2021 HYUNDAI SONATA HYBRID engine

While Driving
6-138
Check spark plugs and ignition
system
Inspect your spark plugs as described in
chapter 8 and replace them if necessary.
Also check all ignition wiring and
components to be sure they are not
cracked, worn or damaged in any way.
Use approved window washer anti-
freeze in system
To keep the water in the window washer
system from freezing, add an approved
window washer anti-freeze solution in
accordance with instructions on the
container. Window washer anti-freeze is
available from an authorized HYUNDAI
dealer and most auto parts outlets. Do
not use engine coolant or other types
of antifreeze as these may damage the
paint finish.
Do not let your parking brake freeze
Under some conditions your parking
brake can freeze in the engaged position.
This is most likely to happen when
there is an accumulation of snow or
ice around or near the rear brakes or
if the brakes are wet. If there is a risk
the parking brake may freeze, apply
it only temporarily while you put the
gear selector lever in P and block the
rear wheels so the car cannot roll. Then
release the parking brake.
Do not let ice and snow accumulate
underneath
Under some conditions, snow and ice
can build up under the fenders and
interfere with the steering. When driving
in severe winter conditions where this
may happen, you should periodically
check underneath the car to be sure the
movement of the front wheels and the
steering components is not obstructed.
Don't place foreign objects
or materials in the engine
compartment
Placement of foreign object or materials
which prevent cooling of the engine, in
the engine compartment, may cause a
failure or combustion. The manufacturer
is not responsible for the damage caused
by such placement.
To keep locks from freezing
To keep the locks from freezing, squirt
an approved de-icer fluid or glycerine
into the key opening. If a lock is covered
with ice, squirt it with an approved de-
icing fluid to remove the ice. If the lock
is frozen internally, you may be able to
thaw it out by using a heated key. Handle
the heated key with care to avoid injury.

7. Emergency situations
Hazard Warning Flasher ........................................................................\
............7-2
In Case of an Emergency While driving
...........................................................7-2If the Engine Stalls While Driving ........................................................................\
........7-2
If the Engine Stalls at a Crossroad or Crossing ..........................................................7-2
If You Have a Flat Tire While Driving ........................................................................\
...7-3
If the Engine Will Not Start ........................................................................\
........7-3
If the 12 Volt Battery Is Discharged
..................................................................7-4Before Jump Starting ........................................................................\
...........................7-4
Jump Starting ........................................................................\
.......................................7-5
If the Engine Overheats ........................................................................\
.............7-7
Tire Pressure Monitoring System (TPMS)
........................................................7-9Check Tire Pressure ........................................................................\
..............................7-9
Tire Pressure Monitoring System ........................................................................\
.......7-10
Low Tire Pressure Telltale ........................................................................\
....................7-11
Low Tire Pressure LCD Display with Position Indicator .............................................7-11
TPMS (Tire Pressure Monitoring System) Malfunction Indicator .............................7-12
Changing a Tire with TPMS ........................................................................\
................7-12
If You Have a Flat Tire (with Spare Tire) ..........................................................7-14Jack and Tools ........................................................................\
.....................................7-14
Changing Tires ........................................................................\
.....................................7-15
Jack Label ........................................................................\
............................................7-19
If You Have a Flat Tire (with Tire Mobility Kit) ................................................7-20Introduction ........................................................................\
........................................7-20
Notes on the Safe Use of the Tire Mobility Kit ..........................................................7-21
Components of the Tire Mobility Kit ........................................................................\
.7-22
Using the Tire Mobility Kit ........................................................................\
.................7-23
Checking the Tire Inflation Pressure ........................................................................\
.7-25
Towing ........................................................................\
......................................7-26Towing Service ........................................................................\
...................................7-26
Removable Towing Hook ........................................................................\
....................7-27
Emergency Towing ........................................................................\
.............................7-28
Emergency situations
7

Emergency situations
7-2
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The hazard warning flasher serves as
a warning to other drivers to exercise
extreme caution when approaching,
overtaking, or passing your vehicle.
It should be used whenever emergency
repairs are being made or when the
vehicle is stopped near the edge of a
roadway.
To turn the hazard warning flasher on
or off, press the hazard warning flasher
button with the Engine Start/Stop button
in any position. The button is located in
the center fascia panel. All turn signal
lights will flash simultaneously.
• The hazard warning flasher operates
regardless of whether your vehicle is
in the READY state or not.
• The turn signals do not work when the
hazard flasher is on.
If the Engine Stalls While Driving
• Reduce your speed gradually, keeping
a straight line. Move cautiously off the
road to a safe place.
• Turn on your hazard warning flasher.
• Try to start the engine again. If your
vehicle will not start, contact an
authorized HYUNDAI dealer.
If the Engine Stalls at a Crossroad
or Crossing
If the engine stalls at a crossroads or
crossing, if safe to do so, shift the gear to
N (Neutral) and then push the vehicle to
a safe location.
HAZARD WARNING FLASHER IN CASE OF AN EMERGENCY
WHILE DRIVING

