2023 TOYOTA PRIUS PLUG-IN HYBRID engine coolant

5917-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47F38E_(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. 705)
■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. 705)
Coolant
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5927-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47F38E_(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.

5937-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47F38E_(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.

6588-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
If you think something is wrong
●Fluid leaks under the vehicle
(Water dripping from the air conditioning after use is normal.)
● Flat-looking tires or uneven tire wear
● High coolant temperature warning light flashes or comes on
● Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the hybrid system
● Engine missing, stumbling or running roughly
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road
● Loss of brake effectiveness, spongy feeling, pedal almost touches
the floor
If you notice any of the following symptoms, your vehicle proba-
bly needs adjustment or repair. Contact any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer as
soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

6618-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
8
When trouble arises
(Flashes or illuminates)
PCS warning light
• When a buzzer sounds simultaneously:
Indicates a malfunction has occurred in the PCS (Pre-
Collision System).
 Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable
repairer immediately.
• When a buzzer does not sound:
The PCS (Pre-Collision System) has become temporar-
ily unavailable, corrective action may be necessary.
 Follow the instructions displayed on the multi-infor-
mation display. ( P. 366, 667)
If the PCS (Pre-Collision System) or VSC (Vehicle Stability
Control) system is disabled, the PCS warning light will illu-
minate.
 P. 378
(Orange)
LTA indicator (warning buzzer)
Indicates a malfunction in the LTA (Lane Tracing Assist)
 Follow the instructions displayed on the multi-infor-
mation display. ( P. 394)
Slip indicator light
Indicates a malfunction in:
• The VSC system;
• The TRC system; or
• The hill-start assist control system
 Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable
repairer immediately.
The light will flash when the ABS, VSC or TRC system is
operating.
High coolant temperature warning light
• When the light flashes:
Indicates that the engine coolant temperature is too high
The light changes from a flashing to a solid light when
the temperature further increases
 Immediately stop the vehicle in a safe place.
( P. 705)
• When the light comes on without flashing:
Indicates a malfunction in the exhaust heat recirculator
system
 Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable
repairer immediately.
Warning lightWarning light/Details/Actions

7088-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
After stopping the hybrid system and waiting for 5 minutes or
more, start the hybrid system again and check if “Hybrid System
Overheated” is shown on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
If the message is not displayed:
The hybrid system temperature has dropped and the vehicle may
be driven normally.
However, if the message appears again frequently, contact any autho-
rized Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
WARNING
■ To prevent an accident or injury when inspecting under the hood of
your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
● If steam is seen coming from under the hood, do not open the hood until
the steam has subsided. The engine compartment may be very hot.
● After the hybrid system has been turned off, check that the “Accessory”,
“Ignition ON” or mileage display ( P. 213) on the main display and the
“READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automati-
cally start, or the cooling fans may suddenly operate even if the gasoline
engine stops. Do not touch or approach rotating parts such as the fan,
which may lead to fingers or clothing (especially a tie, a scarf or a muffler)
getting caught, resulting in serious injury.
● Do not loosen the coolant reservoir caps while the hybrid system and radi-
ator are hot.
High temperature steam or coolant could spray out.
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7098-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
8
When trouble arises
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently.
Adding cool coolant to a hot hybrid system too quickly can cause damage to
the hybrid system.
■ To prevent damage to the cooling system
Observe the following precautions:
● Avoid contaminating the coolant with foreign matter (such as sand or dust
etc.).
● Do not use any coolant additive.

7209-1. Specifications
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
*: The fluid capacity is the quantity of reference.
If replacement is necessary, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
Cooling system
Capacity*
Gasoline
engine6.2 L (6.6 qt., 5.5 Imp.qt.)
Power
control unit1.5 L (1.6 qt., 1.3 Imp.qt.)
Coolant type
Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based
non-silicate, non-amine, non-nitrite, and
non-borate coolant with long-life hybrid
organic acid technology
Do not use plain water alone.
Ignition system (spark plug)
MakeDENSO FC16HR-CY9
Gap0.9 mm (0.035 in.)
NOTICE
■ Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.