Toyota Prius Prime (2020 year). Owner's manual - part 31

488

5-5. Using the driving support systems

WARNING

●

Observe  the  following  precautions,  as  the  sensors  may  stop  functioning
properly which may lead to an accident.
• Do not subject the sensor to strong shocks by hitting it, etc. The sen-

sors may not function properly.

• When using a high-pressure washer to wash the vehicle, do not spray

water  directly  on  the  sensors.  Equipment  may  not  function  properly  if
subjected  to  an  impact  from  strong  water  pressure.  If  the  vehicle
bumper strikes something, equipment may not operate properly due to
a sensor malfunction. Have the vehicle inspected at your Toyota dealer.

●

In the following situations, the sensors may not operate normally and may
lead to an accident. Drive carefully.
• Obstacles cannot be detected in the side areas until a scan of the side

areas is completed. (

P. 438)

• Even after the scan of the side areas is completed, obstacles such as

other vehicles, people or animals that approach from the sides cannot
be detected.

• The sensor is frozen (if it thaws, the system returns to normal). 

A warning message may display at particularly low temperatures due to
the sensor freezing and it may not detect parked vehicles.

• The sensor is blocked by someone’s hand.
• The vehicle is tilted a large amount.
• The temperature is extremely hot or cold.
• The vehicle is driven on undulating roads, slopes, gravel roads, in areas

with tall grass, etc.

• An  ultrasonic  wave  source  is  nearby,  such  as  the  horn  or  sensors  of

another vehicle, a motorcycle engine or the air brake of a large vehicle.

• Heavy rain or a water strikes the vehicle.
• The  angle  of  the  sensor  may  be  deviated  when  assist  control  starts

even  if  there  is  a  parked  vehicle  in  the  target  parking  spot.  Have  the
vehicle inspected at your Toyota dealer.

• Do not install any accessories within the sensor detection range.

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5-5. Using the driving support systems

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Driving assist systems

◆

ECB (Electronically Controlled Brake System)

The electronically controlled system generates braking force corre-
sponding to the brake operation 

◆

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

◆

VSC (Vehicle Stability Control)

Helps  the  driver  to  control  skidding  when  swerving  suddenly  or
turning on slippery road surfaces.

◆

Enhanced VSC (Enhanced Vehicle Stability Control)

Provides cooperative control of the ABS, TRAC, VSC and EPS.
Helps  to  maintain  directional  stability  when  swerving  on  slippery
road surfaces by controlling steering performance.

◆

TRAC (Traction Control) 

Helps  to  maintain  drive  power  and  prevent  the  drive  wheels  from
spinning when starting the vehicle or accelerating on slippery roads

To keep driving safety and performance, the following systems
operate automatically in response to various driving situations.
Be aware, however, that these systems are supplementary and
should not be relied upon too heavily when operating the vehi-
cle. 

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5-5. Using the driving support systems

◆

Hill-start assist control

Helps to reduce the backward movement of the vehicle when start-
ing on an uphill

◆

EPS (Electric Power Steering) 

Employs an electric motor to reduce the amount of effort needed to
turn the steering wheel.

The  slip  indicator  light  will  flash
while  the  TRAC/VSC/ABS  sys-
tems are operating.

If the vehicle gets stuck in mud, dirt or snow, the TRAC system may

reduce power from the hybrid system to the wheels. Pressing 

 to

turn the system off may make it easier for you to rock the vehicle in
order to free it.
To  turn  the  TRAC  system  off,

quickly press and release 

.

The  “Traction  Control  Turned  Off”
will be shown on the multi-informa-
tion display. 

Press 

 

again  to  turn  the  sys-

tem back on.

When the TRAC/VSC/ABS systems are operating

Disabling the TRAC system

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5-5. Using the driving support systems

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■

Turning off both TRAC and VSC systems
To turn the TRAC and VSC systems off, press and hold 

 for more than 3

seconds while the vehicle is stopped.
The VSC OFF indicator light will come on and the “Traction Control Turned
Off” will be shown on the multi-information display.

*

Press 

 again to turn the systems back on.

*

: 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. 663)

■

When the message is displayed on the multi-information display show-

ing that TRAC has been disabled even if 

 has not been pressed

TRAC is temporary deactivated. If the information continues to show, contact
your Toyota dealer.

■

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

●

No more than 2 seconds have elapsed after the brake pedal is released.

■

Sounds and vibrations caused by the ABS, brake assist, VSC, TRAC and
hill-start assist control systems

●

A sound may be heard from the engine compartment when the brake pedal
is depressed repeatedly, when the hybrid system is started or just after the
vehicle begins to move. 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 also after the vehicle comes to a stop.

