2020 TOYOTA PRIUS PLUG-IN HYBRID coolant temperature

2153. Instrument cluster
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Instrument cluster
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Warning lights inform the driver of malfunctions in any of the vehicle’s
systems.
Warning lights
Warning lightsPages
*1Brake system warning light (Red) P. 714
*1Brake system warning light (Yellow) P. 714
*1Charging system warning light P. 714
*1Low engine oil pressure warning light P. 715
*1Malfunction indicator lamp P. 715
*1SRS warning light P. 715
*1ABS warning light P. 715
*1Electric power steering system warning light
(Red/yellow) P. 715
*1, 2PCS warning light P. 716
LTA indicator (Orange) P. 716
*1Slip indicator light P. 716
*1High coolant temperature warning light P. 716
*1, 3PKSB OFF indicator (if equipped) P. 717
Open door warning light P. 717

2213. Instrument cluster
3
Instrument cluster
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
■If a safety system warning light does not come on
Should a safety system light such as the ABS and SRS warning light 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 any authorized
Toyota retailer or Toyota authorized repairer, or any reliable repairer imme-
diately 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 vehicle in a
safe place, and check the engine after it has cooled completely. ( P. 761)

5796-1. Using the air conditioning system and defogger
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Interior features
■ Heating
● In HV mode, the gasoline engine may operate in order to extract heat from
the engine coolant via the heater.
● In EV mode, heating is done by a heat pump system.
• When the outside temperature is low or it is snowing, compared to con-
ventional vehicles, heating may be less effective and warm air may not
come out.
• If frost has formed on the outside heat exchanger, the heating perfor-
mance will decline. The frost can be removed from the outside heat
exchanger by operating the Remote Ai r Conditioning System before driv-
ing ( P. 585). When frosted over, the heating operation of the Remote
Air Conditioning System starts after defrosting.
• When is turned on, the heating is controlled optimally. Therefore,
the set heating performance may not be achieved even if the fan speed
setting is increased.
● In the following situations the gasoline engine may operate in order to
extract heat from the engine coolant via the heater even in EV mode.
• The outside temperature is approx imately -10°C (14°F) or low
• is operating
■ Using automatic mode
Fan speed is adjusted automatically according to the temperature setting and
the ambient conditions.
Therefore, the fan may stop for a while until warm or cool air is ready to flow
immediately after is pressed.
• When the outside heat exchanger is
frosted over, fan speed declines and it
may become harder to heat the inte-
rior. However, it is not a malfunction.
In this situation, the air temperature
from the outlets may not change even
though the set temperature is raised.Outside heat exchanger

6297-2. Maintenance
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Maintenance and care
■Where to go for maintenance service?
In order to maintain your vehicle in the best possible condition, Toyota recom-
mends that maintenance service operations as well as other inspections and
repairs be carried out by authorized Toyota retailers or Toyota authorized
repairers, or any reliable repairers. For repairs and services covered by your
warranty, please visit an authorized Toyota retailer or repairer, who will use
genuine Toyota parts in repairing any difficulties you may encounter. There
can also be advantages in utilizing authorized Toyota retailers or repairers for
non-warranty repairs and services, as members of the Toyota network will be
able to expertly assist you with any difficulties you may encounter.
Your Toyota retailer or Toyota authorized repairer, or any reliable repairer will
perform all of the scheduled maintenance on your vehicle reliably and eco-
nomically due to their experience with Toyota vehicles.
■Does your vehicle need repairs?
Be on the alert for changes in performance and sounds, and visual tip-offs
that indicate service is needed. Some important clues are:
●Engine missing, stumbling or pinging
●Appreciable loss of power
●Strange engine noises
●A fluid leak under the vehicle (However, water dripping from the air condi-
tioning system after use is normal.)
●Change in exhaust sound (This may indicate a dangerous carbon monoxide
leak. Drive with the windows open and have the exhaust system checked
immediately.)
●Flat-looking tires, excessive tire squeal when cornering, uneven tire wear
●Vehicle pulls to one side when driven straight on a level road
●Strange noises related to suspension movement
●Loss of brake effectiveness, spongy feeling brake pedal, pedal almost
touches the floor, vehicle pulls to one side when braking
●Engine coolant temperature continually higher than normal (P. 716, 761)
If you notice any of these clues, take your vehicle to any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer as soon as pos-
sible. Your vehicle may need adjustment or repair.

6327-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
The engine compartment contains many mechanisms and fluids that may
move suddenly, become hot, or become el ectrically energized. To avoid death
or serious injury, observe the following precautions.
■ When working on the engine compartment
● Make sure that the “Accessory”, “Ignition ON” or mileage display (P. 223)
on the main display and the “READY” indicator are both off.
● Keep hands, clothing and tools away from the moving fan.
● Be careful not to touch the engine, power control unit, radiator, exhaust
manifold, etc. right after driving as they may be hot. Oil and other fluids
may also be hot.
● Do not leave anything that may burn easily, such as paper and rags, in the
engine compartment.
● Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes
are flammable.
● Be extremely cautious when working on the 12-volt battery. It contains poi-
sonous and corrosive sulfuric acid.
● Take care because brake fluid can harm your hands or eyes and damage
painted surfaces. If fluid gets on your hands or in your eyes, flush the
affected area with clean water immediately. If you still experience discom-
fort, consult a doctor.
■ When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
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. ( P. 643)
■ Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc.
from getting in your eyes.

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
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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.

7138-2. Steps to take in an emergency
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When trouble arises
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