warning light TOYOTA PRIUS PLUG-IN HYBRID 2021 Service Manual

4305-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
■Before using LTA system
● Do not rely solely upon the LTA system. The LTA system does not auto-
matically drive the vehicle or reduce the amount of attention that must be
paid to the area in front of the vehicle. The driver must always assume full
responsibility for driving safely by paying careful attention to the surround-
ing conditions and operating the steering wheel to correct the path of the
vehicle. Also, the driver must take adequate breaks when fatigued, such
as from driving for a long period of time.
● Failure to perform appropriate driving operations and pay careful attention
may lead to an accident, resulting in death or serious injury.
● When not using the LTA system, use the LTA switch to turn the system off.
■ Situations unsuitable for LTA system
In the following situations, use the LTA switch to turn the system off. Failure
to do so may lead to an accident, resulting in death or serious injury.
● Vehicle is driven on a road surface which is slippery due to rainy weather,
fallen snow, freezing, etc.
● Vehicle is driven on a snow-covered road.
● White (yellow) lines are difficult to see due to rain, snow, fog, dust, etc.
● Vehicle is driven in a temporary lane or restricted lane due to construction
work.
● Vehicle is driven in a construction zone.
● A spare tire, tire chains, etc. are equipped.
● When the tires have been excessively worn, or when the tire inflation pres-
sure is low.
● During emergency towing.
■ Preventing LTA system malfunctions and operations performed by
mistake
● Do not modify the headlights or place stickers, etc. on the surface of the
lights.
● Do not modify the suspension etc. If the suspension etc. needs to be
replaced, contact any authorized Toyota retailer or Toyota authorized
repairer, or any reliable repairer.
● Do not install or place anything on the hood or grille. Also, do not install a
grille guard (bull bars, kangaroo bar, etc.).
● If your windshield needs repairs, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.

4325-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
●There are shadows on the road that run parallel with, or cover, the white
(yellow) lines.
● The vehicle is driven in an area without white (yellow) lines, such as in
front of a tollgate or checkpoint, or at an intersection, etc.
● The white (yellow) lines are cracked, “Raised pavement marker” or stones
are present.
● The white (yellow) lines cannot be seen or are difficult to see due to sand,
etc.
● The vehicle is driven on a road surface that is wet due to rain, puddles,
etc.
● The traffic lines are yellow (which may be more difficult to recognize than
lines that are white).
● The white (yellow) lines cross over a curb, etc.
● The vehicle is driven on a bright surface, such as concrete.
● If the edge of the road is not clear or straight.
● The vehicle is driven on a surface that is bright due to reflected light, etc.
●Vehicle is driven where the road
diverges, merges, etc.
● Repair marks of asphalt, white (yellow)
lines, etc. are present due to road
repair.

4335-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
5
Driving
WARNING
● The vehicle is driven in an area where the brightness changes suddenly,
such as at the entrances and exits of tunnels, etc.
● Light from the headlights of an oncoming vehicle, the sun, etc. enters the
camera.
● The vehicle is driven on a slope.
● The vehicle is driven on a road which tilts left or right, or a winding road.
● The vehicle is driven on an unpaved or rough road.
● The traffic lane is excessively narrow or wide.
● The vehicle is extremely tilted due to carrying heavy luggage or having
improper tire pressure.
● The distance to the preceding vehicle is extremely short.
● The vehicle is moving up and down a large amount due to road conditions
during driving (poor roads or road seams).
● When driving in a tunnel or at night with the headlights off or when a head-
light is dim due to its lens being dirty or it being misaligned.
● The vehicle is struck by a crosswind.
● The vehicle is affected by wind from a vehicle driven in a nearby lane.
● The vehicle has just changed lanes or crossed an intersection.
● Tires which differ by structure, manufacturer, brand or tread pattern are
used.
● When tires of a size other than specified are installed.
● Snow tires, etc. are equipped.
● The vehicle is being driven at extremely high speeds.

4565-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver.
Example of deceleration cruising and follow-up cruising
When a preceding vehicle driving slower than the set speed
appears
When a vehicle is detected running ahead of you, the system automatically
decelerates your vehicle. When a greater reduction in vehicle speed is
necessary, the system applies the brakes (the stop lights will come on at
this time). The system will respond to changes in the speed of the vehicle
ahead in order to maintain the vehicle-to-vehicle distance set by the driver.
Approach warning warns you when the system cannot decelerate suffi-
ciently to prevent your vehicle from closing in on the vehicle ahead.
When the vehicle ahead of you stops, your vehicle will also stop (vehicle is
stopped by system control). After the vehicle ahead starts off, pushing the
cruise control lever up or depressing the accelerator pedal (start-off opera-
tion) will resume follow-up cruising. If the start-off operation is not per-
formed, system control continues to keep your vehicle stopped.
When the turn signal lever is operated and your vehicle moves to an over-
taking lane while driving at 80 km/h (50 mph) or more, the vehicle will
accelerate to help to overtake a passing vehicle.
The system’s identification of what is an overtaking lane may be deter-
mined solely based on the location of the steering wheel in the vehicle (left
side driver position versus right side driver position.) If the vehicle is driven
to a region where the overtaking lane is on a different side from where the
vehicle is normally driven, the vehicle may accelerate when the turn signal
lever is operated in the opposite direction to the overtaking lane (e.g., if the
driver normally operates the vehicle in a region where the overtaking lane
is to the right but then drives to a region where the overtaking lane is to the
left, the vehicle may accelerate when the right turn signal is activated).
Example of acceleration
When there are no longer any preceding vehicles driving slower
than the set speed
The system accelerates until the set speed is reached. The system then
returns to constant speed cruising.
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4885-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
■Handling the radar sensor
● Keep the sensor and its surrounding area on the bumper clean at all times.
● Do not subject a sensor or its surrounding area on the rear bumper to a
strong impact.
If a sensor is moved even slightly off position, the system may malfunction
and vehicles may not be detected correctly.
In the following situations, have your vehicle inspected by any authorized
Toyota retailer or Toyota authorized repairer, or any reliable repairer.
• A sensor or its surrounding area is subject to a strong impact.
• If the surrounding area of a sensor is scratched or dented, or part of
them has become disconnected.
● Do not disassemble the sensor.
● Do not attach accessories or stickers to the sensor or surrounding area on
the bumper.
● Do not modify the sensor or surrounding area on the bumper.
● Do not paint the rear bumper any color other than an official Toyota color.
One Blind Spot Monitor sensor is
installed inside the left and right side of
the vehicle rear bumper respectively.
Observe the following to ensure the Blind
Spot Monitor can function correctly.

