2021 HYUNDAI SONATA HYBRID engine

Foreword
1-2
INTRODUCTION
Congratulations, and thank you for choosing HYUNDAI. We are pleased to welcome
you to the growing number of discerning people who drive HYUNDAIs. We are very
proud of the advanced engineering and high-quality construction of each HYUNDAI
we build.
Your Owner’s Manual will introduce you to the features and operation of your new
HYUNDAI. To become familiar with your new HYUNDAI, so that you can fully enjoy it,
read this Owner’s Manual carefully before driving your new vehicle.
This manual contains important safety information and instructions intended to
familiarize you with your vehicle’s controls and safety features so you can safely
operate your vehicle.
This manual also contains information on maintenance designed to enhance safe
operation of the vehicle. It is recommended that all service and maintenance on your
car be performed by an authorized HYUNDAI dealer. HYUNDAI dealers are prepared
to provide high-quality service, maintenance and any other assistance that may be
required.
This Owner’s Manual should be considered a permanent part of your vehicle, and
should be kept in the vehicle so you can refer to it at any time. The manual should stay
with the vehicle if you sell it to provide the next owner with important operating, safety
and maintenance information.
HYUNDAI MOTOR AMERICA
CAUTION
Severe engine and transmission damage may result from the use of poor quality
fuels and lubricants that do not meet HYUNDAI specifications. You must always use
high quality fuels and lubricants that meet the specifications listed on Page 2-11 in
the Vehicle Specifications section of the Owner’s Manual.
Copyright 2020 HYUNDAI Motor America. All rights reserved. No part of this
publication may be reproduced, stored in any retrieval system or transmitted in
any form or by any means without the prior written permission of HYUNDAI Motor
America.

01
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1. What are HYUNDAI Genuine Parts?
HYUNDAI Genuine Parts are the
same parts used by HYUNDAI Motor
Company to manufacture vehicles.
They are designed and tested for the
optimum safety, performance, and
reliability for our customers.2. Why Hyundai Genuine Parts?
HYUNDAI Genuine Parts are
engineered and built to meet rigid
manufacturing requirements.
Damage caused by using imitation,
counterfeit or used salvage parts is
not covered under the HYUNDAI New
Vehicle Limited Warranty or any other
HYUNDAI warranty.
In addition, any damage to or failure
of HYUNDAI Genuine Parts caused
by the installation or failure of an
imitation, counterfeit or used salvage
part is not covered by any HYUNDAI
Warranty.
3. How can you tell if you are
purchasing HYUNDAI Genuine Parts?
Look for the HYUNDAI Genuine Parts
Logo on the package (see below).
HYUNDAI Genuine Parts exported
to the U.S. are packaged with labels
written only in English.
HYUNDAI Genuine Parts are only
sold through authorized HYUNDAI
Dealerships.
GUIDE TO HYUNDAI GENUINE PARTS

01
1-5
Your new vehicle is designed to obtain
maximum performance with UNLEADED
FUEL, as well as minimize exhaust
emissions and spark plug fouling.
Your new vehicle is designed to use only
unleaded fuel having an octane number
((R+M)/2) of 87 (Research Octane
Number 91) or higher. (Do not use
methanol blended fuels)
NOTICE
To prevent damage to the engine and
engine components, never add any fuel
system cleaning agents to the fuel tank
other than what has been specified.
Consult an authorized HYUNDAI dealer
for additional information.
WARNING
• Do not “top off” after the nozzle
automatically shuts off when
refueling.
• Always check that the fuel cap is
installed securely to prevent fuel
spillage in the event of an accident.
FUEL REQUIREMENTS
Throughout this manual DANGER,
WARNING, CAUTION, NOTICE and the
SAFETY ALERT SYMBOL will be used.
This is the safety alert symbol. It is used to alert you to potential
physical injury hazards. Obey
all safety messages that follow
this symbol to avoid possible
injury or death. The safety alert
symbol precedes the signal
words DANGER, WARNING and
CAUTION.
DANGER
DANGER indicates a hazardous
situation which, if not avoided, will
result in death or serious injury.
WARNING
WARNING indicates a hazardous
situation which, if not avoided, could
result in death or serious injury.
CAUTION
CAUTION indicates a hazardous
situation which, if not avoided, could
result in minor or moderate injury.
NOTICE
NOTICE indicates a situation which,
if not avoided, could result in vehicle
damage.

