warning TOYOTA PRIUS 2010 3.G Workshop Manual

450 4-3. Do-it-yourself maintenance
PRIUS_U (OM47668U) U.S.A.
NOTICE
■Repairing or replacing tires, wheels and tire pressure warning
valves and transmitters
When removing or fitting the wheels, tires or the tire pressure warning
valve and transmitter, contact your Toyota dealer as the tire pressure
warning valve and transmitter may be damaged if not handled correctly.
■To avoid damaging the tire pressure warning valves and transmit-
ters
Do not use liquid sealants on flat tires.
■Driving on rough roads
Take particular care when driving on roads with loose surfaces or pot-
holes. 
These conditions may cause losses in tire inflation pressure, reducing
the cushioning ability of the tires. In addition driving on rough roads may
cause damage to the tires themselves, as well as the vehicle’s wheels
and body.
■Low profile tires (215/45R17 tires)
Low profile tires may cause greater damage than usual to the wheel
when receiving impact from the road surface. Therefore pay attention to
the following:
●Be sure to use proper tire inflation pressure. If tires are under-inflated,
they may be damaged more severely.
●Avoid pot holes, uneven pavemen t, curbs and other road hazards.
Failure to do so can lead to severe tire and wheel damage.
■If tire inflation pressures become low while driving
Do not continue driving, or your tires and/or wheels may be ruined.

456 4-3. Do-it-yourself maintenance
PRIUS_U (OM47668U) U.S.A.
■When replacing wheels
The wheels of your Toyota are equipped with tire pressure warning
valves and transmitters that allow the tire pressure warning system to
provide advanced warning in the event of a loss in tire inflation pressure.
Whenever wheels are replaced, the tire pressure warning valves and
transmitters must be installed. (P. 442)
CAUTION
■When replacing wheels
●Do not use wheels that are a different size from those recommended in
the Owner’s Manual, as this may re sult in loss of handling control.
●Never use an inner tube in a leaking wheel which is designed for a
tubeless tire. Doing so may result in an accident, causing death or seri-
ous injury.
NOTICE
■Replacing tire pressure warning valves and transmitters
●Because tire repair or replacement may affect the tire pressure warn-
ing valves and transmitters, make sure to have tires serviced by your
Toyota dealer or other qualified service shop. In addition, make sure to
purchase your tire pressure warning valves and transmitters at your
Toyota dealer.
●Ensure that only genuine Toyota wheels are used on your vehicle. 
Tire pressure warning valves and transmitters may not work properly
with non-genuine wheels.

When trouble arises5
485
PRIUS_U (OM47668U) U.S.A.
5-1. Essential informationEmergency flashers ......... 486
If your vehicle needs to 
be towed ........................ 487
If you think something is 
wrong ............................. 493
Event data recorder ......... 494
5-2. Steps to take in an 
emergency
If a warning light turns on or 
a warning buzzer 
sounds... ........................ 496
If a warning message is 
displayed ........................ 508
If you have a flat tire......... 524
If the hybrid system will 
not start .......................... 538
If you lose your keys ........ 540
If the electronic key does 
not operate properly....... 541
If the 12 volt battery is 
discharged ..................... 543
If your vehicle 
overheats ....................... 548
If the vehicle becomes 
stuck .............................. 553

496
PRIUS_U (OM47668U) U.S.A.
5-2. Steps to take in an emergency
If a war ning light turns on or a warning buzzer sounds...
Stop the vehicle immediately. Continuing to drive the vehicle
may be dangerous.The following warning indicates a possible problem in the brake sys-
tem. Immediately stop the vehicle in a safe place and contact your
Toyota dealer.
*: Parking brake engaged warning buzzer: 
A buzzer will sound if the vehicle is driven at a speed of approximately 3 mph
(5 km/h) or more.
Warning lightWarning light/Details

(U.S.A.)

(Canada)
Brake system warning light and warning buzzer* (red
indicator)
• Low brake fluid
• Malfunction in the brake system This light also comes on when the parking brake is not
released. If the light turns off after the parking brake is
fully released, the system is operating normally.
Calmly perform the following actions if any of the warning lights turn
on or flash. If a light turns on or flashes, but then turns off, this does
not necessarily indicate a malfunction in the system.

5
When trouble arises
497
5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
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.
Have the vehicle inspected immediately.Failing to investigate the cause of the following warnings may lead to
the system operating abnormally and possibly cause an accident.
Have the vehicle inspected by your Toyota dealer immediately.
Warning lightWarning light/Details
Charging system warning light
Indicates a malfunction in the vehicle’s charging system.
Warning lightWarning light/Details
(U.S.A.)
(Canada) Malfunction indicator lamp
Malfunction in:
• The emission control system;
• The electronic engine control system;
• The electronic hybrid system control system; or
• The electronic throttle control system.
SRS warning light Malfunction in:
• The SRS airbag system;
• Front passenger occupant classification system; or
• The seat belt pretensioner system.

498 5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
Warning lightWarning light/Details
Automatic headlight leveling system warning light (if
equipped)
Indicates a malfunction in the automatic headlight level-
ing system.

(U.S.A.)

(Canada)
ABS warning lightMalfunction in:
• The ABS; or
• The brake assist system.
Brake system warning light (yellow indicator) Malfunction in the electronically controlled brake sys-
tem.
Electric power steering system warning light Malfunction in the EPS (Electric Power Steering).
Pre-collision system warn ing light (if equipped)
Indicates a malfunction in the pre-collision system.

5
When trouble arises
499
5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
Follow the correction procedures.
After taking the specified steps to correct the suspected problem,
check that the warning light turns off.
Warning lightWarning light/DetailsCorrection procedure
Open door warning light 
(warning buzzer)
*1
A door or a back door is
not fully closed.
Check that all
doors and the back
door are closed.
Low fuel level warning
light Remaining fuel
(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 belt. 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.

500 5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
Warning lightWarning light/DetailsCorrection procedure
Tire pressure warning
light
When the light comes on:
Low tire inflation pres-
sure. Adjust the tire
inflation pressure.
When the light comes on
after blinking for 1 minute:
Malfunction in the tire
pressure warning system. Have the system
checked by your
Toyota dealer.
High coolant tempera-
ture warning light
Indicates high engine
coolant temperature P. 5 4 8
Master warning light A buzzer sounds and the
warning light comes on
and flashes to indicate
that the master warning
system has detected a
malfunction. P. 5 0 8

5
When trouble arises
501
5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
*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 hav
ing reached a speed of 3 mph [5 km/h]).
*2: Driver’s and front passenger’s seat belt reminder 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 lest 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.
■If the malfunction indicator lamp comes on while driving
First check whether the fuel tank cap is loose. If it is, tighten it securely.
The light will go off after taking several driving trips. 
If the light does not go off even after several trips, contact your Toyota dealer
as soon as possible.
■ Electric power steering warning light
When the voltage is low or drops, the electric power steering warning light
may come on.

502 5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
■SRS warning light
This warning light system monitors the following:
● The airbag sensor assembly
● Front airbag sensors
● The curtain shield airbag sensors
● The side and curtain shield airbag sensor assemblies
● The driver’s seat position sensor
● Driver’s seat belt buckle switch
● The front passenger occupant classification ECU
● The pressure sensor
● The belt tension sensor
● “AIR BAG ON” and “AIR BA G OFF” indicator lights
● Front passenger’s seat belt buckle switch
● The inflators
● The warning light
● The interconnecting wiring and power sources
■ Open moon roof reminder buzzer
The buzzer indicates that the moon roof is not fully closed with the hybrid
system off and the driver’s door opened.