2012 TOYOTA PRIUS coolant temperature

218 2-2. Instrument cluster
CAUTION
■To prevent an accident
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. 549)
Do not place anything or attach a sticker
in front of the instrument cluster. The item
may obscure or obstruct the display, or
could reflect off the display, possibly
causing an accident.Instrument cluster

425
4-3. Do-it-yourself maintenance
4
Maintenance and care
■
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.
U.S.A.: “Toyota Super Long Life Coolant” is a mixture of 50% cool- ant and 50% deionized water. (Minimum temperature: -31 F
[-35 C])
Canada: “Toyota Super Long Life Coolant” is a mixture of 55% cool- ant and 45% deionized water. (Minimum temperature: -44 F
[-42 C])
For more details about coolant, contact your Toyota dealer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reser-
voir caps, drain cock and water pump.
If you cannot find a leak, have your Toyota dealer test the cap and check for
leaks in the cooling system.
CAUTION
■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.

494 5-2. Steps to take in an emergency
Stop the vehicle immediately.The following warning indicates the possibility of damage to the vehi-
cle that may lead to an accident. Immediately stop the vehicle in a
safe place and contact your Toyota dealer.
Warning lightWarning light/Details
Charging system warning light Indicates a malfunction in the vehicle’s charging system
High coolant temperature warning light Indicates that the coolant temperature is too high
Changes from a flashing to a solid light when the engine
coolant temperature increases.

5
When trouble arises
549
5-2. Steps to take in an emergency
If your vehicle overheats
Correction procedures■ If the high coolant temperature warning light flashes or comes
on
Stop the vehicle in a safe place and turn off the air condition-
ing system.
Check to see if steam is coming out from under the hood.
If you see steam: Stop the hybrid system. Carefully lift the hood after the
steam subsides and then restart the hybrid system.
If you do not see steam: Leave the hybrid system operating and carefully lift the
hood.
The following may indicate that your vehicle is overheating:
●The high coolant temperature warn ing light flashes or comes on:
The engine may be overheating.
● “HYBRID SYSTEM OVERHEAT” is shown on the multi-informa-
tion display:
The power control unit may be overheating.
Follow the correction procedure as described below.
STEP 1
STEP 2

550 5-2. Steps to take in an emergency
Check to see if the cooling fans are operating.
If the fans are operating: Wait until the high coolant temperature warning light goes
off and then stop the hybrid system.
If the fans are not operating: Stop the hybrid system immediately and call your Toyota
dealer.
After the hybrid system has
cooled down sufficiently, check
the engine coolant level and
inspect the cooling system for
leaks.
If necessary, add engine coolant
up to the “FULL” line.
Water can be used in an emer-
gency measure if engine coolant
is unavailable. (P. 566)
Have the vehicle checked at nearest Toyota dealer as soon as possi-
ble.
STEP 3
STEP 4
ITO52P130
STEP 5

627
Alphabetical index
Tonneau cover......................... 377
Tools......................................... 523
Touch tracer display ............... 215
Total load capacity .................. 316
Towing
Dinghy towing ....................... 323
Emergency towing ................ 486
Trailer towing ........................ 322
TRAC ........................................ 296
Traction control ....................... 296
Trailer towing........................... 322
Transmission Hybrid transmission .............. 202
P position switch................... 205
Trip information....................... 229
Trip meter................................. 214
Turn signal lights Replacing light bulbs ............ 467
Switch ................................... 211
Wattage ................................ 570
USB port
*................................ 352
Vanity lights Vanity lights .......................... 365
Wattage ................................ 570
Vanity mirrors .......................... 365
Vehicle control and operation
data recording ......................... 24
Vehicle identification
number................................... 561
Vehicle proximity notification system ..................................... 32
Vehicle stability control .......... 296
VSC ........................................... 296 Warning buzzers
Brake system ........................493
Open door ............................498
Seat belt reminder .................498
Warning lights
Anti-lock brake system (ABS) ..................................495
Automatic headlight leveling
system ................................497
Brake system ................493, 496
Charging system .... ...............494
Cruise control ........................497
Electric power steering system ................................495
High coolant temperature ......494
Hybrid system .......................495
Low fuel level ........................498
Low tire pressure...................499
Malfunction indicator lamp ....495
Open door .............................498
Pre-collision system ..............496
Radar cruise control. .............497
Seat belt warning light ...........498
Slip indicator..........................496
SRS airbags ..........................495
Tire pressure warning light ....499U
V
W
GW Refer to

630
What to do if...
What to do if...
A tire puncturesP. 523If you have a flat tire
The hybrid system does not start
P. 538If the hybrid system will not start
P. 135Immobilizer system
P. 543If the 12-volt battery is
discharged
The high coolant temperature
warning light flashes or comes on
“HYBRID SYSTEM OVERHEAT”
is displayed
Steam can be seen coming
from under the hood
P. 549If your vehicle overheats
The key is lostP. 540If you lose your keys
The 12-volt battery runs outP. 543If the 12-volt battery is
discharged
The doors cannot be lockedP. 8 7Side doors
P. 9 3Back door
The vehicle is stuck in mud or
sandP. 554If the vehicle becomes stuck
A warning light or indicator
light comes onP. 493If a warning light turns on or a
warning buzzer sounds

631
What to do if...
■
Warning lights
P. 499
or
P. 495
or
P. 493P. 495
P. 494P. 496
P. 494P. 496
P. 496
or
P. 495P. 497
P. 495P. 497
Master warning light ABS warning light
Brake system warning
light (red indicatorF
Electric power steering
system warning light
Charging system
warning lightPre-collision system
warning light
G
High coolant
temperature warning
lightSlip indicator light
Brake system warning
light (yellow indicator)Malfunction indicator
lamp
Automatic headlight
leveling system
warning light
SRS warning lightCruise control indicator
light
G