07
7-3
If You Have a Flat Tire While
Driving
If a tire goes flat while you are driving:
• Take your foot off the accelerator
pedal and let the vehicle slow down
while driving straight ahead. Do not
apply the brakes immediately or
attempt to pull off the road as this
may cause loss of vehicle control
resulting in an accident. When the
vehicle has slowed to such a speed
that it is safe to do so, brake carefully
and pull off the road. Drive off the
road as far as possible and park on
firm, level ground. If you are on a
divided highway, do not park in the
median area between the two traffic
lanes.
• When the vehicle is stopped, press the
hazard warning flasher button, shift
the gear to P (Park), apply the parking
brake, and press the Engine Start/Stop
button to the OFF position.
• Have all passengers get out of the
vehicle. Be sure they all get out on the
side of the vehicle that is away from
traffic.
• When changing a flat tire, follow the
instructions provided later in this
chapter.
IF THE ENGINE WILL NOT
S TA RT
• Be sure to shift the gear to P (Park).
The vehicle starts only when the gear
is in P (Park).
• This vehicle does not have a regular
12V battery that needs periodic
replacement. It is lithium ion polymer
type integrated into the HEV high
voltage battery. The vehicle has a
12V battery protection system that
cuts 12V battery from vehicle draw
to prevent full discharge. If vehicle
will not start, first try pressing the
12V Battery Reset switch (left side of
the steering wheel near the fuel door
open switch) to reconnect the 12V
battery, but you must start vehicle
within 15 seconds of pressing the 12V
Battery Reset switch. After starting
the vehicle (
indicator ON ),
operate the vehicle safely outdoors in
ready mode stopped and/or drive it
for 30 minutes total to charge the 12V
battery fully.
• Check the fuel level and add fuel if
necessary.
If the vehicle still does not start, call
an authorized HYUNDAI dealer for
assistance.
NOTICE
Push or pull starting the vehicle may
cause the catalytic converter to
overload which can lead to damage to
the emission control system.

Emergency situations
7-4
Before Jump Starting
This vehicle does not have a regular 12V
battery that needs periodic replacement.
It is lithium ion polymer type integrated
into the HEV high voltage battery. The
vehicle has a 12V battery protection
system that cuts 12V battery from vehicle
draw to prevent full discharge.
Using the 12V battery reset switch
ODN8HQ019028
1. Press the 12V Battery Reset switch to
reconnect the 12V battery.
2. Start the vehicle within 15 seconds of
pressing the 12V Battery Reset switch.
3. After starting the vehicle
( indicator on), operate the vehicle
safely outdoors in ready mode
stopped and/or drive it for 30 minutes
total to charge the 12V battery fully. If you do not start the vehicle
immediately after pressing the 12V
Battery Reset switch, the power of 12V
battery is automatically disconnected
after few seconds to save the 12V battery
from additional discharge. If the 12V
battery is disconnected prior to starting
the vehicle, press the 12V Battery Reset
switch again and then immediately start
the vehicle as explained.
Repeated use of the 12V Battery Reset
switch without a sufficient engine
ON cycle (30 Min+) may cause over
discharge of the 12V battery, which will
prevent the vehicle from starting. If the
12V battery is over discharged to a point
that the reset does not work, try to jump-
start the vehicle.
Information
After starting the vehicle
( indicator on), the 12V battery is being
charged whether the engine is running or
not. Although there is no engine sound, it
is unnecessary to depress the accelerator
pedal.
The following items may need to be reset
after the battery has been discharged or
the battery has been disconnected.
See chapter 4 and 5 for:
• Power Windows
• Trip Computer
• Climate Control System
• Clock
• Audio System
• Sunroof
IF THE 12 VOLT BATTERY IS DISCHARGED

