warning light TOYOTA PRIUS C 2020 Repair Manual

4848-2. Steps to take in an emergency
PRIUS c_U
■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 belt buckle switch, front passenger occu-
pant classification system, “AIR BAG ON” indicator light, “AIR BAG OFF” indi-
cator light, front passenger’s seat belt buckle switch, seat be lt pretensioners
(front), airbags, interconnecting wiring and power sources. ( P. 41)
■ Front passenger detection senso r, passenger seat belt reminder and
warning buzzer
● If luggage is placed on the front passenger seat, the front pas senger detec-
tion sensor may cause the warning light to flash and the warnin g 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 wa rning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the vol tage 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 empty?
If it is, fill the fuel tank immediately.
● Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after several trips, contact 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. Push-
ing the tire pressur e warning reset switch will not turn off the tire pressure
warning light.
■The tire pressure warning light may come on due to natural caus es
The tire pressure warning light may come on due to natural caus es such
as natural air leaks and tire inflation pressure changes caused by tem-
perature. In this case, adjusting the tire inflation pressure w ill turn off the
warning light (afte r a few minutes).
■When a tire is replace d with a spare tire
The compact spare tire is not equipped with a tire pressure war ning 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 s pare tire.
Replace the spare tire with the repaired tire and adjust the ti re inflation
pressure. The tire pressure war ning light will go off after a few minutes.

4858-2. Steps to take in an emergency
8
When trouble arises
PRIUS c_U■
If the tire pressure warning system is not functioning
P. 440
■
If the tire pressure warning light frequently comes on after bl inking
for 1 minute
If the tire pressure warning light frequently comes on after bl inking for 1
minute when the power switch is turned to the “ON” position (ve hicles
without a smart key system) or the power switch is turned to ON mode
(vehicles with a smart key system) , have it checked by your Toyota
dealer.
■ Customization that can be configured at Toyota dealer
The vehicle speed linked seat belt reminder buzzer can be disab led. (Cus-
tomizable features: P. 560) However, Toyota recommends that the seat belt
reminder buzzer be operational to alert the driver and front pa ssenger when
seat belts are not fastened.
■ Warning buzzer
In some cases, the buzzer may not be heard because of noisy pla ce or an
audio sound.
WARNING
■ When the electric power steering system warning light comes on
The steering wheel may become extremely heavy.
When steering wheel operations are heavier than usual, grip the steering
wheel firmly and operate it using more force than usual.
■
If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could
cause a loss of vehicle control and result in death or serious injury.
●Stop your vehicle in a safe place as soon as possible. Adjust t he tire
inflation pressure immediately.
●If the tire pressure warning light comes on even after tire inf lation pres-
sure adjustment, it is probable that you have a flat tire. Chec k the tires.
If a tire is flat, change it with the spare tire and have the f lat tire
repaired by the nearest Toyota dealer.
●Avoid abrupt maneuvering and braking. If the vehicle tires dete riorate,
you could lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

4868-2. Steps to take in an emergency
PRIUS c_U
WARNING
■Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly
when cold and inflated to the inflation pressure recommended by the
vehicle manufacturer on the vehicle placard or tire inflation p ressure
label (tire and load information label). (If your vehicle has t ires of a dif-
ferent size than the size indica ted on the vehicle placard or tire inflation
pressure label [tire and load information label], you should de termine
the proper tire inflation p ressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire
pressure monitoring system (TPMS -tire pressure warning system) that
illuminates a low tire pressure telltale (tire pressure warning light) when
one or more of your tires is significantly under-inflated. Acco rdingly,
when the low tire pressure telltale (tire pressure warning ligh t) illumi-
nates, you should stop and check your tires as soon as possible , and
inflate them to the proper pressure. Driving on a significantly under-
inflated tire causes the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire tread lif e, and may
affect the vehicle’s handl ing and stopping ability.
Please note that the TPMS (tire pressure warning system) is not a sub-
stitute for proper tire maintena nce, and it is the driver’s responsibility to
maintain correct tire pressure, even if under-inflation has not reached
the level to trigger illumination of the TPMS low tire pressure telltale (tire
pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warn-
ing system) malfunction indicato r to indicate when the system is not
operating properly. The TPMS (tire pressure warning system) mal func-
tion indicator is combined with the low tire pressure telltale (tire pressure
warning light). When the system detects a malfunction, the tell tale will
flash for approximately one mi nute and then remain continuously illumi-
nated. This sequence will continue upon subsequent vehicle star t-ups
as long as the malfunction exists . When the malfunction indicator is illu-
minated, the system may not be able to detect or signal low tir e pres-
sure as intended.
TPMS (tire pressure warning system) malfunctions may occur for a vari-
ety of reasons, including the installation of replacement or al ternate tires
or wheels on the vehicle that prevent the TPMS (tire pressure w arning
system) from functioning properly. Always check the TPMS (tire pres-
sure warning system) malfunction telltale after replacing one or more
tires or wheels on your vehicle to ensure that the replacement or alter-
nate tires and wheels allow the TPMS (tire pressure warning sys tem) to
continue to function properly.

