engine coolant TOYOTA PRIUS PLUG-IN HYBRID 2021 User Guide

6437-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
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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
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
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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

7168-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
(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. 416, 723)
If the PCS (Pre-Collision System) or VSC (Vehicle Stability
Control) system is disabled, the PCS warning light will illu-
minate.
 P. 428
(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. 444)
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. 761)
• 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

7648-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(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. 223) 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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7658-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(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.

7769-1. Specifications
Prius Plug-in Hybrid_OM_OM47D72E_(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.

801Alphabetical index
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Child-protectors ....................... 286
Cleaning............................ 616, 622
Aluminum wheels .................. 617
Exterior.................................. 616
Front camera......................... 408
Hybrid battery (traction
battery) air intake vent ........ 623
Interior ................................... 622
Radar sensor ........................ 407
Seat belts .............................. 625
Water-repellent coating ......... 617
Clock ......................................... 204
Adjustment ............................ 210
Coat hooks ............................... 613
Combination meter .................. 204
Clock adjustment .................. 210
Main display .......................... 222
Multi-information display ....... 230
Warning lights and
indicators ............................ 214
Condenser ................................ 643
Console box ............................. 595
Consumption screen ............... 275
Coolant ..................................... 641
Capacity ................................ 776
Checking ............................... 641
Preparing and checking
before winter....................... 566
Cooling system ........................ 641
Engine overheating ............... 761
Hybrid system overheating ... 763
Cruise control
Dynamic radar cruise control
with full-speed range .......... 451
Cup holders .............................. 596
Curtain shield airbags ............... 39
Customizable features ............ 782Daytime running light
system .................................... 388
Deck board ............................... 600
Defogger
Outside rear view mirrors...... 577
Rear window ......................... 577
Windshield ............................ 577
Dimension ................................ 770
Display
Drive information................... 232
Dynamic radar cruise control
with full-speed range .......... 451
Energy monitor ............. 233, 272
Head-up display .................... 264
LTA (Lane Tracing Assist) .... 438
Main display .......................... 222
Multi-information display ....... 230
Parking Support Brake
function ............................... 516
Pre-collision warning............. 419
RCTA detection screen......... 473
RSA (Road Sign Assist)........ 446
S-IPA (Simple Intelligent
Parking Assist System) ...... 527
Toyota parking assist
sensor................................. 500
Warning messages ............... 723
Do-it-yourself maintenance .... 631
Door courtesy lights................ 591
Location ................................ 591
Wattage ................................ 779D

803Alphabetical index
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Emergency brake signal ......... 560
Emergency flashers................. 704
Emergency brake signal ....... 560
Emergency tire puncture
repair kit ................................. 731
Energy monitor ................ 233, 272
Engine
Accessory mode ................... 375
Compartment ........................ 637
Engine switch ........................ 373
Exhaust gas precautions......... 50
Hood ..................................... 634
How to start the hybrid
system ................................ 373
Identification number............. 772
If the hybrid system will not
start..................................... 749
If your vehicle has to be
stopped in an emergency ... 705
Ignition switch (power
switch) ................................ 373
Overheating .......................... 761
Power switch ......................... 373
Engine coolant ......................... 641
Capacity ................................ 776
Checking ............................... 641
Preparing and checking
before winter....................... 566Engine oil ................................. 638
Capacity ................................ 773
Checking ............................... 638
Oil pressure warning light ..... 715
Preparing and checking
before winter....................... 566
Engine switch (power
switch) .................................... 373
Auto power off function ......... 375
Changing the power switch
modes................................. 375
If your vehicle has to be
stopped in an emergency ... 705
Starting the hybrid system .... 373
EPS (Electronic Power
Steering)................................. 560
Function ................................ 560
Warning light ......................... 715
EV City mode switch ................. 98
EV driving range ...................... 119
EV mode ..................................... 95
EV/HV mode selection
switch ....................................... 98
Exhaust gas precautions .......... 50

808Alphabetical index
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Navigation system*
Odometer .................................. 224
Oil
Engine oil .............................. 773
Opener
Back door .............................. 288
Fuel filler door ....................... 403
Hood ..................................... 634
Outside rear view mirrors ....... 350
Adjustment ............................ 350
BSM (Blind Spot Monitor) ..... 473
Folding .................................. 350
Outside rear view mirror
defoggers............................ 577
Outside temperature
display .................................... 222
Overhead console.................... 598
Overheating .............................. 761
P position switch ..................... 380
Panoramic view monitor
*
Parking assist sensors
Parking Support Brake
function ............................... 510
S-IPA (Simple Intelligent
Parking Assist System)....... 523
Toyota parking
assist-sensor ...................... 499Parking brake ........................... 386
Operation .............................. 386
Parking brake engaged
warning buzzer ................... 386
Parking lock ............................. 380
Parking Support Brake
function .................................. 510
PCS (Pre-Collision System) .... 418
Enabling/disabling the
system ................................ 422
Function ................................ 418
Warning light ......................... 716
Personal lights ......................... 591
Switch ................................... 592
Wattage ................................ 779
Plug-in hybrid system ............... 94
Driving tips ............................ 115
EV City mode .......................... 95
EV driving range ................... 119
EV mode ................................. 95
EV/HV mode selection
switch ................................... 98
Features.................................. 94
How to charge....................... 165
HV mode ................................. 95
Hybrid battery (traction
battery) charge mode ........... 95
Power control unit coolant ..... 641
Capacity ................................ 776
Checking ............................... 641
Preparing and checking
before winter....................... 566
Radiator ................................ 643
N
O
P

814Alphabetical index
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Warning lights .......................... 215
ABS ....................................... 715
Brake Override System ......... 719
Brake system ........................ 714
Charging system ................... 714
Drive-Start Control ................ 719
Driver’s seat belt reminder
light ..................................... 717
Electronic engine control
system ................................ 715
Electric power steering
system ................................ 715
Front passenger’s seat belt
reminder light...................... 717
High coolant temperature...... 716
Low engine oil pressure ........ 715
Low fuel level ........................ 717
Malfunction indicator lamp .... 715
Master warning light .............. 717
Open door ............................. 717
Parking Support Brake
function ............................... 719
PCS....................................... 716
PKSB OFF indicator.............. 717
Rear passengers’ seat belt
reminder light...................... 717
Seat belt reminder light ......... 717
Slip indicator ......................... 716
SRS....................................... 715
Tire pressure ......................... 718
Warning messages .................. 723Warning reflector storage
space ...................................... 602
Washer...................................... 398
Checking ............................... 648
Preparing and checking
before winter....................... 566
Switch ................................... 398
Washing and waxing ............... 616
Water-repellent coating........... 617
Wheels ...................................... 667
Replacing wheels.................. 669
Size ....................................... 779
Window glasses....................... 352
Window lock switch ................ 352
Windows ................................... 352
Power windows ..................... 352
Rear window defogger .......... 577
Washer ................................. 398
Windshield wipers ................... 398
Handling the wiper arms ....... 621
Rain-sensing windshield
wipers ................................. 398
Replacing the wiper insert .... 685
Winter driving tips ................... 566
Wiper insert replacement........ 685
Wireless charger...................... 607
Wireless remote control.......... 278
Battery-Saving Function ....... 295
Locking/Unlocking................. 283
Remote Air Conditioning
System ............................... 585
Replacing the battery ............ 688