2010 TOYOTA PRIUS engine

483
4-3. Do-it-yourself maintenance
4
Maintenance and care
PRIUS_U (OM47668U) U.S.A.
■
Condensation build-up on th e inside of the lens
Contact your Toyota dealer for more information in the following situations.
Temporary condensation build-up on the inside of the headlight lens does
not indicate a malfunction.
● Large drops of water are built up on the inside of the lens.
● Water has built up inside the headlight.
■ LED lights
The headlight low beams (LED type), stop/tail lights and high mounted
stoplight consist of a number of LEDs. If any of the LEDs burn out, take your
vehicle to your Toyota dealer to have the light replaced.
■ Installing the engine under cover clip
Insert the clip.

5
When trouble arises
493
5-1. Essential information
PRIUS_U (OM47668U) U.S.A.
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably
needs adjustment or repair. Contact your Toyota dealer as soon as
possible.
■ Visible symptoms
●Fluid leaks under the vehicle 
(Water dripping from the air cond itioning after use is normal.)
● Flat-looking tires or uneven tire wear
■ Audible symptoms
●Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the hybrid system
■ Operational symptoms
●Engine missing, stumbling or running rough
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road
● Loss of brake effectiveness, s pongy feeling, pedal almost
touches the floor

494
5-1. Essential information
PRIUS_U (OM47668U) U.S.A.
Event data recorder
In a crash or a near car crash eventThe SRS airbag sensor assembly contains the EDR. In a crash or a
near car crash event, this device may record some or all of the follow-
ing information:
● Gasoline engine speed
● Whether the brake pedal was applied or not
● Vehicle speed
● To what extent the accelerator pedal was depressed
● Position of the transmission shift lever
● Whether the driver and front passenger wore seat belts or not
● Driver’s seat position
● SRS airbag deployment data
● SRS airbag system diagnostic data
● Front passenger’s occupant classification
The information above is intended to be used for the purpose of
improving vehicle safety performan ce. Unlike general data recorders,
the EDR does not record sound data such as conversation between
passengers.
Your vehicle has computers that monitor and control certain aspects
of your vehicle. These computers assi st in driving and maintaining
optimal vehicle performance.
Besides storing data useful for troubleshooting, there is an event
data recorder (EDR) that records data in a crash or a near car crash
event.

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.

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
509
5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
Stop the vehicle immediately.
A buzzer sounds and a warning message is shown on the multi-infor-
mation display. The following warnin gs indicate the possibility of dam-
age to the vehicle that may lead to an accident. Immediately stop the
vehicle in a safe place and contact your Toyota dealer.
Warning messageDetails
Indicates an abnormal engine oil pressure. The warning light may turn on if the engine oil pres-
sure is too low.
Indicates a malfunction in the hybrid system.

512 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 message turns off.
Warning messageDetailsCorrection procedure
(U.S.A. only) Indicates that the engine oil is
scheduled to be changed.
A buzzer also sounds.
Check the engine
oil, and change if
necessary.
Comes on approximately 4500
miles (7200 km) after the
engine oil is changed. (The
indicator will not work properly
unless the oil maintenance
data has been reset).
(U.S.A. only) Indicates that the engine oil
should be changed.
A buzzer also sounds.
Check and change
the engine oil.
Comes on approximately 5000
miles (8000 km) after the
engine oil is changed (and the
oil maintenance data has been
reset).

516 5-2. Steps to take in an emergency
PRIUS_U (OM47668U) U.S.A.
Warning messageDetailsCorrection procedure
EV-Drive Mode cannot be
switched to. A buzzer also sounds. Use the EV-Drive
Mode when it
becomes available.
The EV-Drive Mode has been
automatically cancelled. A buzzer also sounds. Drive normally for a
short time.
■ After changing the engine oil (U.S.A. only)
Make sure to reset the oil maintenance data. ( P. 428)
■ Approach warning message
In the following instances, there is the possibility that the approach warning
will not activate even when the vehicle-to-vehicle distance decreases.
● When your vehicle and the vehicle ahead are traveling at the same
speed or the vehicle ahead is traveling more quickly than your vehicle.
● When the vehicle ahead is traveling at very low speed.
● Immediately after cruise control speed is set.
● At the instant the accelerator pedal is depressed.