2012 TOYOTA PRIUS battery

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.

514 5-2. Steps to take in an emergency
Warning messageDetailsCorrection procedure
(If equipped) Indicates that the LKA is not
currently functional. Restart the LKA.
In case of over-
heating, the system
will become func-
tional once the sys-
tem cools down.
Alerts the driver that the vehi-
cle is out of the lanes (while
the LKA system is operating). A buzzer also sounds. The
lane markings and/or the
steering wheel marking flash.
At the same time,
will appear on the
head-up display (the image
flashes). Check around the
vehicle and back to
inside of the lane
markings.
The hybrid system has over-
heated. A buzzer also sounds.
This message may be dis-
played when driving under
severe operating conditions.
(For example, when driving
up a long steep hill.) Stop and check.
(
P. 549)
(Flashes) The hybrid battery (traction
battery) is low.
A buzzer also sounds. When stopping the
vehicle for a long
period of time, shift
the shift position to
P. The hybrid bat-
tery (traction bat-
tery) cannot be
charged with the
shift position in N.

5
When trouble arises
515
5-2. Steps to take in an emergency
Warning messageDetailsCorrection
procedure
(Flashes) The hybrid battery (traction
battery) power has dropped
because a long period of time
has elapsed after shifting the
shift position to N.
A buzzer also sounds. Restart the hybrid
system when start-
ing the vehicle.
(Flashes) The transmission is out of P
when attempting to start the
hybrid system.
Shift the shift posi-
tion to P before
pressing the
“POWER” switch.
(Flashes) The driver’s door is opened
when the transmission is out of
P with the hybrid system on.
Shift the shift posi-
tion to P.
(Flashes) Indicates that the accelerator
pedal is depressed while the
shift position is in N.
A buzzer also sounds. Release the accel-
erator pedal and
shift the shift posi-
tion to D or R.
EV drive mode cannot be
switched to. A buzzer also sounds.
The reason why EV drive
mode cannot be used is
shown on the second line
(may not be shown in some
instances.) Use the EV drive
mode when it
becomes available.

5
When trouble arises
521
5-2. Steps to take in an emergency
Interior
buzzerExterior buzzerWarning messageDetailsCorrection procedure
Contin-
uous Contin-
uous
(Displayed alternately)(Flashes) An open door
other than the
driver’s door is
closed while the
electronic key is
outside the
detection range
and the
“POWER”
switch is in
ACCESSORY
or ON mode
with the shift
position not in P.
• Shift the
shift posi-
tion to P.
• Confirm the loca-
tion of the
electronic
key.
Once 
(Comes on for 15 seconds.)
The electronic
key battery is
low. Replace
the bat-
tery.
(
P. 454)
Once 
(Flashes)An open door
has been
closed and the
“POWER”
switch has been
turned twice to
the ACCES-
SORY mode
from OFF. Press the
“POWER”
switch
while
applying
the
brakes.

522 5-2. Steps to take in an emergency
InteriorbuzzerExterior buzzerWarning messageDetailsCorrection procedure
Once 
(Flashes)The elec-
tronic key
does not
operate
properly.
P. 541
 Power
was
turned off
due to
the auto-
matic
power off
function.Next time when
starting the
hybrid system,
increase the
engine speed
slightly and
maintain that
level for approxi-
mately 5 min-
utes to recharge
the battery.
NOTICE
■
While the engine oil level warning is displayed
Continued engine operation with low engine oil will damage the engine.
■ Engine oil maintenance message
The warning message is based on the projected driving range after engine
oil maintenance message is reset.
The system does not monitor the purity of the engine oil.

538
5-2. Steps to take in an emergency
If the hybrid system will not start
Reasons for the hybrid system not starting vary depending on the
situation. Check the following a nd perform the appropriate proce-
dure:
■ The hybrid system will not start even though the correct
starting procedure is being followed ( P. 192)
One of the following may be the cause of the problem:
● The electronic key may not be functioning properly.
*
(  P. 541)
● There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle.
● There may be a malfunction in the immobilizer system.
*
(  P. 135)
● There may be a malfunction in the P position control system.
*
( P. 197, 509)
*: It may not be possible to shift the shift position from P to another
position.
■ The interior lights and headlights are dim, or the horn does
not sound or sounds at a low volume
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. ( P. 543)
● The 12-volt battery terminal c onnections may be loose or cor-
roded.

5
When trouble arises
539
5-2. Steps to take in an emergency
Emergency start function
When the hybrid system does not start, the following steps can be
used as an interim measure to st art the hybrid system if the
“POWER” switch is functioning normally:
Set the parking brake.
Turn the “POWER” switch to ACCESSORY mode.
Press and hold the “POWER” switch for about 15 seconds
while depressing the brake pedal firmly.
Even if the hybrid system can be started using the above steps, the
system may be malfunctioning. Have the vehicle inspected by your
Toyota dealer.
■ The interior lights and headlights do not turn on, or the horn
does not sound
One of the following may be the cause of the problem:
●One or both of the 12-volt ba ttery terminals may be discon-
nected.
● The 12-volt battery may be discharged. ( P. 543)
Contact your Toyota dealer if the problem cannot be repaired, or if
repair procedures are unknown.
STEP 1
STEP 2
STEP 3

5
When trouble arises
541
5-2. Steps to take in an emergency
If the electronic key does not operate properly
Locking and unlocking the doorsUse the mechanical key (P. 58)
in order to perform the following
operations:
Locks all the doors
Unlocks the door
Turning the key rearward unlocks
the driver’s door. Turning the key
once again within 3 seconds
unlocks the other doors.
If communication between the electronic key and vehicle is inter-
rupted ( P. 72) or the electronic key cannot be used because the
battery is depleted, the smart key system and wireless remote con-
trol cannot be used. In such cases, the doors can be opened and the
hybrid system can be started by following the procedure below.
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