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4-5. Using the driving support systems
●When driving on rough or unpaved roads
● When driving on a sharp curve
● When lane markers are extremely narrow or extremely wide
● When the vehicle leans to one side an unusual amount due to a heavy load
or improper tire inflation pressure
● When the following distance between your vehicle and the vehicle ahead is
extremely short
● When the vehicle experiences strong up-and-down motion such as when
driving on an extremely rough road or on a seam in the pavement
● When headlight brightness at nighttime is reduced due to dirt on the lenses,
or when the headlights are misaligned
■ When changing the tires
Depending on the tires used, such as snow tires, etc., sufficient performance
may not be maintainable.
■ Warning messages for the LDA
Warning messages are used to indicate a system malfunction or to inform t\
he
driver of the need for caution while driving. If a warning message is sh\
own on
the multi-information display, read the message and follow the instructions.
Also, even if a warning message is displayed, it will not impede normal driv-
ing.

PRIUS v_OM_OM47B23U_(U)
2354-5. Using the driving support systems
4
Driving
WARNING
■Before using the LDA
Do not over rely on the LDA. The LDA does not drive the vehicle automati-
cally, nor does it reduce the amount of care you need to take. As such, the
driver must always assume full responsibility for understanding his/her sur-
roundings, for operating the steering wheel to correct the driving line, and
for driving safely. Also, take occasional rests from fatigue due to driving over
long periods of time, etc.
Inappropriate or negligent driving could lead to an unexpected accident.
■ To avoid operating the LDA by mistake
Switch the LDA off using the LDA switch when not in use. ( P. 230)
■ Situations unsuitable for LDA
Do not use the LDA in any of the following situations.
Otherwise, the system may not function correctly and could result in an
accident.
●When driving with tire chains, a spare tire, or similar equipment
● When there are objects or structures along the roadside that might be mis-
interpreted as lane markers (such as guardrails, a curb, reflector posts,
etc.)
● When driving on snowy roads
● When pavement lane markers are difficult to see due to rain, snow, fog,
sand, dirt, etc.
● When there are visible lines on the pavement from road repairs, or if the
remains of old lane markers are still visible on the road
● When driving through construction areas

PRIUS v_OM_OM47B23U_(U)
2454-5. Using the driving support systems
4
Driving
WARNING
■When using the rear view monitor system
The rear view monitor system is a supplemental device intended to assist
the driver when backing up. When backing up, be sure to visually check all
around the vehicle both directly and using the mirrors before proceeding.
Observe the following precautions to avoid an accident that could result in
death or serious injuries.
● Never depend on the rear view monitor system entirely when backing up.
The image and the position of the guide lines displayed on the screen may
differ from the actual state.
Use caution, just as you would when backing up any vehicle.
● Be sure to back up slowly, depressing the brake pedal to control vehicle
speed.
● The instructions given are only guide lines.
When and how much to turn the steering wheel will vary according to traf-
fic conditions, road surface conditions, vehicle condition, etc. when park-
ing. It is necessary to be fully aware of this before using the rear view
monitor system.
● When parking, be sure to check that the parking space will accommodate
your vehicle before maneuvering into it.
● Do not use the rear view monitor system in the following cases:
• On icy or slick road surfaces, or in snow
• When using tire chains or emergency tires
• When the back door is not closed completely
• On roads that are not flat or straight, such as curves or slopes
● In low temperatures, the screen may darken or the image may become
faint. The image could distort when the vehicle is moving, or you may
become unable to see the image on the screen. Be sure to visually check
all around the vehicle both directly and using the mirrors before proceed-
ing.
● If the tire sizes are changed, the position of the fixed guide lines displayed
on the screen may change.
● The camera uses a special lens. The distances between objects and
pedestrians that appear in the image displayed on the screen will differ
from the actual distances. ( P. 240)

