2012 TOYOTA PRIUS ECU

486 5-1. Essential information
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(s).
This should only be attempted
on hard surfaced roads for short
distances at under 18 mph
(30 km/h).
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.

5
When trouble arises
487
5-1. Essential information
Installing towing eyelets
Remove the eyelet cover using a
flathead screwdriver.
To prevent damage, cover the tip
of the screwdriver with a rag.
Insert the towing eyelet into the
hole and tighten partially by
hand.
Tighten down the towing eyelet
securely using a wheel nut
wrench.
STEP 1
STEP 2
STEP 3

490 5-1. Essential information
CAUTION
■Caution while towing
●Use extreme caution when towing the vehicle.
Avoid sudden starts or erratic driving maneuvers which place excessive
stress on the emergency towing eyelets and the cables or chains. Always
be cautious of the surroundings and other vehicles while towing.
● Do not turn the “POWER” switch off.
This may lead to an accident as the front wheels will be locked by the
parking lock.
● If the hybrid system is off, the power assist for the brakes and steering will
not function, making steering and braking more difficult.
■ 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. This
may lead to accidents that cause serious injury or even death.

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.

5
When trouble arises
509
5-2. Steps to take in an emergency
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
(If equipped) Indicates a malfunction in the LED headlight system.
Indicates a malfunction in the P position control sys-
tem.
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.
(Flashes)
(If equipped) Indicates a malfunction in the pre-collision system.
A buzzer also sounds.

5
When trouble arises
525
5-2. Steps to take in an emergency
Remove the jack handle.
Unhook the tightening strap.
After storing the jack, make
sure it is securely held by the
tightening strap.
Taking out the spare tire
Loosen the center fastener that
secures the spare tire.
ITI52P200a
STEP 2
CAUTION
■Service plug
Be careful not to hit the service plug when loading or unloading the tool
holder or the spare tire. (P. 3 6 )

532 5-2. Steps to take in an emergency
Pass the belt through the buckle
and secure the tire firmly. Check
that the belt is securely held by
the buckle.
The belt cannot be fastened
securely if the buckle is facing
the wrong direction.
STEP 4
■The compact spare tire
●The compact spare tire is identified by the label “TEMPORARY USE
ONLY” on the tire sidewall.
Use the compact spare tire temporarily, and only in an emergency.
●Make sure to check the tire inflation pressu re of the compact spare
tire. ( P. 569)
■After completing the tire change
The tire pressure warnin g system must be reset. ( P. 439)
■When using the compact spare tire
As the compact spare tire is not equipped with a tire pressure warning
valve and transmitter, low inflation pressure of the spare tire will not be
indicated by the tire pressure warn ing system. Also, if you replace the
compact spare tire after the tire pressure warning light comes on, the
light remains on.