warning light TOYOTA PRIUS 2017 4.G Repair Manual

642
PRIUS_OM_OM47B54U_(U)
7-3. Do-it-yourself maintenance
WARNING
■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 it 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.
● Check the wattage of the bulb before installing to prevent heat damage.

643
PRIUS_OM_OM47B54U_(U)
8When trouble arises
8-1. Essential informationEmergency flashers .......... 644
If your vehicle has to be stopped in an
emergency ...................... 645
8-2. Steps to take in an emergency
If your vehicle needs to be towed ......................... 646
If you think something is wrong .............................. 652
If a warning light turns on or a warning buzzer
sounds ............................ 653
If a warning message is displayed......................... 663
If you have a flat tire (vehicles with
spare tire)........................ 670
If you have a flat tire (vehicles without
spare tire)........................ 684
If the hybrid system will not start ........................... 703
If the electronic key does not operate properly........ 705
If the 12-volt battery is discharged ...................... 708
If your vehicle overheats ... 714
If the vehicle becomes stuck ............................... 719

652
PRIUS_OM_OM47B54U_(U)
8-2. Steps to take in an emergency
If you think something is wrong
●Fluid leaks under the vehicle
(Water dripping from the air co nditioning after use is normal.)
● Flat-looking tires or uneven tire wear
● High coolant temperature warning light flashes or comes on
● 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
● Engine missing, stumbling or running roughly
● 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, spon gy feeling, pedal almost touches
the floor
If you notice any of the follow ing symptoms, your vehicle proba-
bly needs adjustment or repair. Contact your Toyota dealer as
soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

653
PRIUS_OM_OM47B54U_(U)
8
When trouble arises
8-2. Steps to take in an emergency
If a warning light turns on or a warning
buzzer sounds
Calmly perform the following actions if any of the warning lights
comes on or flashes. If a light comes on or flashes, but then
goes off, this does not necessarily indicate a malfunction in the
system. However, if this continues to occur, have the vehicle
inspected by your Toyota dealer.
Warning light and warning buzzer list
Warning lightWarning light/Details/Actions
(U.S.A.)
(Canada)
Brake system warning light and warning buzzer (red
indicator)
*1
Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning
→ Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer. Continuing to drive the vehi-
cle may be dangerous.
Brake system warning light (yellow indicator)
Indicates a malfunction in:
• The regenerative braking system; or
• The electronically controlled brake system
→ Have the vehicle inspected by your Toyota dealer
immediately.
Charging system warning light
Indicates a malfunction in the vehicle’s charging system
→ Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer.
Low engine oil pressure warning light
(warning buzzer)
*2
Indicates that the engine oil pressure is too low
→ Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer.
(U.S.A.)
(Canada)
Malfunction indicator lamp Indicates a malfunction in:
• The hybrid system;
• The electronic engine control system; or
• The electronic throttle control system
→ Have the vehicle inspected by your Toyota dealer
immediately.

6548-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
SRS warning lightIndicates a malfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system
→ Have the vehicle inspected by your Toyota dealer
immediately.
(U.S.A.)
(Canada)
ABS warning light Indicates a malfunction in:
• The ABS; or
• The brake assist system
→ Have the vehicle inspected by your Toyota dealer
immediately.
(Red/yellow)
Electric power steering system warning light (warning
buzzer)
Indicates a malfunction in the EPS (Electric Power Steer-
ing) system
→ Have the vehicle inspected by your Toyota dealer
immediately.
(Flashes)
(If equipped)
PCS warning light
When the warning light flashes (and a buzzer sounds):
Indicates a malfunction in the PCS (Pre-Collision System)
→ Have the vehicle inspected by your Toyota dealer
immediately.
When the warning light flashes (and a buzzer does not
sound):
Indicates that the PCS (Pre-Collision System) is temporar-
ily unavailable, possibly due to either of the following:
• An area around the radar sensor or camera sensor being dirty or covered with condensation, ice, stickers,
etc.
→ Clear the dirt, condensation, ice, stickers, etc.
(→P. 270)
• Radar sensor or camera sensor operational conditions (such as temperature etc.) being not met
→ Driving is possible in th is case. The PCS (Pre-Colli-
sion System) will be enabled if the operational condi-
tions (such as temperature etc.) are met again.
When the warning light is illuminated:
Either the VSC (Vehicle Stability Control) system or PCS
(Pre-Collision System) is disabled or both are disabled.
→ To enable the PCS, enable both the VSC system and
PCS. ( →P. 279, 404)
Warning lightWarning light/Details/Actions

