2022 TOYOTA PRIUS ECU

831-3. Emergency assistance
PRIUS_OM_OM47F01U_(U)
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For safety and security

851-4. Hybrid system
PRIUS_OM_OM47F01U_(U)
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For safety and security
◆When stopped/during start off
The gasoline engine stops
* when the vehicle is stopped. During
start off, the electric motor (traction motor) drives the vehic le. At
slow speeds or when traveling down a gentle slope, the engine i s
stopped
* and the electric motor (tr action motor) is used.
When shift position is in N, the hybrid battery (traction batte ry) is not
being charged.
*: When the hybrid battery (traction battery) requires charging o r the engine
is warming up, etc., the gasoline engine will not automatically stop.
( P. 87)
◆During normal driving
The gasoline engine is predominantly used. The electric motor
(traction motor) charges the hybr id battery (traction battery) as nec-
essary.
◆When accelerating sharply
When the accelerator pedal is depressed heavily, the power of t he
hybrid battery (traction battery) is added to that of the gasol ine
engine via the electric motor (traction motor).
◆When braking (regenerative braking)
The wheels operate the electric motor (traction motor) as a pow er
generator, and the hybrid battery (traction battery) is charged.
When driving with the gasolin e engine stopped, a sound, which
changes in accordance with the driving speed, will be played in order
to warn people nearby of the vehicle’s approach. The sound will stop
when the vehicle speed exceeds approximately 22 mph (35 km/h).
Vehicle proximity notification system

871-4. Hybrid system
PRIUS_OM_OM47F01U_(U)
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For safety and security
■Regenerative braking
In the following situations, kinetic energy is converted to electric energy and
deceleration force can be obtained in conjunction with the rech arging 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 driving with the shift posit ion in D or B.
■ 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 batt ery (traction battery)
As the gasoline engine charges the hybrid battery (traction bat tery), the bat-
tery does not need to be charged from an outside source. Howeve r, i f t h e
vehicle is left parked for a long time the hybrid battery (trac tion 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 10 miles (16 km). I f the hybrid
battery (traction battery) becomes fully discharged and you are unable to start
the hybrid system, contact your Toyota dealer.
■ Charging the 12-volt battery
P. 648
■ After the 12-volt battery has discharged or when the terminal h as been
removed and installed during exchange, etc.
The gasoline engine may not stop even if the vehicle is being driven by the
hybrid battery (traction battery). If this continues for a few days, contact your
Toyota dealer. Hybrid System Indicator represents the
hybrid system power output and regener-
ative charging. ( P. 129)

891-4. Hybrid system
PRIUS_OM_OM47F01U_(U)
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For safety and security
Hybrid system precautions
The illustration is an example for explanation and may differ from the
actual item.
Take care when handling the hybrid system, as it is a high volt -
age system (about 600 V at maximum) as well as contains parts
that become extremely hot when the hybrid system is operating.
Obey the warning labels attached to the vehicle.
Warning label
Service plug
Rear inverter (traction motor)
*
Rear electric motor (traction
motor)
*
Hybrid battery (traction battery) High voltage c
ables (orange)
Front electric motor (traction
motor)
Power control unit
Air conditioning compressor*: AWD models only
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2
3
4
5
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7
8
9

911-4. Hybrid system
PRIUS_OM_OM47F01U_(U)
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For safety and security
■If a warning light comes on, a warning message is displayed, or the
12-volt battery is disconnected
The hybrid system may not start. In this case, try to start the system again. If
the “READY” indicator does not come on, contact your Toyota dea ler.
■ Running out of fuel
When the vehicle has run out of fuel and the hybrid system cann ot be started,
refuel the vehicle with at least enough gasoline to make the lo w fuel level
warning light ( P. 590) go off. If there is only a small amount of fuel, the
hybrid system may not be able to start. (The standard amount of fuel is about
2.0 gal. [7.5 L, 1.7 Imp.gal.], when the vehicle is on a level surface. This value
may vary when the vehicle is on a slope. Add extra fuel when th e vehicle is
inclined.)
■ Electromagnetic waves
●High voltage parts and cables on hybrid vehicles incorporate el ectromag-
netic shielding, and therefore emit approximately the same amount of elec-
tromagnetic waves as conventional gasoline powered vehicles or home
electronic appliances.
● Your vehicle may cause sound interference in some third party-p roduced
radio parts.
■ Hybrid battery ( traction battery)
The hybrid battery (traction battery) has a limited service life. The lifespan of
the hybrid battery (traction battery) can change in accordance with driving
style and driving conditions.
■ Starting the hybrid system in a n extremely cold environment
When the hybrid battery (traction battery) is extremely cold (b elow approxi-
mately -22°F [-30°C]) under the influence of the outside temper ature, it may
not be possible to start the hybrid system. In this case, try to start the hybrid
system again after the temperature of the hybrid battery increases due to the
outside temperature increase etc.

