
831-4. Theft deterrent system
PRIUS PRIME_OM_OM47C77U_(U)
1
For safety and security
Immobilizer system
The indicator light flashes after
the power switch has been turned
off to indicate that the system is
operating.
The indicator light stops flashing
after the power switch has been
turned to ACCESSORY or ON
mode to indicate that the system
has been canceled.
■System maintenance
The vehicle has a maintenance-free type immobilizer system.
■ Conditions that may cause the system to malfunction
●If the grip portion of the key is in contact with a metallic ob ject
● If the key is in close proximity to or touching a key registered to the security
system (key with a built-in transponder chip) of another vehicle
The vehicle’s keys ha ve built-in transponder chips that prevent
the hybrid system from starting if a key has not been previousl y
registered in the vehic le’s on-board computer.
Never leave the keys inside the vehicle when you leave the vehi-
cle. This system is designed to help prevent vehicle theft but does not
guarantee absolute security against all vehicle thefts.

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PRIUS PRIME_OM_OM47C77U_(U)
3. Instrument cluster
Warning lights inform the driver of malfunctions in any of the vehicle’s
systems.
Warning lights
Warning lightsPages
*1Brake system warning light (U.S.A.) P. 662
*1Brake system warning light (Canada)
(Red)P. 662
*1Brake system warning light
(Yellow)P. 662
*1Charging system warning light
P. 662
*1Low engine oil pressure warning lightP. 662
*1Malfunction indicator lamp (U.S.A.) P. 662
*1Malfunction indicator lamp (Canada)P. 662
*1SRS warning light P. 663
*1ABS warning light (U.S.A.) P. 663
*1ABS warning light (Canada)P. 663
*1Electric power steering system warning light
(Red/yellow)P. 663
*1, 2PCS warning light
P. 663
*1Slip indicator lightP. 663
*1High coolant temperature warning lightP. 664

208
PRIUS PRIME_OM_OM47C77U_(U)
3. Instrument cluster
■BSM (Blind Spot Monitor) outsid e rear view mirror indicators
(if equipped) ( P. 421)
• When the BSM function is enabled on the screen of the multi-infor- mation display, the power switch is turned to ON mode.
If the system is functioning correctly, the BSM outside rear vi ew mirror indi-
cators will turn off after a few seconds.
If the BSM outside rear view mirror indicators do not illuminat e or do not
turn off, there may be a malfunction in the system.
If this occurs, have the vehicle inspected by your Toyota deale r.
●
Indicators are also displayed on the out-
side rear view mirrors.
● In order to confirm operation, the BSM
outside rear view mirror indicators illumi-
nate in the following situations:
• When the power switch is in ON
mode, the BSM function is enabled
on the screen of the multi-infor-
mation display.
WARNING
■If a safety system warning light does not come on
Should a safety system light such as the ABS and SRS warning li ght not
come on when you start the hybrid system, this could mean that these sys-
tems are not available to help protect you in an accident, which could result
in death or serious injury. Have the vehicle inspected by your Toyota dealer
immediately if this occurs.
NOTICE
■To prevent damage to the engine and its components
The engine may be overheating if the high coolant temperature warning
light comes on or flashes. In this case, immediately stop the v ehicle in a
safe place, and check the engine after it has cooled completely. (P. 709)

