
302
PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
■Object detection function
■ Cancelation of the pre-collision braking
If either of the following occur while the pre-collision brakin g function is oper-
ating, it will be canceled:
● The accelerator pedal is depressed strongly.
● The steering wheel is turned sharply or abruptly.
■ Conditions under which the system may operate even if there is  no pos-
sibility of a collision
● In  some  situations  such  as  the  following,  the  system  may  determ ine  that
there is a possibility of a frontal collision and operate.
• When passing a detectable object, etc.
• When changing lanes while overtaking a detectable object, etc.
• When rapidly closing on a detectable object, etc.
• When  approaching  objects  on  the  roadside,  such  as  detectable  o bjects,
guardrails, utility poles, trees, or walls
The  system  detects  objects  based  on
their  size,  profile,  motion,  etc.  However,
an object may not be detected depending
on  the  surrounding  brightness  and  the
motion,  posture,  and  angle  of  the
detected  object,  preventing  the  system
from operating properly. (
P. 304) 
The illustration shows an image of detect-
able objects.
• When  approaching  a  detectableobject  in  an  adjacent  lane  or  on  the
roadside, such as when changing the
course  of  travel  or  driving  on  a  wind-
ing road 

PRIUS_OM_OM47E09U_(U)
3054-5. Using the driving support systems
4
Driving
• If a vehicle ahead is narrow, such as a personal mobility vehi cle
• If a preceding vehicle has a small rear end, such as an unload ed truck
• If a vehicle ahead is carrying a load which protrudes past its rear bumper
• If a vehicle ahead is irregularly shaped, such as a tractor or side car
• If a vehicle ahead is a child sized bicycle, a bicycle that is  carrying a large
load,  a  bicycle  ridden  by  more  than  one  person,  or  a  uniquely  shaped
bicycle (bicycle with a child seat, tandem bicycle, etc.)
• If  a  pedestrian/or  the  riding  height  of  a  bicyclist  ahead  is  s horter  than
approximately 3.2 ft. (1 m) or taller than approximately 6.5 ft. (2 m)
• If  a  pedestrian/bicyclist  is  wearing  oversized  clothing  (a  rai n  coat,  long
skirt, etc.), making their silhouette obscure
• If a pedestrian is bending forward or squatting or bicyclist i s bending for-
ward
• If a pedestrian/bicyclist is moving fast
• If a pedestrian is pushing a stroller, wheelchair, bicycle or  other vehicle
• When  driving  in  inclement  weather  such  as  heavy  rain,  fog,  snow  or  a
sandstorm
• When driving through steam or smoke
• When  the  surrounding  area  is  dim,  such  as  at  dawn  or  dusk,  or  while  at
night  or  in  a  tunnel,  making  a  detectable  object  appear  to  be  n early  the
same color as its surroundings
• When driving in  a place where the  surrounding brightness changes  sud-
denly, such as at the entrance or exit of a tunnel
• After the hybrid system has started the vehicle has not been d riven for a
certain amount of time
• While  making  a  left/right  turn  and  for  a  few  seconds  after  mak ing  a  left/
right turn
• While driving on a curve and for a few seconds after driving o n a curve
• If your vehicle is skidding • If  a  preceding  vehicle  has  a  low  rear end, such as a low bed trailer
• If a vehicle ahead has extremely high ground clearance 

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
WARNING
■When the TRAC/VSC systems are turned off
Be  especially  careful  and  drive  at  a  speed  appropriate  to  the  r oad  condi-
tions. As  these  are  the  systems  to  help  ensure  vehicle  stabilit y  and  driving
force, do not turn the TRAC/VSC systems off unless necessary.
■ Replacing tires
Make  sure  that  all  tires  are  of  the  specified  size,  brand,  trea d  pattern  and
total  load  capacity.  In  addition,  make  sure  that  the  tires  are  inflated  to  the
recommended tire inflation pressure level.
The ABS, TRAC and VSC systems will not function correctly if di fferent tires
are installed on the vehicle.
Contact  your  Toyota  dealer  for  further  information  when  replaci ng  tires  or
wheels.
■ Handling of tires and the suspension
Using tires with any kind of problem or modifying the suspensio n will affect
the driving assist systems, and may cause a system to malfuncti on. 