931-4. Hybrid system
PRIUS_OM_OM47F01U_(U)
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For safety and security
WARNING
■Road accident cautions
Observe the following precautions to reduce the risk of death o r serious
injury:
● Pull your vehicle off the road, apply the parking brake, shift the shift posi-
tion to P, and turn the hybrid system off.
● Do not touch the high voltage parts, cables and connectors.
● If electric wires are exposed inside or outside your vehicle, an electric
shock may occur. Never touch exposed electric wires.
● If a fire occurs in the hybrid vehicle, leave the vehicle as soon as possible.
Never use a fire extinguisher that is not meant for electric fires. Using even
a small amount of water may be dangerous.
● If your vehicle needs to be towed, do so with front wheels (2WD models)
or four wheels (AWD models) raised. If the wheels connected to the elec-
tric motor (traction motor) are on the ground when towing, the motor may
continue to generate electricity. This may cause a fire. ( P. 580)
● Carefully inspect the ground under the vehicle. If you find that liquid has
leaked onto the ground, the fuel system may have been damaged. Leave
the vehicle as soon as possible.
AWD models
● If a fluid leak occurs, do not touch the fluid as it may be strong alkaline
electrolyte from the hybrid battery (traction battery). If it comes into contact
with your skin or eyes, wash it off immediately with a large amount of water
or, if possible, boric acid solution. Seek immediate medical attention.
2WD models
● Do not touch the battery if liquid is leaking from or adhering to it.
If electrolyte (carbonic-based organic electrolyte) from the hy brid battery
(traction battery) comes into contact with the eyes or skin, it could cause
blindness or skin wounds. In the unlikely event that it comes into contact
with the eyes or skin, wash it off immediately with a large amount of water,
and seek immediate medical attention.
● If electrolyte is leaking from the hybrid battery (traction bat tery), do not
approach the vehicle.
Even in the unlikely event that the hybrid battery (traction ba ttery) is dam-
aged, the internal construction of the battery will prevent a l arge amount of
electrolyte from leaking out. However, any electrolyte that doe s leak out
will give off a vapor. This vapor is an irritant to skin and eyes and could
cause acute poisoning if inhaled.
● Do not bring burning or high-tem perature items close to the electrolyte.
The electrolyte may ignite and cause a fire.

951-4. Hybrid system
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For safety and security
NOTICE
■Hybrid battery (traction battery) air intake vent
● Make sure not to block the air intake vent with anything, such as a seat
cover, plastic cover, or luggage. If the vent is blocked, the charging/dis-
charging of the hybrid battery (traction battery) may become limited.
● When dust etc. has accumulated in the air intake vent, clean it with a vac-
uum cleaner to prevent the vent from clogging.
● Do not get water or foreign materials in the air intake vent as this may
cause a short circuit and damage the hybrid battery (traction battery).
● Do not carry large amounts of water such as water cooler bottle s in the
vehicle. If water spills onto the hybrid battery (traction batt ery), the battery
may be damaged. Have the vehicle inspected by your Toyota deale r.
● There is a filter installed to the air intake vent. When the fi lter remains
noticeably dirty even after cleaning the air intake vent, filte r cleaning or
replacement is recommended. For information regarding filter cl eaning or
replacement, refer to P. 546.
● If “Maintenance Required for Traction Battery Cooling Parts See Owner’s
Manual” is shown on the multi-information display, the air intake vent and
filter may be clogged. Refer to P. 546 for information on how to clean the
air intake vent.

961-5. Theft deterrent system
PRIUS_OM_OM47F01U_(U)
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 vehicl e
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.