2021 TOYOTA PRIUS PLUG-IN HYBRID coolant temperature

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

7618-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
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. 716) comes on
or flashes, or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
● “Hybrid System Overheated” is shown on the multi-information
display.
● Steam comes out from under the hood.
Correction procedures
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7628-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
The coolant level is satisfactory if it is between the “MAX” and
“MIN” lines on the reservoir.
Reservoir
“MAX” line
“MIN” 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 temperature setting is adjusted to “LO” and
“A/C” switch ( ) is turned on immediately after a cold start. Con-
firm that the fans are operating by checking the fan sound and air flow. If
it is difficult to check these, turn the “A/C” switch ( ) 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.
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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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804Alphabetical index
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
Flat tire ...................................... 731
Floor mats .................................. 30
Fluid
Brake..................................... 778
Transmission......................... 777
Washer.................................. 648
Fog lights.................................. 397
Replacing light bulbs ............. 700
Switch ................................... 397
Follow me home system ......... 388
Footwell lights.......................... 591
Front doors............................... 283
Front fog lights ........................ 397
Replacing light bulbs ............. 700
Switch ................................... 397
Front passenger’s seat belt
reminder light ........................ 717
Front position lights ................ 387
Light switch ........................... 387
Replacing light bulbs ............. 700
Front seat concentrated
airflow mode (S-FLOW)......... 575
Front seats ............................... 339
Adjustment ............................ 339
Cleaning ................................ 622
Correct driving posture............ 32
Head restraints...................... 343
Seat heaters.......................... 589
Front turn signal lights............ 385
Replacing light bulbs ............. 700
Turn signal lever ................... 385
Fuel ........................................... 401
Capacity ................................ 772
Fuel gauge ............................ 222
Information ............................ 780
Refueling ............................... 401
Type ...................................... 772
Warning light ......................... 717
Fuel consumption ............ 244, 275
Average fuel consumption .... 244
Current fuel consumption ...... 275Fuel filler door.......................... 403
Opener .................................. 403
Refueling............................... 401
When the fuel filler door
cannot be opened............... 403
Fuses ........................................ 691
Glove box ................................. 595
Hands-free system (for
cellular phone)
*
Head restraints ........................ 343
Head-up display ....................... 264
Headlights ................................ 387
AHS (Adaptive High-beam
System) .............................. 391
Automatic headlight
leveling ............................... 389
Follow me home system ....... 388
Light switch ........................... 387
Replacing light bulbs............. 700
Heaters
Automatic air conditioning
system ................................ 572
Hybrid battery (traction
battery) ............................... 154
Outside rear view mirrors...... 577
Seat heaters ......................... 589
High coolant temperature
warning light .......................... 716
High mounted stoplight
Replacing .............................. 700
High-voltage components ...... 108
Hill-start assist control............ 559
Hood ......................................... 634
Hooks
Coat hooks............................ 613
Grocery bag hook ................. 601
Retaining hooks (floor mat)..... 30
F
G
H

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