4888-2. Steps to take in an emergency
PRIUS c_U
Multi-information display
Warning message details and/or
correction procedures are shown
on the multi-information display.
Master warning light
The master warning light also
comes on or flashes in order to
indicate that a message is cur-
rently being displayed on the multi-
information display.
If any of the warning message or indicator comes on again after the
following actions have been per formed, contact your Toyota deal er.
If a warning message is displayed
If a warning is shown on the multi-information display, stay ca lm
and perform the following actions:
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4908-2. Steps to take in an emergency
PRIUS c_U
Indicates a malfunction in:
• The Automatic High Beam system
• The LED headlight systemA buzzer also sounds.
 Have the vehicle inspected by your Toyota
dealer.
Indicates that:
• There is a high possibility of a frontal collision;
or
• The pre-collision braking function is operating A buzzer also sounds.
 Check the vehicle's surroundings and take
evasive action if necessary.
(If equipped)
• Indicates a malfunction in the smart key system
• Indicates a malfunction in the steering lock sys-
tem
A buzzer also sounds.
 Have the vehicle inspected by your Toyota
dealer.
(If equipped)
Indicates a malfunction in the cruise control sys-
tem
A buzzer also sounds.
 Have the vehicle inspected by your Toyota
dealer.
Indicates a malfunction in the Brake Override
System
A buzzer also sounds.
 Have the vehicle inspected by your Toyota
dealer immediately.
Warning messageDetails/Actions
(Flashes)

4938-2. Steps to take in an emergency
8
When trouble arises
PRIUS c_UIndicates that the hybrid system has overheated
This message may be displayed when driving
under severe operating conditions. (For exam-
ple, when driving up a long steep hill.)
A buzzer also sounds.
 Stop and check. ( P. 529)
Indicates that the Automatic High Beam switch is
pressed while the headlights are in low beam.
Turn the high beam on.
Indicates that, since the VSC (Vehicle Stability
Control) system was turned off, the pre-collision
braking and pre-collision brake assist are dis-
abled (The pre-collision warning function will be
operational)
 Turn the VSC on. ( P. 240, 267)
Indicates that the pre-collision system is disabled.
 Have the vehicle inspected by your Toyota
dealer.
Indicates that the hybrid battery (traction battery)
is low A buzzer also sounds.
 When stopping the vehicle for a long
period of time, shift the shift lever to P. The
hybrid battery (traction battery) cannot be
charged with the shift position in N.
Warning messageDetails/Actions
(Flashes)

4948-2. Steps to take in an emergency
PRIUS c_UIndicates that the hybrid battery (traction battery)
power has dropped because a long period of time
has elapsed after shifting the shift lever to N
A buzzer also sounds.
 Shift the shift lever to P and restart the
hybrid system when starting the vehicle.
Indicates that the driver’s door was opened with
the shift position in N, D or B A buzzer also sounds.
 Shift the shift lever to P.
Indicates that the accelerator pedal is depressed
while the shift position is in N A buzzer also sounds.
 Release the accelerator pedal and shift the
shift lever to D, B or R.
Indicates that the power switch is turned to the
“ACC” or “LOCK” position (vehicles without a
smart key system) or the power switch is turned
to ACCESSORY mode or turned off (vehicles
with a smart key system) and the driver’s door is
opened while the lights are turned on A buzzer also sounds.
 Turn the lights off.
Warning messageDetails/Actions
(Flashes)
(Flashes)
(Flashes)
(Flashes)

4998-2. Steps to take in an emergency
8
When trouble arises
PRIUS c_U
Carrying out the corresponding action turns the message off.
After taking the specified steps to correct the suspected probl em,
check that the warning m essage and light go off.
Other displayed message
Displayed messageDetails/Actions
Maintenance of the hybrid battery (traction battery)
cooling component is required
The filter may be clogged, the air intake vent
may be blocked or there may be a gap in the
duct.
 If the air intake vent is dirty, refer to P. 404
for cleaning the air intake vent.
 If the message is being displayed and the air
intake vent is not dirty, have the vehicle
inspected at your Toyota dealer.
Have the malfunction repaired immediately. (vehicles with a
smart key system)
Interior
buzzerExterior buzzerWarning messageDetails/Actions
Once  The electronic key is not
detected when an attempt is
made to start the hybrid sys-
tem.

Start the hybrid system
with the electronic key
present.
(Flashes)

5038-2. Steps to take in an emergency
8
When trouble arises
PRIUS c_U

Power was turned off due to the
automatic power off function.
Next time when starting
the hybrid system,
increase the engine speed
slightly and maintain that
level for approximately 5
minutes to recharge the
12-volt-battery.
Once
The electronic key has a low
battery.
Replace the electronic key
battery. ( P. 451)
Once
The driver’s door was opened
and closed with the power
switch turned off and then the
power switch was put in
ACCESSORY mode twice with-
out the hybrid system being
started.
Press the power switch
while depressing the brake
pedal.
During a hybrid system starting
procedure in the event that the
electronic key was not function-
ing properly ( P. 520), the
power switch was touched with
the electronic key.
 Press the power switch
within 10 seconds of the
buzzer sounding.
Interior
buzzerExterior buzzerWarning messageDetails/Actions
(Flashes)

5158-2. Steps to take in an emergency
8
When trouble arises
PRIUS c_U
■The compact spare tire
●The compact spare tire is identified by the label “TEMPORARY USE
ONLY” on the tire sidewall.
Use the compact spar e tire temporarily, and only in an emergenc y.
●Make sure to check the tire inflation pressure of the compact s pare tire.
(  P. 5 4 3 )
■After completing the tire change
The tire pressure warni ng system must be reset. ( P. 436)
■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 warning system. Also, if you rep lace the
compact spare tire after the tire pressure warning light comes on, the light
remains on.
■If you have a flat front tire on a road covered with snow or ic e
Install the compact spare tire on one of the rear wheels of the vehicle.
Perform the following steps and f it tire chains to the front tires:
Replace a rear tire with the compact spare tire.
Replace the flat front tire with the tire removed from the rear of the vehi-
cle.
Fit tire chains to the front tires.
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