ECU TOYOTA PRIUS 2015 4.G Workshop Manual

482 4-3. Do-it-yourself maintenance
PRIUS_OM_OM47A17U_DVD_(U)
Replace the light bulb, and install
the bulb base.
Align the 3 tabs on the light bulb
with the mounting, and insert.
Turn and secure the bulb base.
Shake the bulb base gently to
check that it is not loose, turn the
headlights on once and visually
confirm that no light is leaking
through the mounting.
STEP 3
STEP 4

492 4-3. Do-it-yourself maintenance
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CAUTION
■Replacing light bulbs
●Be sure to stop the hybrid system and turn off the lights. Do not attempt to
replace the bulb immediately after turning off the lights.
The bulbs become very hot and may cause burns.
● Do not touch the glass portion of the light bulb with bare hands. When i\
t is
unavoidable to hold the glass portion, use and hold with a clean dry cloth
to avoid getting moisture and oils on the bulb.
Also, if the bulb is scratched or dropped, it may blow out or crack.
● Fully install light bulbs and any parts used to secure them. Failure to do so
may result in heat damage, fire, or water entering the headlight unit. This
may damage the headlights or cause condensation to build up on the lens.
● Do not attempt to repair or disassemble light bulbs, connectors, electric
circuits or component parts.
Doing so may result in death or serious injury due to electric shock.
■ To prevent damage or fire
Make sure bulbs are fully seated and locked.

498 5-1. Essential information
PRIUS_OM_OM47A17U_DVD_(U)
Emergency towingIf a tow truck is not available in an emergency, your vehicle may be
temporarily towed using a cable or chain secured to the emergency
towing eyelet. This should only be attempted on hard surfaced roads
for short distances at low speeds.
A driver must be in the vehicle to steer and operate the brakes. The
vehicle’s wheels, drive train, axles, steering and brakes must be in
good condition.
Emergency towing procedure
Take out the towing eyelet. ( P. 537)
Remove the eyelet cover using a
flathead screwdriver.
To protect the bodywork, place a
rag between the screwdriver and
the vehicle body as shown in the
illustration.
Insert the towing eyelet into the
hole and tighten partially by
hand.
STEP 1
STEP 2
STEP 3

5
When trouble arises
499
5-1. Essential information
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Tighten down the towing eyelet
securely using a wheel nut
wrench or hard metal bar.
Securely attach a cable or chain to the towing eyelet.
Take care not to damage the vehicle body.
Enter the vehicle being towed and start the hybrid system.
If the hybrid system does not start, turn the “POWER” switch to ON
mode.
Shift the shift position to N and release the parking brake.
STEP 4
■ While towing
If the hybrid system is off, the power assist for the brakes and steering will
not function, making steering and braking more difficult.
■ Wheel nut wrench
Wheel nut wrench is installed under the center auxiliary box. ( P. 537)
STEP 5
STEP 6
STEP7

500 5-1. Essential information
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CAUTION
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When towing the vehicle
■ While towing
●When towing using cables or chains, avoid sudden starts, etc. which place
excessive stress on the towing eyelet, cables or chains. The towing eyelet,
cables or chains may become damaged, broken debris may hit people and
cause serious damage.
● Do not turn the “POWER” switch off.
This may lead to an accident as the front wheels will be locked by the
parking lock.
■ Installing towing eyelets to the vehicle
Make sure that towing eyelets are installed securely.
If not securely installed, towing eyelets may come loose during towing.
Be sure to transport the vehicle with the
front wheels raised or with all four wheels
raised off the ground.
If the vehicle is towed with the front
wheels contacting the ground, the driv-
etrain and related parts may be damaged
or electricity generated by the operation
of the motor may cause a fire to occur
depending on the nature of the damage
or malfunction.

510 5-2. Steps to take in an emergency
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*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 door), side impact sensors (front), side
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 BA G OFF” indicator light, front passen-
ger’s seat belt buckle switch, seat belt pretensioner assemblies, airbags,
interconnecting wiring and power sources. ( P. 141)
■ 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
511
5-2. Steps to take in an emergency
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■
Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the voltage tempo-
rarily drops, the electric power steering system warning light may come on
and the warning buzzer may sound.
■ 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.

518 5-2. Steps to take in an emergency
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Stop the vehicle immediately.A buzzer sounds and a warning message is shown on the multi-infor-
mation display. The following warnings 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. In this situation, there is a possibility that the parking
lock mechanism will not work.
When parking, park the vehicle on a flat surface and
apply the parking brake securely.

5
When trouble arises
519
5-2. Steps to take in an emergency
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Have the vehicle inspected immediately.
Failure 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 messageDetails
Indicates a malfunction in the shift control system. In this situation, there is a possibility that the parking
lock mechanism will not work.
When parking, park the vehicle on a flat surface and
apply the parking brake securely. Also, it may not be
possible to turn the “POWER” switch off. If this hap-
pens, applying the parking brake will enable the
switch to be turned off.
Indicates a malfunction in the shift control system. A buzzer also sounds.
• The parking lock mechanism may not function. When parking, park the vehicle on a flat surface and
apply the parking brake securely.
• The hybrid system may not be able to start.
• It may not be possible to turn the “POWER” switch off. If this happens, applying the parking brake will
enable the switch to be turned off.

530 5-2. Steps to take in an emergency
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Have the malfunction repaired immediately.If any of the following warnings is displayed when a hybrid system
start operation is performed, perform the appropriate action accord-
ing to the warning message display.
Warning messageDetailsCorrection procedure
Indicates an insufficient 12-volt
battery charge. A buzzer also sounds.
• The parking lock mechanism may not function.
• The hybrid system may not be able to start.
• It may not be possible to turn the “POWER” switch off.
If this happens, applying the
parking brake will enable the
switch to be turned off. When parking, park
the vehicle on a flat
surface and apply
the parking brake
securely.
Charge or replace
the 12-volt battery.
After charging the
12-volt battery, the
message may con-
tinue to be dis-
played until the
shift position is
changed from P.