PRIUS_OM_OM47E09U_(U)
4314-6. Driving tips
4
Driving
Accelerate the vehicle slowly, keep a safe distance between you and
the vehicle ahead, and drive at a reduced speed suitable to roa d con-
ditions.
Park  the  vehicle  and  shift  the  shift  position  to  P  and  block  th e  wheel
under the vehicle without setting the parking brake. The parkin g brake
may  freeze  up,  preventing  it  fro m  being  released.  If  the  vehicle  is
parked  without  setting  the  parking  brake,  make  sure  to  block  th e
wheels.
Failure to do so may be dangerous because it may cause the vehi cle
to move unexpectedly, possi bly leading to an accident.
Use  the  correct  tire  chain  size   when  mounting  the  tire  chains.  Chain
size is regulated for each tire size.
Side chain
0.12 in. (3.0 mm)
1.18 in. (30.0 mm)
0.39 in. (10.0 mm)
Cross chain 0.16 in. (4.0 mm)
0.98 in. (25.0 mm)
0.55 in. (14.0 mm)
Regulations  regarding  the  use  of  tire  chains  vary  depending  on  loca-
tion and type of road. Always chec k local regulations before installing
chains. 
When driving the vehicle
When parking the vehicle
Selecting tire chains
1
2
3
4
5
6
Regulations on the use of tire chains 

432
PRIUS_OM_OM47E09U_(U)
4-6. Driving tips
■Tire chain installation
Observe the following precautions when installing and removing  chains:
● Install and remove tire chains in a safe location. 
● Install tire chains on the front tires only. Do not install tir e chains on the rear
tires.
● Install tire chains on front tires as tightly as possible. Reti ghten chains after
driving 1/4 - 1/2 mile (0.5 - 1.0 km).
● Install tire chains following the instructions provided with th e tire chains. 
WARNING
■Driving with snow tires
Observe the following precautions to reduce the risk of acciden ts. 
Failure  to  do  so  may  result  in  a  loss  of  vehicle  control  and  ca use  death  or
serious injury.
● Use tires of the specified size.
● Maintain the recommended level of air pressure.
● Do  not  drive  in  excess  of  75  mph  (120  km/h),  regardless  of  the  type  of
snow tires being used.
● Use snow tires on all, not just some wheels.
■ Driving with tire chains
Observe the following precautions to reduce the risk of acciden ts. 
Failure  to  do  so  may  result  in  the  vehicle  being  unable  to  be  d riven  safely,
and may cause death or serious injury.
● Do not drive in excess of the speed limit specified for the tir e chains being
used, or 30 mph (50 km/h), whichever is lower.
● Avoid driving on bumpy road surfaces or over potholes.
● Avoid  sudden  acceleration,  abrupt  steering,  sudden  braking  and  shifting
operations that cause sudden engine braking.
● Slow down sufficiently before entering a curve to ensure that v ehicle con-
trol is maintained.
● Do not use LTA (Lane Tracing Assist) (if equipped).
■ When parking the vehicle
When parking the vehicle without applying the parking brake, ma ke sure to
chock  the  wheels.  If  you  do  not  chock  the  wheels,  the  vehicle  m ay  move
unexpectedly, possibly resulting in an accident. 