Foreword
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Gasoline containing alcohol or
methanol
Gasohol, a mixture of gasoline and
ethanol (also known as grain alcohol) are
being marketed along with or instead
of leaded or unleaded gasoline. For
example, “E15” is a gasohol comprised of
15% ethanol and 85% gasoline.
Do not use gasohol containing more than
15% ethanol, and do not use gasoline or
gasohol containing any methanol. Either
of these fuels may cause drivability
problems and damage to the fuel
system, engine control system and
emission control system.
Discontinue using gasohol of any kind if
drivability problems occur.
“E85” fuel is an alternative fuel
comprised of 85 percent ethanol and 15
percent gasoline, and is manufactured
exclusively for use in Flexible Fuel
Vehicles. “E85” is not compatible with
your vehicle. Use of “E85” may result in
poor engine performance and damage
to your vehicle’s engine and fuel system.
HYUNDAI recommends that customers
do not use fuel with an ethanol content
exceeding 15 percent.
NOTICE
To prevent damage to your vehicle’s
engine and fuel system:
• Never use gasohol which contains
methanol.
• Never use gasohol containing more
than 15% ethanol.
• Never use leaded fuel or leaded
gasohol.
• Never use “E85” fuel.
Your New Vehicle Limited Warranty
does not cover damage to the fuel
system or any performance problems
caused by the use of “E85” fuel.
Using Fuel Additives (except
Detergent Fuel Additives)
Using fuel additives such as:
- Silicone fuel additive
-Ferrocene (iron-based) fuel additive
-Other metallic-based fuel additives
may result in cylinder misfire, poor
acceleration, engine stalling, damage
to the catalyst, or abnormal corrosion,
and may cause damage to the engine
resulting in a reduction in the overall life
of the powertrain.
- The Malfunction Indicator Lamp (MIL)
may illuminate.
NOTICE
Damage to the fuel system or
performance problem caused by the
use of these fuels or fuel additives may
not be covered by your New Vehicle
Limited Warranty.
Gasoline containing MMT
Some gasoline contains harmful
manganese-based fuel additives such
as MMT (Methylcyclopentadienyl
Manganese Tricarbonyl).
HYUNDAI does not recommend the use
of gasoline containing MMT.
This type of fuel can reduce vehicle
performance and affect your emission
control system.
The malfunction indicator lamp on the
cluster may come on.

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Detergent Fuel Additives
HYUNDAI recommends that you use
good quality gasolines treated with
detergent additives such as TOP TIER
Detergent Gasoline, which help prevent
deposit formation in the engine. These
gasolines will help the engine run
cleaner and enhance performance of
the Emission Control System. For more
information on TOP TIER Detergent
Gasoline, please go to the website (www.
toptiergas.com ).
For customers who do not use TOP Tier
Detergent Gasoline regularly, and have
problems starting or the engine does
not run smoothly, detergent-based
fuel additives that you can purchase
separately may be added to the gasoline.
If TOP TIER Detergent Gasoline is
not available, one bottle of additive
added to the fuel tank according to the
maintenance schedule is recommended
(refer to the Maintenance Schedule in
chapter 8).
Additives are available from your
authorized HYUNDAI dealer along with
information on how to use them. Do not
mix other additives.
Operation in foreign countries
If you are going to drive your vehicle in
another country, be sure to:
• Observe all regulations regarding
registration and insurance.
• Determine that acceptable fuel is
available. •
This vehicle should not be modified.
Modification of your vehicle could
affect its performance, safety or
durability and may even violate
governmental safety and emissions
regulations.
In addition, damage or performance
problems resulting from any
modification may not be covered
under warranty.
• If you use unauthorized electronic
devices, it may cause the vehicle to
operate abnormally, wire damage,
battery discharge and fire. For your
safety, do not use unauthorized
electronic devices.
VEHICLE BREAK-IN
PROCESS
By following a few simple precautions for
the first 600 miles (1,000 km) you may
add to the performance, economy and
life of your vehicle.
• Do not race the engine.
• While driving, keep your engine speed
(rpm, or revolutions per minute)
between 2,000 rpm and 4,000 rpm.
• Do not maintain a single speed for
long periods of time, either fast or
slow. Varying engine speed is needed
to properly break-in the engine.
• Avoid hard stops, except in
emergencies, to allow the brakes to
seat properly.
VEHICLE MODIFICATIONS

