2012 TOYOTA PRIUS Owners Manual

5
When trouble arises
497
5-2. Steps to take in an emergency
Warning lightWarning light/Details

(If equipped)
Automatic headlight level
ing system warning light
Indicates a malfunction in the automatic headlight level-
ing system

(Flashes)
(If equipped) Cruise control indicator
Indicates a malfunction in the cruise control/dynamic
radar cruise control

(Flashes)
(If equipped) Radar cruise control indicator
Indicates a malfunction in the dynamic radar cruise con-
trol

498 5-2. Steps to take in an emergency
Follow the correction procedures.After taking the specified steps to correct the suspected problem,
check that the warning light goes off.
Warning lightWarning light/DetailsCorrection procedure
Open door warning light
(warning buzzer)
*1
Indicates that a door is
not fully closed Check that all the
doors are closed.
Low fuel level warning
light Indicates remaining fuel
is approximately 1.6 gal.
(6.0 L, 1.3 Imp.gal.) or
less Refuel the vehicle.
Driver’s seat belt
reminder light (warning
buzzer)
*2
Warns the driver to fasten
his/her seat belts. Fasten the seat
belt.
(On the instrument panel)
Front passenger’s seat
belt reminder light
(warning buzzer)
*2
Warns the front passen-
ger to fasten his/her seat
belt.Fasten the seat
belt.

5
When trouble arises
499
5-2. Steps to take in an emergency
Warning lightWarning light/DetailsCorrection
procedure
Tire pressure warning
light
When the light comes
on:
Low tire inflation pres-
sure such as
• Natural causes ( P. 501)
• Flat tire ( P. 523) Adjust the tire
inflation pressure
to the specified
level.
The light will turn
off after a few
minutes. In case
the light does
not turn off even
if the tire infla-
tion pressure is
adjusted, have
the system
checked by your
Toyota dealer.
When the light comes
on after blinking for 1
minute:
Malfunction in the tire
pressure warning sys-
tem
(  P. 503) Have the system
checked by your
Toyota dealer.
Master warning light
The warning light comes
on and flashes to indicate
that the master warning
system has detected a
malfunction. 
P. 5 0 7

500 5-2. Steps to take in an emergency
*1: Open door warning buzzer:The open door warning buzzer sounds to alert one or more of the doors is
not fully closed (with the vehicle having reached a speed of 3 mph [5 km/h]).
*2: Seat belt warning buzzer:
The driver’s and front passenger’s seat belts reminder sounds to alert the
driver and front passenger that his or her seat belt is not fastened. The
buzzer sounds intermittently for 10 seconds after the vehicle has reached a
speed of at least 12 mph (20 km/h). Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 20 more seconds.
■ SRS warning light
This warning light system monitors the airbag sensor assembly, front impact
sensors, side impact sensors (front), si de impact sensors (rear), driver’s seat
position sensor, driver’s seat belt buckle switch, front passenger occupant
classification system (ECU and sensors), “AIR BAG ON” indicator light, “AIR
BAG OFF” indicator light, front passenger’s seat belt buckle switch, seat belt
pretensioner assemblies, airbags, interconnecting wiring and power
sources. ( P. 140)
■ Front passenger occupant classifi cation system (ECU and sensors),
seat belt reminder and warning buzzer
● If luggage is placed on the front passenger seat, the front passenger
occupant classification system (ECU and sensors) may cause the warn-
ing light to flash and the warning buzzer to sound even if a passenger is
not sitting in the seat.
● If a cushion is placed on the seat, the front passenger occupant classifi-
cation system (ECU and sensors) may not detect a passenger, and the
warning light may not operate properly.

5
When trouble arises
501
5-2. Steps to take in an emergency
■
Electric power steering system warning light
When the 12-volt battery charge becomes insufficient or the voltage tempo-
rarily drops, the electric power steering system warning light may come on.
■ If the malfunction indicator lamp comes on while driving
First check the following:
● Is the fuel tank cap loose?
If it is, tighten it securely.
The malfunction indicator lamp will go off after several driving trips.
If the malfunction indicator lamp does not go off even after several trips, con-
tact your Toyota dealer as soon as possible.
■
When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level.
Pushing the tire pressure warning re set switch will not turn off the tire
pressure warning light.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such
as natural air leaks and tire inflat ion pressure changes caused by tem-
perature. In this case, adjusting the tire inflation pressure will turn off the
warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning
valve and transmitter. If a tire goes flat, the tire pressure warning light will
not turn off even though the flat tire has been replaced with the spare
tire. Replace the spare tire with the re paired tire and adjust the tire infla-
tion pressure. The tire pressure wa rning light will go off after a few min-
utes.

502 5-2. Steps to take in an emergency
■If the tire pressure warning system is not functioning
The tire pressure warning system will be disabled in the following condi-
tions:
(When the condition becomes normal, the system will work properly.)
●If tires not equipped with tire pressure warning valves and transmit-
ters are used
●If the ID code on the tire pressure warning valves and transmitters is
not registered in the tire pressure warning computer
●If the tire inflation pressure is 73 psi (500 kPa, 5.1 kgf/cm2 or bar) or
higher
The tire pressure warning system may be disabled in the following condi-
tions:
(When the condition becomes normal, the system will work properly.)
●If electronic devices or facilities using similar radio wave frequencies
are nearby
●If a radio set at a similar frequency is in use in the vehicle
●If a window tint that affects the radio wave signals is installed
●If there is a lot of snow or ice on the vehicle, particularly around the
wheels or wheel housings
●If non-genuine Toyota wheels are used (Even if you use Toyota
wheels, the tire pressu re warning system may not work properly with
some types of tires.)
●If tire chains are used

5
When trouble arises
503
5-2. Steps to take in an emergency
■If the tire pressure warning light frequently comes on after blinking
for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1
minute when the “POWER” switch
is turned to ON mode, have it
checked by your Toyota dealer.
■ Customization
The vehicle speed linked seat belt reminder buzzer can be disabled.
(Customizable features P. 590) However, Toyota recommends that the
seat belt reminder buzzer be operational to alert the driver and front passen-
ger when seat belts are not fastened.
CAUTION
■ If both the ABS and the brake system warning lights remain on
Stop your vehicle in a safe place immediately and contact your Toyota
dealer. The vehicle will become extremely unstable during braking, and the
ABS system may fail, which could cause an accident resulting in death or
serious injury.
■ When the electric power steering system warning light comes on
The steering wheel may become extremely heavy.
If the steering wheel becomes heavier than usual when operating, hold
firmly and operate using more force than usual.

504 5-2. Steps to take in an emergency
CAUTION
■If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could
cause a loss of vehicle control and result in death or serious injury.
●Stop your vehicle in a safe place as soon as possible. Adjust the tire
inflation pressure immediately.
●If the tire pressure warning light comes on even after tire inflation pres-
sure adjustment, it is pr obable that you have a flat tire. Check the tires.
If a tire is flat, change it with th e spare tire and have the flat tire
repaired by the nearest Toyota dealer.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate,
you could lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning syste m may not activate immediately.
■Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly
when cold and inflated to the inflation pressure recommended by the
vehicle manufacturer on the vehicle placard or tire inflation pressure
label (tire and load information label). (If your vehicle has tires of a differ-
ent size than the size indicated on the vehicle placard or tire inflation
pressure label [tire and load information label], you should determine the
proper tire inflation pr essure for those tires.)