open gas tank Hyundai Sonata 2004 Owner's Manual

1- 2 FEATURES OF YOUR HYUNDAI
CAUTION:Your Hyundai's New Vehicle Limited War-
ranty may not cover damage to the fuel
system and any performance problems that
are caused by the use of fuels containing
methanol or fuels containing MTBE (Methyl
Tertiary Butyl Ether) over 15.0% vol. (Oxy-
gen Content 2.7% weight.)B010B01A-AATWhat About Gasohol?
Gasohol (a mixture of 90% unleaded gasoline
and 10% ethanol or grain alcohol) may be used
in your Hyundai. However, if your engine devel-
ops driveability problems, the use of 100%
unleaded gasoline is recommended. Fuels with
unspecified quantities of alcohol, or alcohols
other than ethanol, should not be used.
B010A02A-AATFUEL RECOMMENDATIONS
Use Unleaded Gasoline
Unleaded gasoline with a Pump Octane
Rating of 87 (Research Octane Number 91)
or higher must be used in your Hyundai.
If leaded gasoline is used, it will cause the
catalytic converter to become ineffective and
the emission control system to malfunction.
This can also result in increased maintenance
expense.
To avoid accidental use of leaded fuel, the larger
nozzle used with leaded gasoline at service
stations cannot be inserted into the fuel tank
opening of your Hyundai.
B010C01A-AAT
Use of MTBE
Hyundai recommends that fuels containing
MTBE (Methyl Tertiary Butyl Ether) over 15.0%
vol. (Oxygen Content 2.7% weight) should not
be used in your Hyundai.
Fuel containing MTBE over 15.0% vol. (Oxygen
Content 2.7% weight) may reduce vehicle per-
formance and produce vapor lock or hard
starting.
B010D01A-AATDo Not Use Methanol
Fuels containing methanol (wood alcohol) should
not be used in your Hyundai. This type of fuel
can reduce vehicle performance and damage
components of the fuel system.
B010E01A-AATGasolines for Cleaner AirTo help contribute to cleaner air, Hyundai rec-
ommends that you use gasolines treated with
detergent additives, which help prevent deposit
formation in the engine. These gasolines will
help the engine run cleaner and the Emission
Control System performance.
!
CAUTION:o Do not "TOP-OFF" after the first nozzle
shut off when refueling.
o The fuel cap must be tightened at least
3 clicks, otherwise " " light may
illuminate.
B010A03Y-1
UNLEADED
FUEL ONLY
!

7- 2 EMISSION CONTROL SYSTEMS
H010E01Y-AATEGR System (If installed)
This system helps reduce nitrogen oxides by
recirculating a part of the exhaust gas into the
engine, thereby reducing cylinder combustion
temperature, which results in lower output of
oxides of nitrogen.
H010D01A-AAT3. Exhaust Emission Control System
The Exhaust Emission Control System is a
highly effective system which controls exhaust
emissions while maintaining good vehicle
performace.
H010B01A-AAT1. Crankcase Emission Control
System
The positive crankcase ventilation system is
employed to prevent air pollution caused by
blow-by gases being emitted from the crank-
case. This system supplies filtered air to the
crankcase through the air intake hose. Inside
the crankcase, the fresh air mixes with blow-by
gases, which then pass through the PCV valve
and into the induction system.
H010A01L-AATEMISSION CONTROL SYSTEM
Your Hyundai is equipped with an emission
control system to meet all requirements of the
U.S. Environmental Protection Agency or Cali-
fornia Air Resources Board.
There are three emission control systems which
are as follows.
(1) Crankcase emission control system
(2) Evaporative emission control system
(3) Exhaust emission control system
In order to assure the proper function of the
emission control systems, it is recommended
that you have your car inspected and main-
tained by an authorized Hyundai dealer in ac-
cordance with the maintenance schedule in this
manual.
Caution for Inspection and Maintenance
Test (2.7 V6 Vehicle with Traction Control
System)
o To prevent the vehicle from misfiring
during dynamometer testing, discon-
nect the ABS connector located on the
left side of the engine compartment.
o For more information, see shop manual
(BR-67, Wheel Speed Sensor)
H010C02S-AAT
2. Evaporative Emission Control
(Including ORVR: Onboard Refueling
Vapor Recovery) System
The Evaporative Emission Control System is
designed to prevent fuel vapors from escaping
into the atmosphere.
(The ORVR system is designed to allow the
vapors from the fuel tank to be loaded into a
canister while refueling at the gas station, pre-
venting the escape of fuel vapors into the
atmosphere.)
Canister
Fuel vapors generated inside the fuel tank are
absorbed and stored in the onboard canister.
When the engine is running, the fuel vapors
absorbed in the canister are drawn into the
surge tank through the purge control solenoid
valve.
Purge Control Solenoid Valve (PCSV)
The purge control solenoid valve is controlled
by the Engine Control Module (ECM); when the
engine coolant temperature is low during idling,
the PCSV closes so that evaporated fuel is not
taken into the engine. After the engine warms-
up during ordinary driving, the PCSV opens to
introduce evaporated fuel to the engine.