maintenance TOYOTA PRIUS PLUG-IN HYBRID 2021 Owner's Guide

6387-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
With the engine at operating temperature and turned off, check the oil
level on the dipstick.
■Checking the engine oil
Park the vehicle on level ground. After warming up the engine
and turning off the hybrid system, wait more than 5 minutes for
the oil to drain back into the bottom of the engine.
Holding a rag under the end,
pull the dipstick out.
Wipe the dipstick clean.
Reinsert the dipstick fully.
Holding a rag under the end, pull the dipstick out and check the
oil level.
Low
Normal
Excessive
Wipe the dipstick and reinsert it fully.
Engine oil
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5
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6397-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
■Adding engine oil
If the oil level is below or near
the low level mark, add engine
oil of the same type as that
already in the engine.
Make sure to check the oil type and prepare the items needed
before adding oil.
Remove the oil filler cap by turning it counterclockwise.
Add engine oil slowly, checking the dipstick.
Install the oil filler cap by turning it clockwise.
■ Engine oil consumption
A certain amount of engine oil will be consumed while driving. In the following
situations, oil consumption may increase, and engine oil may need to be
refilled in between oil maintenance intervals.
● When the engine is new, for example directly after purchasing the vehicle or
after replacing the engine
● If low quality oil or oil of an inappropriate viscosity is used
● When driving at high engine speeds or with a heavy load, or when driving
while accelerating or decelerating frequently
● When leaving the engine idling for a long time, or when driving frequently
through heavy traffic
Engine oil selection P. 773
Oil quantity (Low  Full)1.5 L (1.6 qt., 1.3 lmp. qt.)
ItemsClean funnel
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6407-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
■Used engine oil
● Used engine oil contains potentially harmful contaminants which may
cause skin disorders such as inflammation and skin cancer, so care
should be taken to avoid prolonged and repeated contact. To remove used
engine oil from your skin, wash thoroughly with soap and water.
● Dispose of used oil and filters only in a safe and acceptable manner. Do
not dispose of used oil and filters in household trash, in sewers or onto the
ground. Call any authorized Toyota reta iler or Toyota authorized repairer,
or any reliable repairer, service station or auto parts store for information
concerning recycling or disposal.
● Do not leave used engine oil within the reach of children.
NOTICE
■To prevent serious engine damage
Check the oil level on a regular basis.
■ When replacing the engine oil
● Be careful not to spill engine oil on the vehicle components.
● Avoid overfilling, or the engine could be damaged.
● Check the oil level on the dipstick every time you refill the vehicle.
● Be sure the engine oil filler cap is properly tightened.

6417-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
The coolant level is satisfactory if it is between the “MAX” and “MIN”
lines on the reservoir when the hybrid system is cold.
■Engine coolant reservoir
Reservoir cap
“MAX” line
“MIN” line
If the level is on or below the
“MIN” line, add coolant up to the
“MAX” line. ( P. 761)
■Power control unit coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to
the “FULL” line. ( P. 761)
Coolant
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6427-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene
glycol based non-silicate, non-amine, non- nitrite, and non-borate coolant with
long-life hybrid organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -35 C [-31F])
For more details about coolant, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have any authorized Toyota retailer or Toyota autho-
rized repairer, or any reliable repairer, test the cap and check for leaks in the
cooling system.
WARNING
■ When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps.
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
■ When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of
water and antifreeze must be used to provide proper lubrication, corrosion
protection and cooling. Be sure to read the antifreeze or coolant label.
■ If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.

6437-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of
their condition, have your vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
Radiator and condenser
WARNING
■ When the hybrid system is hot
Do not touch the radiator or condenser as they may be hot and cause seri-
ous injuries, such as burns.
■ When the electric cooling fans are operating
Do not touch the engine compartment.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. Be sure the power switch is off when working near the electric cool-
ing fans or radiator grille.

6447-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Check the 12-volt battery as follows.
■12-volt battery exterior
Make sure that the 12-volt battery terminals are not corroded and
that there are no loose connections, cracks, or loose clamps.
Terminals
■Checking battery fluid
Check that the level is between the upper and lower lines.
Upper line
Lower line
If the fluid level is at or below
the lower line, add distilled
water.
■Adding distilled water
Remove the vent plug.
Add distilled water.
If the upper line cannot be seen,
check the fluid level by looking
directly at the cell.
Put the vent plug back on and close it securely.
12-volt battery
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LOWO.K.2
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6457-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
■ When opening the cover of the positive (+) battery terminal
■ Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flam-
mable and explosive. Therefore, obser ve the following precautions before
recharging:
● If recharging with the 12-volt battery installed on the vehicle, be sure to dis-
connect the ground cable.
● Make sure the power switch on the charger is off when connecting and dis-
connecting the charger cables to the 12-volt battery.
■ After recharging/reconnecting the 12-volt battery
● Unlocking the doors using the smart entry & start system may not be possi-
ble immediately after reconnecting the 12-volt battery. If this happens, use
the wireless remote control or the mechanical key to lock/unlock the doors.
● Start the hybrid system with the power switch in ACCESSORY mode. The
hybrid system may not start with the power switch turned off. However, the
hybrid system will operate normally from the second attempt.
● The power switch mode is recorded by the vehicle. If the 12-volt battery is
reconnected, the vehicle will return the power switch mode to the status it
was in before the 12-volt battery was disconnected. Make sure to turn off
the power before disconnect the 12-volt battery. Take extra care when con-
necting the 12-volt battery if the power switch mode prior to discharge is
unknown.
If the system will not start even after multiple attempts at all methods above,
contact any authorized Toyota retailer or Toyota authorized repairer, or any
reliable repairer.
While pushing the portion shown in the
illustration from both sides, lift the end of
the cover up.

6467-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may
produce hydrogen gas which is flammable and explosive. To reduce the risk
of death or serious injury, take the following precautions while working on or
near the 12-volt battery:
● Do not cause sparks by touching the 12-volt battery terminals with tools.
● Do not smoke or light a match near the 12-volt battery.
● Avoid contact with eyes, skin and clothes.
● Never inhale or swallow electrolyte.
● Wear protective safety glasses when working near the 12-volt battery.
● Keep children away from the 12-volt battery.
■ Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charge the 12-
volt battery in a garage or closed room where there is insufficient ventila-
tion.
■ Emergency measures regarding electrolyte
● If electrolyte gets in your eyes
Flush your eyes with clean water for at least 15 minutes and get immedi-
ate medical attention. If possible, continue to apply water with a sponge or
cloth while traveling to the nearest medical facility.
● If electrolyte gets on your skin
Wash the affected area thoroughly. If you feel pain or burning, get medical
attention immediately.
● If electrolyte gets on your clothes
It can soak through clothing on to your skin. Immediately take off the cloth-
ing and follow the procedure above if necessary.
● If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergency medical attention
immediately.

6477-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
WARNING
■ When disconnecting the 12-volt battery
Do not disconnect the negative (-) terminal on the body side. The discon-
nected negative (-) terminal may touch the positive (+) terminal, which may
cause a short and result in death or serious injury.
NOTICE
■ When recharging the 12-volt battery
Never recharge the 12-volt battery while the hybrid system is operating.
Also, be sure all accessories are turned off.
■ When adding distilled water
Avoid overfilling. Water spilled during 12-volt battery recharging may cause
corrosion.