6558-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
8
When trouble arises
Slip indicator lightIndicates a malfunction in:
• The VSC system;
• The TRAC system; or
• The hill-start assist control system
→ Have the vehicle inspected by your Toyota dealer
immediately.
The light will flash when the ABS, VSC or TRAC system is
operating.
High coolant temperat ure warning light
• When the light flashes:
Indicates that the engine coolant temperature is too high
The light changes from a flashing to a solid light when
the temperature further increases
→ Immediately stop the vehicle in a safe place. ( →P. 714)
• When the light comes on without flashing: Indicates a malfunction in the exhaust heat recirculator
system
→ Have the vehicle inspected by your Toyota dealer
immediately.
(Flashes)
(If equipped)
ICS OFF indicator
Indicates a malfunction in the Intelligent Clearance Sonar
function
→ Have the vehicle inspected by your Toyota dealer.
The warning light will operate as follows, even when the
system is not malfunctioning:
• The light will come on when the Intelligent Clearance Sonar function is turned off ( →P. 346)
• The light will come on when the Intelligent Clearance Sonar function is operating ( →P. 350)
• The light will flash when the system cannot be temporar- ily used ( →P. 354)
Open door warning light (warning buzzer)*3
Indicates that a door is not fully closed
→ Check that all the doors are closed.
Low fuel level warning light
Indicates that remaining fuel is approximately 1.7 gal.
(6.4 L, 1.4 Imp.gal.) or less
→ Refuel the vehicle.
Warning lightWarning light/Details/Actions

6568-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
Seat belt reminder light (warning buzzer)*4
Warns the driver and/or front passenger to fasten their
seat belts
→ Fasten the seat belt.
If the front passenger’s seat is occupied, the front
passenger’s seat belt also needs to be fastened to
make the warning light (warning buzzer) turn off.
Rear passengers’ seat belt reminder lights (warning
buzzer) (U.S.A. only)
*5
Warns the rear passengers to fasten their seat belts
→ Fasten the seat belt.
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. 663
Tire pressure warning light
When the light comes on:
Low tire inflation pressure such as
• Natural causes ( →P. 659)
• Flat tire ( →P. 670, 684)
→ Adjust the tire inflation pressure to the specified
level.
The light will turn off af ter a few minutes. In case
the light does not turn off even if the tire inflation
pressure is adjusted, have the system checked by
your Toyota dealer.
When the light comes on after blinking for 1 minute:
Malfunction in the tire pressure warning system
( → P. 659)
→ Have the system checked by your Toyota dealer.
Brake Override System /Drive-Start Control/
Intelligent Clearance Sonar (symbol display)
*6
Indicates that:
• The Brake Override System is operating;
• The Brake Override System is malfunctioning;
• The Drive-Start Control is operating;
• The Drive-Start Control is malfunctioning; or
• The Intelligent Clearance Sonar (if equipped) is operat-
ing ( →P. 350)
→ Follow the instruction that are displayed on the multi-
information display.
Warning lightWarning light/Details/Actions

