other than “P” or “N” the vehicle may accelerate
suddenly and unexpectedly, and may cause an accident.
●Do not leave the vehicle with the hybrid system on for a long time.
If such a situation cannot be avoided, park the vehicle in an open space and
check that exhaust fumes do not enter the vehicle interior.
●In order to prevent accidents due to the vehicle rolling away, always keep
depressing the brake pedal while the “READY” indicator is on. Apply the parking
brake as necessary.
●If the vehicle is stopped on an incline, in order to prevent accidents caused by the
vehicle rolling forward or backward, always depress the brake pedal and securely
apply the parking brake as needed.
●Avoid revving or racing the engine. Running the engine at high speed while the
vehicle is stopped may cause the exhaust system to overheat, which could result
in a fire if combustible material is nearby.

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2-1. Driving procedures
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■When taking a nap in the vehicle
Always turn the hybrid system off. Otherwise, you may accidentally move the shift
lever or depress the accelerator pedal, which could cause an accident or fire due to
hybrid system overheating. Additionally, if the vehicle is parked in a poorly venti-
lated area, exhaust gases may collect and enter the vehicle, leading to death or a
serious health hazard.
■When braking the vehicle
●When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and may cause one side of
the vehicle to brake differently than the other side. Also the parking brake may
not securely hold the vehicle.
●If the brake actuator does not operate, do not follow other vehicles closely and
avoid downhill or sharp turns that require making. 
In this case, braking is still possible, but it will require more force on the pedal than
usual. Braking distance may also increase.
●The brake system consists of 3 individual hydraulic systems: If one of the systems
fails, the other will still operate. In this case, the brake pedal should be depressed
more firmly than usual and braking distance becomes longer.
Do not drive your vehicle with only a single brake system. Have your brakes fixed
immediately.
■If the vehicle becomes stuck or bogged
Do not spin the wheels recklessly when any of the tires is up in the air, or stuck in
sand or mud, etc. This may damage the drive system components or propel the
vehicle forward (or in another direction) and cause an accident.

187
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
■Changing the vehicle-to-vehicle distance
Pulling the lever toward you
changes the vehicle-to-vehicle
distance as follows:
Long
Medium
Short
The vehicle-to-vehicle distance
is set automatically to long
mode when the “POWER”
switch is turned to ON mode.
If a vehicle is running ahead of
you, the preceding vehicle mark
will also be displayed.
■Canceling and resuming the speed control
Pulling the lever toward you
cancels the cruise control.
The speed setting is also can-
celed when the brakes are
applied.
Pushing the lever up resumes
the cruise control and returns
vehicle speed to the set
speed.
Resuming is available when the
vehicle speed is more than
approximately 25 mph (40 km/
h).
Preceding
vehicle mark

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2-4. Using other driving systems
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
Example of constant speed cruising 
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-vehi-
cle distance can also be set by operating the vehicle-to-vehicle distance con-
trol.
Example of deceleration cruising 
When the vehicle ahead is driving slower than the set speed
When a vehicle is detected running ahead of you, the system automatically
decelerates your vehicle. When a greater reduction in vehicle speed is nec-
essary, the system applies the brakes. A warning tone warns you when the
system cannot decelerate sufficiently to prevent your vehicle from closing in
on the vehicle ahead.
Example of follow-up cruising 
When following a vehicle driving slower than the set speed
The system continues follow-up cruising while adjusting for changes in the
speed of the vehicle ahead in order to maintain the vehicle-to-vehicle dis-
tance set by the driver.
Example of acceleration 
When there are no longer any vehicles ahead driving slower than the
set speed
The system accelerates until the set speed is reached. The system then
returns to constant speed cruising.
Approach warning
When your vehicle is too close to a vehicle ahead, and sufficient auto-
matic deceleration via the cruise control is not possible, the display will
flash and the buzzer will sound to alert the driver. An example of this
would be if another driver cuts in front of you while you are following a
vehicle. Apply the brakes to ensure an appropriate vehicle-to-vehicle dis-
tance.

194
2-4. Using other driving systems
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■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 appropri-
ate, adjust the vehicle speed, as well as the distance between your vehicle and vehi-
cles 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 determin-
ing the following distance between the driver’s own vehicle and a designated
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-visibility 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 deter-
mine whether or not there is a possibility of danger in any given situation.
●Assisting the driver to operate the vehicle
The dynamic radar cruise control has no capability to prevent or avoid a collision 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 appropriately in order to ensure
the safety of all involved.
■To avoid operating the dynamic radar cruise control by mistake
Switch the cruise control off using the “ON-OFF” button when not in use.

195
2-4. Using other driving systems
2
When driving
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■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 and 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
●During emergency towing
■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. 551) will not be activated, and a fatal or serious accident
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