536
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
■When to replace your vehicle’s tires
Tires should be replaced if:
●The treadwear indicators are showing on a tire.
●You  have  tire  damage  such  as  cuts,  splits,  cracks  deep  enough  t o
expose the fabric, and bulges  indicating internal damage.
●A tire goes flat repeatedly or c annot be properly repaired due  to the size
or location of a cut or other damage.
If you are not sure, consult  with your Toyota dealer.
■Replacing tires and wheels
If the ID code of the tire press ure warning valve and transmitt er is not reg-
istered, the tire pressure warni ng system will not work properly.  A f t e r   d r i v -
ing  for  about  20  minutes,  the  tire  pressure  warning  light  blink s  for  1
minute and stays on to indi cate a system malfunction.
■Tire life
Any tire over 6 years old must  be checked by a qualified techni cian even
if it has seldom or never been u sed or damage is not obvious.
■Routine tire inflation pressure checks
The  tire  pressure  warning  system  does  not  replace  routine  tire  inflation
pressure  checks.  Make  sure  to  chec k  tire  inflation  pressure  as part  of
your routine of daily vehicle checks.
■Maximum load of tire
Check that the maximum load of t he replacement tire is greater than 1/2
of  the  Gross Axle  Weight  Ratings  (GAWR)  of  either  the  front  axl e  or  the
rear axle, whichever is greater.
For  the  GAWR,  see  the  Certification
Label. For the maximum load of the tire,
see  the  load  limit  at  maximum  cold  tire
inflation  pressure  mentioned  on  the
sidewall of the tire. ( P.   6 7 8 )
BTO62EP049 

538
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
■Situations  in  which  the  tire  pressure  warning  system  may  not  oper-
ate properly
●In the following cases, the tire pressure warning system may no t operate
properly.
• If non-genuine Toyota wheels are used.
• When  a  replacement  tire  is  used,   the  system  may  not  operate  cor-
rectly due to the structure  of the replacement tire.
• A tire has been replac ed with a tire that is not of the specif ied size.
• Tire chains etc . are equipped.
• An auxiliary-supported ru n-flat tire is equipped.
• If a window tint that affects the radio wave signals is instal led.
• If  there  is  a  lot  of  snow  or  ice  on  the  vehicle,  particularly  around  the
wheels or wheel housings.
• If  the  tire  inflation  pressure  is  extremely  higher  than  the  sp ecified
level.
• If  wheel  without  the  tire  pressure  warning  valve  and  transmitt er  is
used.
• If the ID code on the tire pressure warning valves and transmi tters is
not registered in the tire  pressure warning computer.
●Performance may be affected in the following situations.
• Near a TV tower, electric power plant, gas station, radio stat ion, large
display,  airport  or  other  facilit y  that  generates  strong  radio  waves  or
electrical noise
• When  carrying  a  portable  radio,  cellular  phone,  cordless  phone  or
other wireless communication device
●When the vehicle is parked, the time taken for the warning to s tart or go
off could be extended.
●When tire inflation pressure declines rapidly for example when  a tire has
burst, the warning may not function.
■The initialization operation
●Make sure to carry out initializ ation after adjusting the tire inflation pres-
sure.
Also, make sure the tires are co ld before carrying out initialization or tire
inflation pressure adjustment.
●If you have accidentally turned the power switch off during ini tialization,
it  is  not  necessary  to  press  the  reset  swit ch  again  as  initialization  will
restart  automatically  when  the  power  switch  has  been  turned  to  ON
mode for the next time.
●If you accidentally press the reset switch when initialization  is not neces-
sary,  adjust  the  tire  inflation  pressure  to  the  specified  level   when  the
tires are cold, and cond uct initialization again. 

545
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
6
Maintenance and care
Wheels
When replacing wheels, care should be taken to ensure that they are
equivalent to those removed in load capacity, diameter, rim wid th and
inset
*.
Replacement wheels are available at your Toyota dealer.
*: Conventionally referred to as “offset”.
Toyota does not recommend using the following:
● Wheels of different sizes or types
● Used wheels
● Bent wheels that hav e been straightened
● Use  only  Toyota  wheel  nuts  and  wrenches  designed  for  use  with
your aluminum wheels.
● When  rotating,  repairing  or  changi ng  your  tires,  check  that  the
wheel nuts are still tight afte r driving 1000 miles (1600 km).
● Be  careful  not  to  damage  the  aluminum  wheels  when  using  tire
chains.
● Use only Toyota genuine balance we ights or equivalent and a plas-
tic or rubber hammer when balancing your wheels.
If  a  wheel  is  bent,  cracked  or  heavily  corroded,  it  should  be
replaced.  Otherwise,  the  tire  may  separate  from  the  wheel  or
cause a loss of handling control.
Wheel selection
Aluminum wheel precautions