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5-5. Using the driving support systems

■

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 one or two min-
utes 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.

■

Automatic reactivation of TRAC and VSC systems
After turning the TRAC and VSC systems off, the systems will be automati-
cally re-enabled in the following situations:

●

When the power switch is turned off

●

If only the TRAC system is turned off, the TRAC will turn on when vehicle
speed increases 
If both the TRAC and VSC systems are turned off, automatic re-enabling
will not occur when vehicle speed increases.

■

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.

■

Electric power steering system warning light (warning buzzer)
P. 663

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5-5. Using the driving support systems

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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 roads.

■

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/VSC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC/VSC 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 hill-start assist control. 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 TRAC/ABS/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.

494

5-5. 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  road  condi-
tions. As these are the systems to help ensure vehicle stability 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, tread 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 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.

495

5-6. Driving tips

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Winter driving tips

● Use  fluids  that  are appropriate  to  the  prevailing outside  tempera-

tures. 

• Engine oil
• Engine/power control unit coolant
• Washer fluid

● Have a service technician inspect the condition of the 12-volt bat-

tery.

● Have the vehicle fitted with four snow tires or purchase a set of tire

chains for the front tires. 

Ensure that all tires are the same size and brand, and that chains match
the size of the tires.

Perform the following according to the driving conditions:
● Do not try to forcibly open a window or move a wiper that is frozen.

Pour warm water over the frozen area to melt the ice. Wipe away
the water immediately to prevent it from freezing. 

● To  ensure  proper  operation  of  the  climate  control  system  fan,

remove  any  snow  that  has  accumulated  on  the  air  inlet  vents  in
front of the windshield. 

● Check for and remove any excess ice or snow that may have accu-

mulated  on  the  exterior  lights,  vehicle’s  roof,  chassis,  around  the
tires or on the brakes.

● Remove any snow or mud from the bottom of your shoes before

getting in the vehicle.

Carry  out  the  necessary  preparations  and  inspections  before
driving the vehicle in winter. Always drive the vehicle in a man-
ner appropriate to the prevailing weather conditions. 

Preparation for winter

Before driving the vehicle

496

5-6. Driving tips

Accelerate the vehicle slowly, keep a safe distance between you and
the vehicle ahead, and drive at a reduced speed suitable to road con-
ditions.

Park the vehicle and shift the shift position to P and block the wheel
under the vehicle without setting the parking brake. The parking brake
may  freeze  up,  preventing  it  from  being  released.  If  the  vehicle  is
parked  without  setting  the  parking  brake,  make  sure  to  block  the
wheels.
Failure to do so may be dangerous because it may cause the vehicle
to move unexpectedly, possibly 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 check 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

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■

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 tire chains on the rear
tires.

●

Install tire chains on front tires as tightly as possible. Retighten chains after
driving 1/4 - 1/2 mile (0.5 - 1.0 km).

●

Install tire chains following the instructions provided with the tire chains. 

■

Consumption of fuel and electricity
In cold temperatures, resistance of the parts of a vehicle (transmission, tires,
etc.) generally increases, resulting in increase of energy consumption. As a
result, fuel economy is likely to decrease.
Consumption  of  fuel  and  electricity  of  this  vehicle  is  also  likely  to  become
worse in cold temperatures.

WARNING

■

Driving with snow tires
Observe the following precautions to reduce the risk of accidents. 
Failure to do so may result in a loss of vehicle control and cause 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 accidents. 
Failure to do so may result in the vehicle being unable to be driven safely,
and may cause death or serious injury.

●

Do not drive in excess of the speed limit specified for the tire 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 vehicle con-
trol is maintained.

●

Do not use LDA (Lane Departure Alert with steering control).

■

When parking the vehicle
When parking the vehicle without applying the parking brake, make sure to
chock the wheels.  If you do not  chock the wheels, the vehicle  may  move
unexpectedly, possibly resulting in an accident.

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5-6. Driving tips

NOTICE

■

Repairing or replacing snow tires
Request repairs or replacement of snow tires from Toyota dealers or legiti-
mate tire retailers.
This is because the removal and attachment of snow tires affects the opera-
tion of the tire pressure warning valves and transmitters.

■

Fitting tire chains
The tire pressure warning valves and transmitters may not function correctly
when tire chains are fitted.