07
7-5
NOTICE
External power source using 12V battery
The use of external power accessories
may reduce performance and function
of the vehicle. Especially, the use of
dash cameras may shut off the power of
the vehicle prior to the dash camera’s
automatic shut-down.
If the power of the vehicle is shut off,
start the vehicle as explained. (refer to
“Using the 12V Battery Reset Switch”)
Jump Starting
In the event vehicle still does not have a
functional 12V battery (check if interior
lights will not turn on) then you can try
a jump start to the engine compartment
jumper terminals using a 12V booster
pack or jumper cables from another
vehicle’s 12V battery according to the
following instructions.
CAUTION
Jump starting can be dangerous if
done incorrectly. Follow the jump
starting procedure in this section to
avoid serious injury or damage to
your vehicle. If in doubt about how to
properly jump start your vehicle, we
strongly recommend that you have a
service technician or towing service do
it for you.
1. Position the vehicles close enough
that the jumper cables will reach, but
do not allow the vehicles to touch.
Avoid fans or any moving parts in the
engine compartment at all times, even
when the vehicles are turned off.
2. Turn off all electrical devices such as
radios, lights, air conditioning, etc.
Put the vehicles in P (Park) and set the
parking brake. Turn both vehicles OFF.
ODN8H070022N
3. Connect the jumper cables in
the exact sequence shown in the
illustration. First connect one jumper
cable to the red, positive (+) jumper
terminal of your vehicle (1).
4. Connect the other end of the jumper
cable to the red, positive (+) battery/
jumper terminal of the assisting
vehicle (2).
5. Connect the second jumper cable to
the black, negative (-) battery/chassis
ground of the assisting vehicle (3).
6. Connect the other end of the second
jumper cable to the black, negative (-)
chassis ground of your vehicle (4).
Do not allow the jumper cables to
contact anything except the correct
battery or jumper terminals or the
correct ground. Do not lean over the
battery when making connections.

Emergency situations
7-6
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7. Press the 12V Battery Reset switch.
8. Start the engine of the assisting
vehicle and let it run for a few
minutes.
9. Start your vehicle as soon as
possible. After starting the vehicle
(
indicator on), operate the vehicle
safely outdoors in ready mode
stopped and/or drive it for 30 minutes
total to charge the 12V battery fully.
If your vehicle will not start after a few
attempts, it probably requires servicing.
In this event please seek qualified
assistance. If the cause of your battery
discharging is not apparent, have your
vehicle checked by an authorized
HYUNDAI dealer.
Disconnect the jumper cables in the
exact reverse order you connected them:
1. Disconnect the jumper cable from the
black, negative (-) chassis ground of
your vehicle (4).
2. Disconnect the other end of the
jumper cable from the black, negative
(-) battery/chassis ground of the
assisting vehicle (3).
3. Disconnect the second jumper cable
from the red, positive (+) battery/
jumper terminal of the assisting
vehicle (2).
4. Disconnect the other end of the
jumper cable from the red, positive (+)
jumper terminal of your vehicle (1).
Information
The voltage range of the charger should be
13.3~14V and its current range should be
less than 60A. (13.8V is recommended).
CAUTION
• The use of an improper charger
with a voltage and current range
higher than specified may cause
overheating and damage to the 12V
battery.
• The use of an incorrect charger will
lead to a power shut-off to save the
12V battery. Stop using the incorrect
charger once the power of the
vehicle is shut off.
Information
An inappropriately disposed battery can be harmful to
the environment and human
health. Dispose of the battery
according to your local law(s) or
regulations.
NOTICE
To prevent damage to your vehicle:
• Only use a 12-volt power supply
(battery or jumper system) to jump
start your vehicle.
• Do not attempt to jump start your
vehicle by push-starting.
CAUTION
Do not jump start another vehicle with
your hybrid vehicle. Jump starting
another vehicle will damage the
hybrid vehicle’s 12 volt battery (lithium
polymer type).

07
7-7
If your temperature gauge indicates
overheating, you experience a loss of
power, or hear loud pinging or knocking,
the engine may be overheating. If this
happens, you should:
1. Pull off the road and stop as soon as it
is safe to do so.
2. Shift the gear to P (Park) and set the
parking brake
3. Turn off the air conditioner.
4. When the coolant or hot steams
gush out of the reservoir, stop the
engine and we recommend that
you call an authorized HYUNDAI
dealer for assistance. If the coolant
does not flow out, leave the engine
compartment opened, while running
the engine. Check the coolant
temperature gauge on the instrument
cluster and turn off the engine to
make sure the coolant temperature is
sufficiently cooled down.
5. Cool down the engine sufficiently
and check the coolant level. When it
is insufficient, check its connection
with the radiator, the heater hose,
and the water pump for any leakage.
When there is no leakage, add the
coolant. However, if the problems
persists, such as the coolant leakages,
the cooling-fan malfunction or the
water pump drive belt damages,
immediately stop the engine, and
have your vehicle checked by an
authorized HYUNDAI dealer.
• You should mix antifreeze and water in
a proper ratio to make coolant. If the
antifreeze ratio is too high or low, it
may cause overheating due to the lack
of cooling function.
(Refer to the Mix Ratio in “Checking
the coolant level” in chapter 8.)
• If overheating happens repeatedly,
we recommend that you have
your vehicle to be checked by an
authorized HYUNDAI dealer.
WARNING
While the engine is running, keep hands, clothing and tools
away from the moving parts
such as the cooling fan and
drive belt to prevent serious
injury.
IF THE ENGINE OVERHEATS