2023 TOYOTA PRIUS ECU

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1-4. Hybrid system
PRIUS_OM_OM47F32E_(EE)
For safety and security
Hybrid system features
The illustration is an example for explanation and may differ from the
actual item.
Gasoline engine
Front electric motor (traction motor)
Rear electric motor (traction motor)*
*: AWD models only
Your vehicle is a hybrid vehicle. It has characteristics different
from conventional vehicles. Be sure you are closely familiar with
the characteristics of your vehicle, and operate it with care.
The hybrid system combines the use of a gasoline engine and
an electric motor (traction motor) according to driving condi-
tions, improving fuel efficiency and reducing exhaust emis-
sions.
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811-4. Hybrid system
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PRIUS_OM_OM47F32E_(EE)
For safety and security
■Regenerative braking
● In the following situations, kinetic energy is converted to electric energy and
deceleration force can be obtained in c onjunction with the recharging of the
hybrid battery (traction battery).
• The accelerator pedal is released while driving with the shift position in D
or B.
• The brake pedal is depressed while driv ing with the shift position in D or
B.
● Vehicles with GPF system: While the GPF system (P. 440) is operating to
regenerate the exhaust gas filter, the hybrid battery (traction battery) may
not be recharged.
■ Hybrid System Indicator
■ Conditions in which the gasoline engine may not stop
The gasoline engine starts and stops automatically. However, it may not stop
automatically in the following conditions*:
● During gasoline engine warm-up
● During hybrid battery (traction battery) charging
● When the temperature of the hybrid battery (traction battery) is high or low
● When the heater is switched on
*: Depending on the circumstances, the gasoline engine may also not stop
automatically in situations other than those above.
■ Charging the hybrid battery (traction battery)
As the gasoline engine charges the hybrid battery (traction battery), the bat-
tery does not need to be charged from an outside source. However, if the
vehicle is left parked for a long time the hybrid battery (traction battery) will
slowly discharge. For this reason, be sure to drive the vehicle at least once
every few months for at least 30 minutes or 16 km (10 miles). If the hybrid
battery (traction battery) becomes fully discharged and you are unable to start
the hybrid system, contact any authorized Toyota retailer or Toyota authorized
repairer, or any reliable repairer.
■ Charging the 12-volt battery
 P. 641
Hybrid System Indicator represents the
hybrid system power output and regener-
ative charging. ( P. 132)

831-4. Hybrid system
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PRIUS_OM_OM47F32E_(EE)
For safety and security
■Maintenance, repair, recycling, and disposal
Contact any authorized Toyota retailer or Toyota authorized repairer, or any
reliable repairer regarding maintenance, repair, recycling and disposal. Do
not dispose of the vehicle yourself.

851-4. Hybrid system
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PRIUS_OM_OM47F32E_(EE)
For safety and security
There is an air intake vent under
the right side of the rear seat for
the purpose of cooling the hybrid
battery (traction battery). If the
vent is blocked, charging/dis-
charging of the hybrid battery
(traction battery) may become lim-
ited.
When a certain level of impact is detected by the impact sensor, the
emergency shut off system blocks the high voltage current and stops
the fuel pump to minimize the risk of electrocution and fuel leakage. If
the emergency shut off system activates, your vehicle will not restart.
To restart the hybrid system, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
A message is automatically displayed when a malfunction occurs in
the hybrid system or an improper operation is attempted.
If a warning message is shown on
the multi-information display, read
the message and follow the
instructions.
Hybrid battery (traction battery) air intake vent
Emergency shut off system
Hybrid warning message

871-4. Hybrid system
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PRIUS_OM_OM47F32E_(EE)
For safety and security
WARNING
■High voltage precautions
This vehicle has high voltage DC and AC systems as well as a 12-volt sys-
tem. DC and AC high voltage is very dangerous and can cause severe
burns and electric shock that may result in death or serious injury.
● Never touch, disassemble, remove or replace the high voltage parts,
cables or their connectors.
● The hybrid system will become hot after starting as the system uses high
voltage. Be careful of both the high voltage and the high temperature, and
always obey the warning labels attached to the vehicle.
● Never try to open the service plug
access hole located under the right side
of the rear seat. The service plug is
used only when the vehicle is serviced
and is subject to high voltage.

891-4. Hybrid system
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PRIUS_OM_OM47F32E_(EE)
For safety and security
WARNING
■Hybrid battery (traction battery)
● Never resell, hand over or modify the hybrid battery. To prevent accidents,
hybrid batteries that have been removed from a disposed vehicle are col-
lected through any authorized Toyota retailer or Toyota authorized repairer,
or any reliable repairer. Do not dispose of the battery yourself.
Unless the battery is properly collected, the following may occur, resulting
in death or serious injury:
• The hybrid battery may be illegally disposed of or dumped, and it is haz-
ardous to the environment or someone may touch a high voltage part,
resulting in an electric shock.
• The hybrid battery is intended to be used exclusively with your hybrid
vehicle. If the hybrid battery is used outside of your vehicle or modified
in any way, accidents such as electric shock, heat generation, smoke
generation, an explosion and electrolyte leakage may occur.
When reselling or handing over your vehicle, the possibility of an accident
is extremely high because the person receiving the vehicle may not be
aware of these dangers.
● If your vehicle is disposed of without the hybrid battery having been
removed, there is a danger of serious electric shock if high voltage parts,
cables and their connectors are touched. In the event that your vehicle
must be disposed of, the hybrid battery must be disposed of by any autho-
rized Toyota retailer or Toyota authorized repairer, or any reliable repairer
or a qualified service shop. If the hybrid battery is not disposed of properly,
it may cause electric shock that can result in death or serious injury.

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1-5. Theft deterrent system
PRIUS_OM_OM47F32E_(EE)
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 object
● 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 have built-in transponder chips that prevent
the hybrid system from starting if a key has not been previously
registered in the vehicle’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.
NOTICE
■ To ensure the system operates correctly
Do not modify or remove the system. If modified or removed, the proper
operation of the system cannot be guaranteed.

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1-5. Theft deterrent system
PRIUS_OM_OM47F32E_(EE)
For safety and security
Alar m
The alarm uses light and sound to give an alert when an intrusion is
detected.
The alarm is triggered in the following situations when the alarm is
set:
● A locked door or back door is unlocked or opened in any way other
than using the entry function or wireless remote control. (The doors
will lock again automatically.)
● The hood is opened.
● If equipped, the intrusion sensor detects something moving inside
the vehicle. (An intruder gets in the vehicle.)
Close the doors and hood, and
lock all the doors using the entry
function or wireless remote con-
trol. The system will be set auto-
matically after 30 seconds.
The indicator light changes from
being on to flashing when the sys-
tem is set.
Do one of the following to deactivate or stop the alarm.
● Unlock the doors using the entry function or wireless remote con-
trol.
● Start the hybrid system. (The alarm will be deactivated or stopped
after a few seconds.)
: If equipped
The alarm
Setting the alarm system
Deactivating or stopping the alarm