2023 TOYOTA PRIUS PLUG-IN HYBRID coolant temperature

6618-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
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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

7058-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(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. 661) 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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7068-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47F38E_(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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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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748Alphabetical index
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
Flat tire ...................................... 675
Floor mats .................................. 30
Fluid
Brake..................................... 722
Transmission......................... 721
Washer.................................. 598
Fog lights.................................. 347
Replacing light bulbs ............. 644
Switch ................................... 347
Footwell lights.......................... 541
Front doors............................... 273
Front fog lights ........................ 347
Replacing light bulbs ............. 644
Switch ................................... 347
Front passenger’s seat belt
reminder light ........................ 662
Front position lights ................ 337
Light switch ........................... 337
Replacing light bulbs ............. 644
Front seat concentrated
airflow mode (S-FLOW)......... 525
Front seats ............................... 290
Adjustment ............................ 290
Cleaning ................................ 572
Correct driving posture............ 32
Head restraints...................... 294
Seat heaters.......................... 539
Front turn signal lights............ 335
Replacing light bulbs ............. 644
Turn signal lever ................... 335
Fuel ........................................... 351
Capacity ................................ 716
Fuel gauge ............................ 212
Information ............................ 724
Refueling ............................... 351
Type ...................................... 716
Warning light ......................... 662
Fuel consumption ............ 234, 264
Average fuel consumption .... 234
Current fuel consumption ...... 264Fuel filler door.......................... 353
Opener .................................. 353
Refueling............................... 351
When the fuel filler door
cannot be opened............... 353
Fuses ........................................ 635
Glove box ................................. 545
Hands-free system (for
cellular phone)
*
Head restraints ........................ 294
Head-up display ....................... 254
Headlights ................................ 337
AHS (Adaptive High-beam
System) .............................. 341
Automatic headlight
leveling ............................... 339
Extended Headlight
Lighting system .................. 338
Light switch ........................... 337
Replacing light bulbs............. 644
Heaters
Automatic air conditioning
system ................................ 522
Hybrid battery (traction
battery) ............................... 144
Outside rear view mirrors...... 527
Seat heaters ......................... 539
High coolant temperature
warning light .......................... 661
High mounted stoplight
Replacing .............................. 644
High-voltage components ........ 98
Hill-start assist control............ 509
Hood ......................................... 584
F
G
H

752Alphabetical index
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
Navigation system*
Odometer .................................. 214
Oil
Engine oil .............................. 717
Opener
Back door .............................. 278
Fuel filler door ....................... 353
Hood ..................................... 584
Outside rear view mirrors ....... 301
Adjustment ............................ 301
BSM (Blind Spot Monitor) ..... 423
Folding .................................. 301
Outside rear view mirror
defoggers............................ 527
Outside temperature
display .................................... 212
Overhead console.................... 548
Overheating .............................. 705
P position switch ..................... 330
Panoramic view monitor
*
Parking assist sensors
Parking Support Brake
function ............................... 462
S-IPA (Simple Intelligent
Parking Assist System)....... 473
Toyota parking
assist-sensor ...................... 450Parking brake ........................... 336
Operation .............................. 336
Parking brake engaged
warning buzzer ................... 336
Parking lock ............................. 330
Parking Support Brake
function .................................. 462
PCS (Pre-Collision System) .... 368
Enabling/disabling the
system ................................ 372
Function ................................ 368
Warning light ......................... 661
Personal lights ......................... 541
Switch ................................... 542
Wattage ................................ 723
Plug-in hybrid system ............... 84
Driving tips ............................ 105
EV City mode .......................... 85
EV driving range ................... 109
EV mode ................................. 85
EV/HV mode selection
switch ................................... 88
Features.................................. 84
How to charge....................... 155
HV mode ................................. 85
Hybrid battery (traction
battery) charge mode ........... 85
Power control unit coolant ..... 591
Capacity ................................ 720
Checking ............................... 591
Preparing and checking
before winter....................... 516
Radiator ................................ 593
N
O
P

758Alphabetical index
Prius Plug-in Hybrid_OM_OM47F38E_(EE)
Warning lights .......................... 205
ABS ....................................... 660
Brake Override System ......... 663
Brake system ........................ 659
Charging system ................... 659
Drive-Start Control ................ 663
Driver’s seat belt reminder
light ..................................... 662
Electronic engine control
system ................................ 660
Electric power steering
system ................................ 660
Front passenger’s seat belt
reminder light...................... 662
High coolant temperature...... 661
Low engine oil pressure ........ 660
Low fuel level ........................ 662
Malfunction indicator lamp .... 660
Master warning light .............. 662
Open door ............................. 662
Parking Support Brake
function ............................... 663
PCS....................................... 661
PKSB OFF indicator.............. 662
Rear passengers’ seat belt
reminder light...................... 662
Seat belt reminder light ......... 662
Slip indicator ......................... 661
SRS....................................... 660
Tire pressure ......................... 663
Warning messages .................. 667Warning reflector storage
space ...................................... 552
Washer...................................... 348
Checking ............................... 598
Preparing and checking
before winter....................... 516
Switch ................................... 348
Washing and waxing ............... 566
Water-repellent coating........... 567
Wheels ...................................... 610
Replacing wheels.................. 612
Size ....................................... 723
Window glasses....................... 303
Window lock switch ................ 303
Windows ................................... 303
Power windows ..................... 303
Rear window defogger .......... 527
Washer ................................. 348
Windshield wipers ................... 348
Handling the wiper arms ....... 571
Rain-sensing windshield
wipers ................................. 348
Replacing the wiper insert .... 629
Winter driving tips ................... 516
Wiper insert replacement........ 629
Wireless charger...................... 557
Wireless remote control.......... 268
Battery-Saving Function ....... 285
Locking/Unlocking................. 273
Remote Air Conditioning
System ............................... 535
Replacing the battery ............ 632