2010 TOYOTA PRIUS Owners Manual

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2-4. Using other
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PRIUS_U (OM47668U) U.S.A.
CAUTION
■Situations unsuitable for the LKA system
Using the LKA system in any of the following situations may result in
improper operation of the system and could lead to an accident, causing
death or serious injury. Turn the LKA system off while driving in any of the
following situations.
● When it is difficult to see lane markings because they are dirty or not clear
● When it is difficult to see lane markings due to rain, snow, fog or glare
● When the headlights are not bright enough due to dirt on the lenses or if
the headlight aim is not adjusted appropriately
● When a lane marking is not present, such as before tollbooths on a free-
way
● When sudden changes in the light level occur repetitively
● When there are misleading lines such as shadows, lines of snow, wheel
ruts with rain collected in them, or lines that remain after road repairs
● When driving in lanes other than the driving lane or passing lane on free-
way or motor highways
● When there is a lane closure due to road repairs or when driving in a
makeshift lane
● When the lanes are narrow or wide
● When the distance from the vehicle ahead of you is short
● When the vehicle leans to one side an unusual amount due to a heavy
load or improper tire inflation pressure
● When driving on winding roads or on uneven roads
● When driving on slippery roads, such as those covered with rain, ice or \
snow
● The tires have been exchanged (including snow tires), or the suspension
has been modified

242 2-4. Using other driving systems
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NOTICE
■Camera sensor
● Keep the windshield clean at all times. 
LKA performance may deteriorate due to the presence of raindrops, con-
densation, ice or snow on the windshield.
● Do not subject the camera sensor to strong impact or force, and do not
disassemble the camera sensor.
● Do not change the installation position of the camera sensor or remove it.
The direction of the camera sensor is precisely adjusted.
● When it is cold, using the heater with air blowing to the feet may allow the
upper part of the windshield to fog up. This will have a negative effect on
the images. In such a case, use the windshield defogger to provide warm,
dry air to the windshield.
● Do not place anything on the dashboard. 
The camera sensor may recognize the image reflected on the windshield
as lane markings by mistake.
● Do not scratch the camera lens, or let it get dirty.
● Do not attach a sticker or other items to the windshield near the camera
sensor.
Observe the following to ensure that the
LKA system functions correctly.
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Hill-start assist control
■Hill-start assist control operating conditions
The system operates in the following situations:
• The shift position is in other than “P”.
• The parking brake is not applied.
• The accelerator pedal is not depressed.
■ Hill-start assist control
● While hill-start assist control is operating, the brakes remain automati-
cally applied after the driver releases the brake pedal. The stop lights and
the high mounted stoplight turn on.
● Hill-start assist control operates for about 2 seconds after the brake pedal
is released.
● If the slip indicator does not flash and the buzzer does not sound when
the brake pedal is further depressed, slightly reduce the pressure on the
brake pedal (do not allow the vehicl e to roll backward) and then firmly
depress it again. If the system still does not operate, check that the oper-
ating conditions explained above have been met.
Hill-start assist control helps to prevent the vehicle from rolling
backwards when starting on incline or slippery slope.
To engage hill-start assist con-
trol, further depress the brake
pedal when the vehicle is
stopped completely.
A buzzer will sound once to
indicate the system is acti-
vated. The slip indicator will
also start flashing.
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244 2-4. Using other driving systems
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■Hill-start assist control buzzer
● When hill-start assist control is activated, the buzzer will sound once.
● In the following situations, hill-start assist control will be canceled and the
buzzer will sound twice.
• No attempt is made to drive the vehicle within approximately 2 seconds
of releasing the brake pedal.
• The “P” position switch is pressed.
• The parking brake is applied.
• The brake pedal is depressed again.
■ If the slip indicator comes on...
It may indicate a malfunction in the system. Contact your Toyota dealer.
CAUTION
■Hill-start assist control
● Do not overly rely on hill-start assist control. Hill-start assist control may
not operate effectively on extremely st eep inclines or roads covered in ice.
● Unlike the parking brake, hill-start assist control is not intended to hold the
vehicle stationary for an extended period of time. Do not attempt to use
hill-start assist control to hold the vehicle on an incline for an extended
period of time, as doing so may lead to an accident.

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Driving assist systems
To help enhance driving safety and performance, the following sys-
tems operate automatically in res ponse to various driving situations.
Be aware, however, that these systems are supplementary and
should not be relied upon too h eavily when operating the vehicle.
■ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while driving on a slippery road surface.
■Brake assist
Generates an increased level of braking force after the brake pedal is
depressed, when the system detects a panic stop situation.
■Enhanced 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 front wheels from spinning
when starting the vehicle or accelerating on slippery roads.
■Hill-start assist control
P. 243
■ EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.
■Pre-Collision System (if equipped)
P. 249

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When the Enhanced VSC/TRAC is operatingIf the vehicle is in danger of slip-
ping or if the front wheels spin,
the slip indicator light flashes to
indicate that the Enhanced VSC/
TRAC have been engaged.
A buzzer (intermittent) sounds to
indicate that Enhanced VSC is
operating.
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■Sounds and vibrations caused by the ABS, brake assist, TRAC and
Enhanced VSC
● A sound may be heard from the engine compartment when the hybrid
system is started, just after the vehicle begins to move, if the brake pedal
is depressed forcefully or repeatedly, or 1 - 2 minutes after the hybrid
system is stopped. 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
operating. 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.
■ EPS operation sound
When the steering wheel operates, a mo tor sound (whirring sound) may be
heard. 
This does not indicate a malfunction.

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■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 hybrid system off.
The system should return to normal within 10 minutes.
CAUTION
■The ABS does not opera te effectively when
● The limits of tire gripping performance have been exceeded.
● The vehicle hydroplanes while driving at high speed on the wet or slick
road.
■ Stopping distance when the ABS is ope rating on the wet or slick roads
The ABS is not designed to shorten the vehicle’s stopping distance. Always
maintain a safe distance from the vehicle in front of you in the following situ-
ations.
● 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 roads with uneven pavement
■ TRAC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC is operating. 
Do not drive the vehicle in conditions where stability and power may be lost.

248 2-4. Using other driving systems
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CAUTION
■When the Enhanced VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive
carefully. 
Reckless driving may cause an accident. Exercise particular care when the
indicator light flashes and a buzzer sounds.
■ 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 speci-
fied tire pressure level.
The ABS and Enhanced VSC will not function correctly if different tires are
fitted on the vehicle.
Contact your Toyota 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 driving assist systems, and may cause the system to malfunction.