PRIUS v_OM_OM47B23U_(U)
2514-5. Using the driving support systems
4
Driving
■Turning off both TRAC/VSC systems
To turn the TRAC/VSC systems off, press and hold for more than 3 sec-
onds while the vehicle is stopped.
Vehicles without multi-information display
The “TRAC OFF” and VSC OFF in dicator lights will come on.
Vehicles with multi-information display
The VSC OFF indicator light will come on and the message will be shown on
the multi-information display.
*
Press again to turn the systems back on.
*: On vehicles with pre-collision system, pre-collision brake assist and pre- collision braking will also be disabled. The PCS warning light will come on
and the message will be shown on the multi-information display. ( P. 493)
■ When the “TRAC OFF” indicator co mes on/message is displayed on the
multi-information display showing that TRAC has been disabled even if
the VSC OFF switch has not been pressed
TRAC cannot be operated. Contact your Toyota dealer.
■ Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and
hill-start assist control systems
Any of the following conditions may occur when the above systems are oper-
ating. 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.
■ ECB operating sound
ECB operating sound may be heard in the following cases, but it does not
indicate that a malfunction has occurred.
●Operating sound heard from the engine compartment when the brake pedal
is operated.
● Motor sound of the brake system heard from the front part of the vehicle
when the driver’s door is opened.
● Operating sound heard from the engine compartment when 1 or 2 minutes
passed after the stop of the hybrid system.
■ EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be
heard. This does not indicate a malfunction.

252
PRIUS v_OM_OM47B23U_(U)
4-5. Using the driving support systems
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system 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 EPS system should return to normal within 10 minutes.
■ Automatic reactivation of TRAC system
After turning the TRAC system off, the system will be automatically re-
enabled in the following situations:
●When the power switch is turned off
● The TRAC will turn on when vehicle speed increases
■ Electric power steering system warning light (warning buzzer)
P. 493
■ Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will
operate:
●The shift position is in a position other than P or N (when starting off forward/
backward on an upward incline).
● The vehicle is stopped.
● The accelerator pedal is not depressed.
● The parking brake is not engaged.
■ Automatic system cancelation of hill-start assist control
The hill-start assist control will turn off in any of the following situations:
● Shift the shift position to P or N.
● The accelerator pedal is depressed.
● The parking brake is engaged.
● Approximately 2 seconds elapse after the brake pedal is released.

PRIUS v_OM_OM47B23U_(U)
2534-5. Using the driving support systems
4
Driving
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 road.
■ Stopping distance when the ABS is operating may exceed that of nor-
mal 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
■ TRAC may not operat e effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC 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 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, as doing so may
lead to an accident.
■ 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 TRAC/VSC syst em is turned off
Be especially careful and drive at a speed appropriate to the road condi-
tions. As this is the system to help ensure vehicle stability and driving force,
do not turn the TRAC/VSC system off unless necessary.

254
PRIUS v_OM_OM47B23U_(U)
4-5. Using the driving support systems
WARNING
■Replacing tires
Make sure that all tires are of the specified size and of the same brand,
tread pattern and total load capacity. In addition, make sure that the tires are
inflated to the recommended tire inflation pressure level.
The ABS, VSC and TRAC systems will not function correctly if different tires
are installed on the vehicle.
Contact your Toyota dealer for further information when replacing tires or
wheels.
■ Handling of tires and the suspension
Using tires with any kind of problem or modifying the suspension will affect
the driving assist systems, and may cause a system to malfunction.

255
PRIUS v_OM_OM47B23U_(U)
4-5. Using the driving support systems
4
Driving
PCS (Pre-Collision System)
◆Pre-collision warning
When a high possibility of a frontal
collision is detected, a buzzer
sounds and a message is shown
on the multi-information display to
urge the driver to take evasive
action.
◆Pre-collision brake assist
When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to how strongly the brake pedal is
depressed.
◆Pre-collision braking
When there is a high possibility of a frontal collision, the system warns the
driver using a warning display and buzzer. If the system determines that a
collision is unavoidable, the brakes are automatically applied to reduce the
collision speed.
: If equipped
When the radar sensor detects pos sibility of a frontal collision,
brakes are automatically engaged to lessen impact as well as
vehicle damage.
The alert timing for the pre-co llision system can be changed or
turned ON/OFF, as necessary, by operating the switch. ( P. 256)