stop start TOYOTA PRIUS 2021 (in English) Service Manual

PRIUS_OM_OM47E09U_(U)
4134-5. Using the driving support systems
4
Driving
■When the operation is suspended
The maximum number of movements for multi-turn
maneuvering is reached during assist control, or the
target parking spot cannot be reached due to the
control being used on a road with steep grade.
Follow the assist control guidance and use
the system in a wide space that does not have
a steep grade.
MessageSituation/Handling method
MessageSituation/Handling method
The driver holds the
steering wheel during
assist control. 
Stop the vehicle and
rest your hands on the
steering wheel without
applying any force.
Then press the S-APGS
switch to restart assist
control.
The vehicle speed
exceeds 4 mph
(7 km/h) during assist
control.
The S-APGS switch
is pressed while
assist control is tem-
porarily stopped and
the steering wheel is
firmly held. 
Rest your hands on the
steering wheel without
applying any force.
Then stop the vehicle to
restart assist control.
The S-APGS switch
is pressed while
assist control is tem-
porarily stopped and
the vehicle is moving.
Assist control is tem-
porarily stopped
(able to be restarted) 
Stop the vehicle and
rest your hands on the
steering wheel without
applying any force.
Then press the S-APGS
switch to restart assist
control.

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PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
Driving assist systems
◆ECB (Electronically Controlled Brake System)
The electronically controlled system generates braking force co rre-
sponding to the brake operation
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenl y,
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 p edal
is depressed when the system de tects 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 slippe ry
road surfaces by controlling steering performance.
◆TRAC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from
spinning when starting the vehicl e or accelerating on slippery roads
◆Active Cornering Assist (ACA)
Helps to prevent the vehicle from drifting to the outer side by per-
forming inner wheel brake control when attempting to accelerate
while turning
To keep driving safety and perf ormance, the following systems
operate automatically in respon se to various driving situations.
Be aware, however, that these systems are supplementary and
should not be relied upon too heav ily when operating the vehi-
cle.

422
PRIUS_OM_OM47E09U_(U)
4-5. Using the driving support systems
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.
■ 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 will come on and the “Traction Control Tu rned Off”
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 ass ist 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. 593)
■ When the message is displayed on the multi-information display show-
ing that TRAC has been disab led 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 assi st control will
operate:
● The shift position is in a position other than P or N (when sta rting off forward/
backward on an upward incline)
● The vehicle is stopped
● The accelerator pedal is not depressed
● The parking brake is not engaged
Disabling the TRAC system

PRIUS_OM_OM47E09U_(U)
4234-5. Using the driving support systems
4
Driving
■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 re leased.
■ 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 mal function has
occurred in any of these systems.
● Any of the following conditions may occur when the above system s are
operating. None of these indicates that a malfunction has occur red.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard also after the vehicle comes to a s top.
■ 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 brak e pedal
is operated.
● Motor sound of the brake system heard from the front part of th e vehicle
when the driver’s door is opened.
● Operating sound heard from the engine compartment when one or t wo min-
utes passed after the stop of the hybrid system.
■ Active Cornering Assist operation sounds and vibrations
When the Active Cornering Assist is operated, operation sounds and vibra-
tions may be generated from the brake system, but this is not a malfunction.
■ EPS operation sound
When the steering wheel is operated, a motor sound (whirring so und) 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 wh en vehicle
speed increases
If both the TRAC and VSC systems are turned off, automatic re-e nabling
will not occur when vehicle speed increases.

PRIUS_OM_OM47E09U_(U)
4254-5. Using the driving support systems
4
Driving
WARNING
■The ABS does not operate effectively when
● The limits of tire gripping performance have been exceeded (suc h as
excessively worn tires on a snow covered road).
● The vehicle hydroplanes while driving at high speed on wet or s lick 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, espe cially 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. D rive the
vehicle carefully in conditions where stability and power may b e lost.
■ Active Cornering Assist does not operate effectively when
● Do not overly rely on Active Cornering Assist. Active Cornering Assist may
not operate effectively when accelerating down slopes or driving on slip-
pery road surfaces.
● When Active Cornering Assist frequently operates, Active Corner ing
Assist may temporarily stop operating to ensure proper operatio n of the
brakes, TRAC and VSC.
■ Hill-start assist control does not operate effectively when
● Do not overly rely on hill-start assist control. Hill-start ass ist control may
not operate effectively on steep inclines and roads covered wit h ice.
● Unlike the parking brake, hill-start assist control is not inte nded 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.