Foreword
1-8
VEHICLE DATA COLLECTION
AND EVENT DATA
RECORDERS
This vehicle is equipped with an event
data recorder (EDR). The main purpose
of an EDR is to record, in certain crash
or near crash-like situations, such as
an air bag deployment or hitting a
road obstacle, data that will assist in
understanding how a vehicle’s systems
performed. The EDR is designed to
record data related to vehicle dynamics
and safety systems for a short period of
time, typically 30 seconds or less. The
EDR in this vehicle is designed to record
such data as:
• How various systems in your vehicle
were operating;
• Whether or not the driver and
passenger safety belts were buckled/
fastened;
• How far (if at all) the driver was
depressing the accelerator and/or
brake pedal; and,
• How fast the vehicle was traveling.
These data can help provide a better
understanding of the circumstances in
which crashes and injuries occur. NOTE:
EDR data are recorded by your vehicle
only if a non-trivial crash situation
occurs; no data is recorded by the EDR
under normal driving conditions and
no personal data (e.g., name, gender,
age, and crash location) are recorded.
However, other parties, such as law
enforcement, could combine the
EDR data with the type of personally
identifying data routinely acquired
during a crash investigation.
To read data recorded by an EDR,
special equipment is required, and
access to the vehicle or the EDR is
needed. In addition to the vehicle
manufacturer, other parties, such as
law enforcement, that have the special
equipment, can read the information if
they have access to the vehicle or the
EDR.
WARNING
CALIFORNIA PROPOSITION 65
WARNING
Items contained in motor vehicles or
emitted from them are known to the
State of California to cause cancer and
birth defects or reproductive harm.
These include:
• Gasoline and its vapors
• Engine exhaust
• Used engine oil
• Interior passenger compartment
components and materials
• Component parts which are subject
to heat and wear
In addition, battery posts, terminals and
related accessories contain lead, lead
compounds and other chemicals known
to the State of California to cause
cancer and reproductive harm.
For more information go to
https://www.p65warnings.ca.gov/
passenger-vehicle

1-12
Foreword
HEV (HYBRID ELECTRIC VEHICLE) SYSTEM
The HYUNDAI Hybrid Electric Vehicle (HEV) uses both the gasoline engine and the
electric motor for power. The electric motor is run by a high-voltage HEV battery.
Depending on the driving conditions, the HEV computer selectively operates between
the engine and the electric motor or even both at the same time.
Fuel efficiency increases when the engine is at idle, or when the vehicle is driven by the
electric motor with the HEV battery.
The HEV battery charge must be maintained, so at times the engine will come on even
at idle to act as a generator. Charging also occurs when decelerating or by regenerative
braking.
Electric motorElectric motorElectric motor + EngineElectric motor + Engine EngineEngineChargingCharging Engine OFFEngine OFF
Startup/Low speed cruise Acceleration High speed cruiseDecelerationStop
ODN8H069105

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Starting the Vehicle
Vehicles with smart key system
1. Carry the smart key or leave it inside
the vehicle.
2. Make sure the parking brake is firmly
applied.
3. Make sure the shift button is in P
(Park). With the shift button in N
(Neutral), you cannot start the vehicle.
4. Depress the brake pedal.
5. Press the Engine Start/Stop button.
If the hybrid system starts, the “”
indicator will come on.
Whether the engine is cold or warm, it
should be started without depressing
the accelerator.
After following the start procedures,
“
” indicator on the instrument
cluster will turn on. For more details,
please check chapter 6.
ECONOMICAL and SAFE OPERATION of
Hybrid system
• Drive smoothly. Accelerate at a
moderate rate and maintain a steady
cruising speed. Do not make “jack-
rabbit” starts. Do not race between
stoplights.
• Avoid heavy traffic whenever possible.
Always maintain a safe distance
from other vehicles so you can
avoid unnecessary braking. This also
reduces brake wear.
• The regenerative brake generates
energy when the vehicle decelerates.
• When the hybrid battery power is
low, the hybrid system automatically
recharges the hybrid battery.
• When the engine is running with the
shift button in N (Neutral), the hybrid
system cannot generate electricity.
The hybrid battery cannot recharge
with the shift button in N (Neutral).
Information
In the hybrid system, the engine
automatically runs and stops. When
the hybrid system operates, the “
”
indicator is illuminated.
In the following situation, the engine may
operate automatically.
- When the engine is ready to run
-When the hybrid battery is being
charged
-Depending on the temperature
condition of the hybrid battery
Special Features
Hybrid vehicles sound different than
gasoline engine vehicles. When the
hybrid system operates, you may hear
a sound from the hybrid battery system
behind the rear seat. If you apply the
accelerator pedal rapidly, you may hear
an unconventional sound. When you
apply the brake pedal, you may hear
a sound from the regenerative brake
system. When the hybrid system is
turned off or on, you may hear a sound
in the engine compartment. If you
depress the brake pedal repeatedly
when the hybrid system is turned on,
you may hear a sound in the engine
compartment. None of these sounds
indicate a problem. These are normal
characteristics of hybrid vehicles.
If any of following occur, it’s a normal
condition if you hear a motor sound in
the engine compartment:
-After turning off the hybrid system,
the brake pedal is released.
-When the hybrid system is turned off,
the brake pedal is applied.
-When the driver door is opened.
DRIVING THE HYBRID VEHICLE