398
PRIUS PRIME_OM_OM47C77U_(U)
5-5. Using the driving support systems
■Operation conditions of each function
●Lane departure alert function
This function operates when all of the following conditions are met.
• LDA is turned on.
• Vehicle speed is approximately 32 mph (50 km/h) or more.
• System recognizes white (yellow) lines.
• Width of traffic lane is approximately 9.8 ft. (3 m) or more.
• Turn signal lever is not operated.
• Vehicle is driven on a straight road or around a gentle curve with a radius
of more than approximately 492 ft. (150 m).
• No system malfunctions are detected. ( P. 401)
● Steering control function
This function operates when all of the following conditions are met in addi-
tion to the operation conditions for the lane departure alert function.
• Setting for (“LDA Steering Assist Mode”) in the screen of
the multi-information display is set to “On”. ( P. 218)
• Vehicle is not accelerated or decelerated by a certain amount or more.
• Steering wheel is not operated with a steering force level suitable for changing lanes.
• ABS, VSC, TRAC and PCS are not operating.
• TRAC or VSC is not turned off.
● Vehicle sway warning function
This function operates when all of the following conditions are met.
• Setting for (“Lane Sway Warning Status”) in the screen of the multi-information display is set to “On”. ( P. 218)
• Vehicle speed is approximately 32 mph (50 km/h) or more.
• Width of traffic lane is approximately 9.8 ft. (3 m) or more.
• No system malfunctions are detected. ( P. 401)
■ Temporary cancellation of functions
When the operation conditions are no longer met, a function may be tempo-
rarily canceled. However, when the operation conditions are met again, oper-
ation of the function is automatically restored. ( P. 398)
■ Steering control function
Depending on the vehicle speed, lane departure situation, road conditions,
etc., the driver may not feel the function is operating or the function may not
operate at all.

PRIUS PRIME_OM_OM47C77U_(U)
4055-5. Using the driving support systems
5
Driving
WARNING
■Cautions regarding the driving assist systems
Observe the following precautions, as there are limitations to the assistance
provided by the system.
Failure to do so may cause an accident resulting in death or se rious injury.
● Assisting the driver to measure following distance
The dynamic radar cruise control with full-speed range is only intended to
help the driver in determining the following distance between the driver’s
own vehicle and a designated vehicle traveling ahead. It is not a mecha-
nism that allows careless or inattentive driving, and it is not a system that
can assist the driver in low-visibility conditions. It is still necessary for
driver to pay close attention to the vehicle’s surroundings.
● Assisting the driver to judge proper following distance
The dynamic radar cruise control with full-speed range determines
whether the following distance between the driver’s own vehicle and a
designated vehicle traveling ahead is within a set range. It is not capable
of making any other type of judgement. Therefore, it is absolutely neces-
sary for the driver to remain vigilant and to determine whether or not there
is a possibility of danger in any given situation.
● Assisting the driver to operate the vehicle
The dynamic radar cruise control with full-speed range does not include
functions which will prevent or avoid collisions with vehicles ahead of your
vehicle. Therefore, if there is ever any possibility of danger, the driver must
take immediate and direct control of the vehicle and act appropriately in
order to ensure the safety of all involved.

PRIUS PRIME_OM_OM47C77U_(U)
4415-5. Using the driving support systems
5
Driving
WARNING
■Side sensors
In the following situations, the intuitive parking assist may n ot operate nor-
mally and may result in an unexpected accident. Drive carefully.
● Obstacles may not be detected in the side areas until the vehicle is driven
for a short time and a scan of the side areas is completed. ( P. 438)
● Even after the scan of the side areas is completed, obstacles s uch as
other vehicles, people or animals that approach from the sides cannot be
detected.
● Even after the scan of the side areas is completed, obstacles may not be
detected depending on the surrounding situation of the vehicle.
At that time, the side sensor operation displays ( P. 434) temporary turn
off.
■ Obstacles which may not be properly detected
The shape of the obstacle may prevent the sensor from detecting it. Pay
particular attention to the following obstacles:
● Wires, fences, ropes, etc.
● Cotton, snow and other materials that absorb sound waves
● Sharply-angled objects
● Low obstacles
● Tall obstacles with upper sections projecting outwards in the direction of
your vehicle
● People may not be detected if they are wearing certain types of clothing.
● Moving objects such as people or animals

489
PRIUS PRIME_OM_OM47C77U_(U)
5-5. Using the driving support systems
5
Driving
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
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.

490
PRIUS PRIME_OM_OM47C77U_(U)
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