4425-1. Using the air conditioning system and defogger
PRIUS_OM_OM47E09U_(U)
■Using automatic mode
Fan speed is adjusted automatically according to the temperatur e setting and
the ambient conditions.
Therefore, the fan may stop for a while until warm or cool air is ready to flow
immediately after is pressed.
■ Setting confirmation screen
■ Operation of automatic airflow control
●In order to maintain a comfortable interior, airflow may be directed to seats
without passengers immediately after the hybrid system is start ed and at
other times depending on the outside temperature.
● After the hybrid system is started, if passengers move around i nside or
enter/exit the vehicle, the system cannot accurately detect the presence of
passengers and automatic airflow control will not operate.
■ Operation of manual airflow control
Even if the function is manually switched to directing airflow to only the front
seats, when a rear seat is occupied, it may automatically direc t airflow to all
seats.
■ To return to automatic airflow control
With the indicator off, turn the power switch off.
After 60 minutes or more elapse, turn the power switch to ON.
■ Front seat concentrated airfl ow mode (S-FLOW) operation
■ Changing settings using the multi-information display
The air conditioning system settings can be changed on the scr een of
the multi-information display. ( P. 147)
When changing the settings of the air
conditioning system, the setting confirma-
tion screen is shown as a pop-up on the
multi-information display.
Press of the meter control switches to
go back to the previous screen.
When is pressed, the front seat
concentrated airflow mode (S-FLOW) sta-
tus is displayed on the multi-information
display.
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4525-1. Using the air conditioning system and defogger
PRIUS_OM_OM47E09U_(U)
■Using automatic mode
Fan speed is adjusted automatically according to the temperatur e setting and
the ambient conditions.
Therefore, the fan may stop for a while until warm or cool air is ready to flow
immediately after is selected.
■ Setting confirmation screen
■ Operation of automatic airflow control
●In order to maintain a comfortable interior, airflow may be directed to seats
without passengers immediately after the hybrid system is start ed and at
other times depending on the outside temperature.
● After the hybrid system is started, if passengers move around i nside or
enter/exit the vehicle, the system cannot accurately detect the presence of
passengers and automatic airflow control will not operate.
■ Operation of manual airflow control
Even if the function is manually switched to directing airflow to only the front
seats, when a rear seat is occupied, it may automatically direc t airflow to all
seats.
■ To return to automatic airflow control
With the indicator off, turn the power switch off.
After 60 minutes or more elapse, turn the power switch to ON.
■ Front seat concentrated airfl ow mode (S-FLOW) operation
■ Changing settings using the multi-information display
The air conditioning system settings can be changed on the scr een of
the multi-information display. ( P. 146)
When changing the settings of the air
conditioning system, the setting confirma-
tion screen is shown as a pop-up on the
multi-information display.
Press of the meter control switches to
go back to the previous screen.
When is selected, the front seat
concentrated airflow mode (S-FLOW) sta-
tus is displayed on the multi-information
display.
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2

478
PRIUS_OM_OM47E09U_(U)
5-4. Using the other interior features
■Using the wireless charger
Press the power supply
switch of the wireless char-
ger.
Switches on and off with each
press of the power supply
switch.
When turned on, the operation
indicator light (green) comes on.
Even with the hybrid system off,
the on/off state of the power
supply switch is memorized.
Place the charging side of
the portable device down.
When charging, the operation
indicator light (orange) comes
on.
If charging is not occurring, try
placing the portable device as
close to the center of the
charging area as possible.
When charging is complete, the operation indicator light (green ) comes
on.
● Recharging function
• When charging is complete and after a fixed time in the charge suspension state, c harging restarts.
• When the portable device is moved, charging is stopped for a moment and then it restarts.
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PRIUS_OM_OM47E09U_(U)
4795-4. Using the other interior features
5
Interior features
■Lighting conditions of operation indicator light
*: Depending on the portable device, there are cases where the op eration
indicator light will continue being lit up orange even after the charging is
complete.
● When the operation indi cator light flashes
When an error occurs, the operat ion indicator light flashes an
orange color. Handle the error based on the following table.
Operation indicator lightConditions
Turning offWhen the Wireless charger power supply is
off
Green (comes on)On Standby (charging possible state)
When charging is complete*
Orange (comes on)
When placing the portable device on the
charging area (detecting the portable device)
Charging
Operation indicator
lightSuspected causesHandling method
Flashing repeatedly
once every second
(Orange)Vehicle to charger com-
munication failure.Contact your Toyota
dealer.
Repeatedly flashes
3 times continuously
(Orange)
A foreign substance is
between the portable
device and charge area.
Remove the foreign
substance from
between portable
device and the charge
area.
The portable device is
out of sync due to the
device being shifted from
its position.Place the portable
device near the center
of the charge area.
Repeatedly flashes
4 times continuously
(Orange)Temperature rising
within the wireless char-
ger.Stop charging at once
and start charging
again after for a while.

554
PRIUS_OM_OM47E09U_(U)
6-3. Do-it-yourself maintenance
■Scheduled maintenance of the air intake vent is necessary when
In some situations such as when the vehicle is used frequently or in heavy
traffic or dusty areas, the air intake vent may need to be clea ned more regu-
larly. For details, refer to the “Scheduled Maintenance Guide” or “Owner’s
Manual Supplement”.
■ Cleaning the air intake vent
●Dust in the air intake vent may interfere with the cooling of t he hybrid battery
(traction battery). If charging/discharging of the hybrid batte ry (traction bat-
tery) becomes limited, the distance that the vehicle can be dri ven using the
electric motor (traction motor) may be reduced and the fuel eco nomy may
be reduced. Inspect and clean the air intake vent periodically.
● Improper handling of the air intake vent cover and filter may result in dam-
age to them. If you have any concerns about cleaning the filter , contact your
Toyota dealer.
■ If “Maintenance required for Traction battery cooling parts See owner’s
manual” is shown on the mu lti-information display
● If this warning message is shown on the multi-information displ ay, remove
the air intake vent cover and clean the filter. ( P. 551)
● After cleaning the air intake vent, start the hybrid system and check that the
warning message is no longer shown.
It may take approximately 20 minutes after the hybrid system is started until
the warning message disappears. If the warning message does not disap-
pear, have the vehicle inspected by your Toyota dealer.
WARNING
■ When cleaning the air intake vent
● Do not use water or other liquids to clean the air intake vent. If water is
applied to the hybrid battery (traction battery) or other components, a mal-
function or fire may occur.
● Before cleaning the air intake vent, make sure to turn the power switch off
to stop the hybrid system.
■ When removing the air intake vent cover
Do not touch the service plug located near the air intake vent. ( P. 91)