5075-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
5
Driving
WARNING
■ Sensors
Certain vehicle conditions and the surrounding environment may affect the
ability of the sensor to correctly detect obstacles. Particular instances where
this may occur are listed below.
● There is dirt, snow or ice on the sensor. (Wiping the sensors will resolve
this problem.)
● The sensor is frozen. (Thawing the area will resolve this problem.)
In especially cold weather, if a sensor is frozen, the screen may show an
abnormal display, or obstacles may not be detected.
● The sensor is covered in any way.
● In harsh sunlight or intense cold weather
● On an extremely bumpy road, on an incline, on gravel, or on grass
● The vicinity of the vehicle is noisy due to vehicle horns, motorcycle
engines, air brakes of large vehicles , or other loud noises producing ultra-
sonic waves.
● The sensor is splashed with water or drenched with heavy rain.
● The sensor is drenched with water on a flooded road.
● The vehicle is leaning considerably to one side.
● The vehicle is equipped with a fender pole or wireless antenna.
● The vehicle is approaching a tall or curved curb.
● The area directly under the bumpers is not detected.
● If obstacles draw too close to the sensor.
● The bumper or sensor receives a strong impact.
● A non-genuine Toyota suspension (lowered suspension etc.) is installed.
● There is another vehicle equipped with parking assist sensors in the vicin-
ity.
● Towing eyelets are installed.
● A backlit license plate is installed.
In addition to the examples above, depending on the shape and condition of
obstacles, detection may not be possible, or the detection range may be
shortened.

5205-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
●Influence from other sonic waves
• An ultrasonic wave source is nearby, such as the horn or parking assist-
sensors of another vehicle, a vehicle detector, a motorcycle engine or the
air brake of a large vehicle
• Electronic components (such as a backlit license plate (especially fluo-
rescent types), fog lights, a fender pole or a wireless antenna) are
installed near the sensors
●Changes in the vehicle
• When driving with the shift position in N
• The vehicle is tilted a large amount
• The height of the vehicle has drastically changed due to the carried load
(the nose tilts up or down)
• The direction of the sensor has deviated due to a collision or other impact
■Parking Support Brake function while the Simple Intelligent Parking
Assist System is operating
P. 525
■When removing and installing the 12-volt battery
The system needs to be initialized.
The system can be initialized by driving the vehicle straight ahead for 5 sec-
onds or more at a speed of approximately 35 km/h (22 mph) or higher.
■When “PKSB Unavailable” is displayed on the multi-information display
and the PKSB OFF indicator flashes
●Ice, snow, dirt, etc., may have adhered to the sensor. If this occurs, remove
the ice, snow, dirt, etc., from the sensor to return the system to normal.
Also, a warning message may be displayed at low temperatures due to ice
forming on the sensor, and the sensor may not detect obstacles. Once the
ice melts, the system will return to normal.
●If this message is shown even after removing dirt from the sensor, or shown
when the sensor was not dirty to begin with, have the vehicle inspected at
any authorized Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
●System initialization may not have been performed after removal and instal-
lation of the 12-volt battery. Perform system initialization.
■When “PKSB Malfunction Visit Your Dealer” is displayed on the multi-
information display, the PKSB OFF indicator flashes and the buzzer
sounds
The system may not be operating properly. Have the vehicle inspected at any
authorized Toyota retailer or Toyota authorized repairer, or any reliable
repairer.

5615-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
5
Driving
If the vehicle gets stuck in mud, dirt or snow, the TRC 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 TRC system off, quickly press and release .
The “Traction Control Turned Off” will be shown on the multi-information
display.
Press again to turn the system back on.
■ Turning off both TRC and VSC systems
To turn the TRC 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 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. 7 1 6 )
■ When the message is displayed on the multi-information display show-
ing that TRC has been disable d even if has not been pressed
TRC is temporary deactivated. If the information continues to show, contact
any authorized Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
Disabling the TRC system
Vehicles without panoramic
view monitor
Vehicles with panoramic view
monitor

5635-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
5
Driving
■Automatic reactivation of TRC and VSC systems
After turning the TRC and VSC systems off, the systems will be automatically
re-enabled in the following situations:
●When the power switch is turned off
●If only the TRC system is turned off, the TRC will turn on when vehicle
speed increases
If both the TRC 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. 715
■Operating conditions of emergency brake signal
When the following conditions are met, the emergency brake signal will oper-
ate:
●The emergency flashers are off.
●Actual vehicle speed is over 55 km/h (35 mph).
●The system judges from the vehicle deceleration that this is a sudden brak-
ing operation.
■Automatic system cancelation of emergency brake signal
The emergency brake signal will be canceled in any of the following situa-
tions:
●The emergency flashers are turned on.
●The system judges from the vehicle deceleration that is not a sudden brak-
ing operation.

5645-5. Using the driving support systems
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
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 t he 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
■ TRC/VSC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRC/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 TRC/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.