6578-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
8
When trouble arises
*1: Brake system warning buzzer:When there is a possible problem that could affect braking performance,
the warning light will come on and a warning buzzer will sound.
*2: Low engine oil pressure warning buzzer: A buzzer also sounds continuously for approximately 30 seconds at maxi-
mum in addition to the low engine oil pressure warning light when the
“READY” indicator is illuminated.
*3: 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]).
*4: Driver and front passenger’s seat belt warning buzzer:
The driver’s seat belt warning buzzer sounds to alert the driver that his or
her seat belt is not fastened. Once the power switch is turned to ON mode,
the buzzer sounds for 6 seconds. If the vehicle reaches a speed of 12 mph
(20 km/h), the buzzer sounds once. If the seat belt is still unfastened after
24 seconds, the buzzer will sound intermittently for 6 seconds. Then, if the
seat belt is still unfastened, the buzzer will sound in a different tone for 90
more seconds.
The front passenger’s seat belt warning buzzer sounds to alert the front
passenger that his or her seat belt is not fastened. The buzzer sounds
once if the vehicle reaches a speed of 12 mph (20 km/h). If the seat belt is
still unfastened after 24 seconds, the buzzer will sound intermittently for 6
seconds. Then, if the seat belt is still unfastened, the buzzer will sound in a
different tone for 90 more seconds.
*5: Rear passengers’ seat belt warning buzzer:The rear passengers’ seat belt warning buzzer sounds to alert the rear
passengers that his or her seat belt is not fastened. The buzzer sounds
intermittently for 6 seconds after the vehicle reaches a speed of 12 mph
(20 km/h). Then, if the seat belt is still unfastened, the buzzer will sound in
a different tone for 24 more seconds.
*6: This symbol is displayed on the multi-information display.
(If equipped)
LDA (Lane Departure Alert with steering control) system
(symbol display)
*6
Indicates that the LDA (Lane Departure Alert with steering
control) system has determined that the driver does not
have their hands on the steering wheel while the steering
control function is on
→ Firmly hold the steering wheel.
(Canada only)
Low engine oil pressure warning (symbol display)*6
Indicates that the engine oil pressure is too low
→ Immediately stop the vehicle in a safe place and con-
tact your Toyota dealer.
Warning lightWarning light/Details/Actions

6588-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact
sensors, side impact sensors (front), side impact sensors (front door\
), side
impact sensors (rear), driver’s seat belt buckle switch, front passenger occu-
pant classification system (ECU and sens ors), “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. 36)
■ Front passenger detection sensor, seat belt reminder and warning
buzzer
● If luggage is placed on the front passenger seat, the front passenger de\
tec-
tion sensor may cause the warning 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 sensor may not detect a passenger,
and the warning light may not operate properly.
■ 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 steer ing system warning light may come on
and the warning buzzer may sound.
■ If the malfunction indicator la mp comes on while driving
First check the following:
● Is the fuel tank empty?
If it is, fill the fuel tank immediately.
● 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.

6598-2. Steps to take in an emergency
PRIUS_OM_OM47B54U_(U)
8
When trouble arises
■When the tire pressure warning light comes on
Inspect the appearance of the tire to check that the tire is not punctured.
If the tire is punctured: → P. 670, 684
If the tire is not punctured:
Check the tire inflation pressure and adjust to the appropriate level. Initial-
izing the tire pressure warning syst em 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 ti re inflation pressure will turn off the
warning light (afte r a few minutes).
■When a tire is replaced with a spare tire
Vehicles with compact spare tire: Th e 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 tu rn off even though the flat tire has
been replaced with the spare tire. Repl ace the spare tire with the repaired
tire and adjust the tire inflation pr essure. The tire pressure warning light
will go off after a few minutes.
Vehicles with full-size spare tire: The spare tire is also equipped with a tire
pressure warning valve and transmitter. The tire pressure warning light
will turn on if the tire inflat ion pressure of the spare ti re is low. 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
repaired tire and adjust the tire inflation pressure. The tire pressure warn-
ing light will go off after a few minutes.
■Conditions that the tire pressure warning system may not function
properly
→ P. 6 1 0
■If the tire pressure warning light frequently comes on after blinking
for 1 minute
If the tire pressure warning light frequently comes on after blinking for
1 minute when the power switch is tu rned to ON mode, have it checked
by your Toyota dealer.
■ Warning buzzer
In some cases, the buzzer may not be heard due to being in a noisy location
or audio sound.