Page 386 of 568

3866-3. Do-it-yourself maintenance
PRIUS +_OM_OM47D30E_(EE)
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.
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.
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.
Page 443 of 568

4437-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
7
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
Page 449 of 568

4497-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
7
When trouble arises
(If equipped)
Hybrid system overheat warning light (warning buzzer)
Indicates that the hybrid system has overheated
This light may come on when driving under severe operat-
ing conditions, and the output of the hybrid system may
temporarily decrease in order to protect the system. (For
example, when driving up a long steep hill or driving up a
steep hill in reverse.)
Stop the vehicle in a safe place.
Handling method ( P. 520)
(If equipped)
Cruise control indicator (yellow indicator)
Indicates a malfunction in the cruise control
Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable
repairer immediately.
(Only outer frame flashes)(If equipped)
Low hybrid battery (traction battery) warning light
(warning buzzer)
Hybrid battery (traction battery) level becomes low
because the shift position is in N for long time
Because recharging is not possible when the shift
position is in N, shift the shift position to P when
parking the vehicle for a long time.
High coolant temperature warning light
Changes from a flashing to a solid light when the engine
coolant temperature increases
Immediately stop the vehicle in a safe place.
( P. 518)
Automatic headlight leveling system warning light
Indicates a malfunction in the automatic headlight leveling
system
Have the vehicle inspected by any authorized Toyota
retailer or Toyota authorized repairer, or any reliable
repairer immediately.
Open door warning light (warning buzzer)*3
Indicates that a door is not fully closed
Check that all the doors are closed.
Low fuel level warning light
Indicates that remaining fuel is approximately 6.0 L (1.6
gal., 1.3 Imp.gal.) or less
Refuel the vehicle.
Warning lightWarning light/Details/Actions
Page 518 of 568

5187-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
If your vehicle overheats
■If the high coolant temperature warning light comes on or
flashes
Stop the vehicle in a safe place and turn off the air conditioning
system, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has cooled down sufficiently, inspect the
hoses and radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
any authorized Toyota retailer
or Toyota authorized repairer,
or any reliable repairer.
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light (P. 449) comes on
or flashes, or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
● Vehicles without multi-information display: The hybrid system
overheat warning light ( P. 449) comes on.
● Vehicles with multi-information display: The warning message
indicating overheat is shown on the multi-information display.
( P. 464)
● Steam comes out from under the hood.
Correction procedures
1
2
3
1
2
Page 519 of 568

5197-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
7
When trouble arises
The coolant level is satisfactory if it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the hybrid system and turn the air conditioning system on to
check that the radiator cooling fans operate and to check for
coolant leaks from the radiator or hoses.
The fans operate when the air condi tioning system is turned on immedi-
ately after a cold start. Confirm that the fans are operating by checking
the fan sound and air flow. If it is difficult to check these, turn the air con-
ditioning system on and off repeatedly. (The fans may not operate in
freezing temperatures.)
If the fans are not operating:
Stop the hybrid system immediately and contact any authorized
Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
If the fans are operating:
Have the vehicle inspected at the nearest any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
4
1
2
3
5
6
7
Page 520 of 568
5207-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
■If the hybrid system overheat warning light comes on or the
warning message indicating overheat is shown on the multi-
information display
Stop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
After the hybrid system has cooled down, inspect the hoses and
radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
any authorized Toyota retailer
or Toyota authorized repairer,
or any reliable repairer.
The coolant level is satisfactory if it is between the “F” and “L”
lines on the reservoir.
Reservoir
“F” line
“L” line
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
If water was added in an emer-
gency, have the vehicle
inspected at any authorized
Toyota retailer or Toyota autho-
rized repairer, or any reliable
repairer as soon as possible.
1
2
3
1
2
4
1
2
3
5
Page 521 of 568

5217-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
7
When trouble arises
After stopping the hybrid system and waiting for 5 minutes or
more, start the hybrid system and check for the instrument clus-
ter or multi-information display.
If the hybrid system overheat warning light does not turn off or
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 hybrid system overheat warning light does not come on or
the message is not displayed:
The hybrid system temperature has dropped and the vehicle may
be driven normally.
However, if the warning light comes on again frequently or the message
appears again frequently, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
WARNING
■ 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 indicator on the
power switch and the “READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automati-
cally start, or the cooling fan 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 cap while the hybrid system and radia-
tor are hot.
High temperature steam or coolant could spray out.
6
Page 522 of 568
5227-2. Steps to take in an emergency
PRIUS +_OM_OM47D30E_(EE)
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.