499

6

Interior features

6-1. Using the air conditioning 

system and defogger

Automatic air conditioning 

system (vehicles with 
7-inch display)................. 500

Automatic air conditioning 

system (vehicles with 
11.6-inch display)............ 511

Remote Air Conditioning 

System ............................ 522

Heated steering wheel/

seat heaters .................... 526

6-2. Using the interior lights

Interior lights list ................ 528

• Front interior light.......... 529
• Front personal lights ..... 529
• Rear interior light .......... 530

6-3. Using the storage features

List of storage features ..... 531

• Glove box...................... 532
• Console box.................. 532
• Cup holders .................. 533
• Bottle holders/

door pockets ................. 534

• Auxiliary boxes.............. 535
• Seat back pockets ........ 535

Luggage compartment 

features........................... 536

6-4. Using the other interior 

features

Other interior features ....... 540

• Sun visors ..................... 540
• Vanity mirrors................ 540
• Power outlets ................ 541
• USB charging ports....... 542
• Wireless charger........... 544
• Armrest ......................... 553
• Coat hooks.................... 553
• Assist grips ................... 554

Garage door opener.......... 555

500

6-1. Using the air conditioning system and defogger

Automatic air conditioning system (vehi-

cles with 7-inch display)

■

Adjusting the temperature setting
Move  the  temperature  setting
knob  upwards  to  increase  the
temperature and downwards to
decreases the temperature.

If 

 is not pressed, the sys-

tem  will  blow  ambient  tempera-
ture air or heated air.

■

Fan speed setting
Move  the  fan  speed  setting
knob  upwards  to  increase  the
fan  speed  and  downwards  to
decrease the fan speed.

The  fan  speed  is  shown  on  the
display. (7 levels)

Press 

 to turn the fan off.

Air outlets and fan speed are automatically adjusted according
to the temperature setting.

Air conditioning controls

Temperature 
setting knob

Fan speed 
setting knob

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6-1. Using the air conditioning system and defogger

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■

Change the airflow mode
Move  the  airflow  change  knob
upwards  or  downwards  to
change the airflow mode.

The  air  outlets  used  are
switched  each  time  the  knob  is
operated.

Air flows to the upper body
Air  flows  to  the  upper  body
and feet
Air flows to the feet
Air  flows  to  the  feet  and  the
windshield  defogger  oper-
ates

■

S-FLOW mode
In S-FLOW mode, priority for the airflow is given to the front seats,
reducing the airflow and air conditioning effect on the rear seats.
When  a  passenger  is  not  detected  in  the  front  passenger  seat,
depending on the set temperature and ambient temperature, prior-
ity for the airflow will be given to the driver’s seat only.

However, air will always be blown from the side outlet of the front pas-
senger seat.

The following S-FLOW modes are available:



Automatic S-FLOW mode
The system determines whether or not a rear passenger is in the
vehicle by the opening and closing of a rear door. When a rear
passenger is determined to be in the vehicle, S-FLOW mode will
be automatically disabled.
To enable S-FLOW mode again, press 

 and enter manual

S-FLOW mode. (

P. 507)

The 

  indicator  will  illuminate  when  S-FLOW  mode  is

enabled.

Airflow change 
knob

1
2

3
4

502

6-1. Using the air conditioning system and defogger



Manual S-FLOW mode

When 

  is  pressed,  S-FLOW  mode  will  be  manually

enabled/disabled. (

P. 507)

The 

 indicator will illuminate when S-FLOW mode is enabled.

When the power switch is turned to ON mode, the system is oper-
ated in automatic S-FLOW mode.

■

Other functions
● Switching between outside air and recirculated air modes 

(

P. 503)

● Defogging the windshield (P. 504)
● Defogging the rear window and outside rear view mirrors 

(

P. 504)

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6-1. Using the air conditioning system and defogger

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Press 

.

Adjust the temperature setting. (

P. 500)

To stop the operation, press 

.

■

Automatic mode indicator

If the fan speed setting or air flow modes are operated, the 

indicator  goes  off.  However,  automatic  mode  for  functions  other
than that operated is maintained.

■

Switching between outside air and recirculated air modes

Press 

.

The mode switches between outside air mode and recirculated air mode

each time 

 is pressed.

The 

  indicator  illuminates  when  the  recirculated  air  mode  is

selected.

■

Air conditioning eco mode
The air conditioning system is controlled with low fuel consumption
prioritized such as reducing fan speed, etc.

Press 

.

The air conditioning eco mode switches between on and off each time

 is pressed.

“ECO”  is  displayed  on  the  air  conditioning  screen  when  the  air  condi-
tioning eco mode is on.

Using automatic mode

Other functions

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2

3