2006 SUBARU IMPREZA service

4-12 Climate control
any problem with the air conditioning sys-
tem.
Air conditioner compressor
shut-off when engine is
heavily loaded
To improve acceleration and gas mileage,
the air conditioner compressor is de-
signed to temporarily shut off during air
conditioner operation whenever the accel-
erator is fully depressed such as during
rapid acceleration or when driving on a
steep upgrade.
Refrigerant for your climate
control system
Your air conditioner uses ozone friendly
refrigerant HFC134a. Therefore, the
method of adding, changing or checking
the refrigerant is different from the method
for CFC12 (Freon). Consult your
SUBARU dealer for service. Repairs
needed as a result of using the wrong re-
frigerant are not covered under warranty.
Air filtration system
If your vehicle ’s air conditioning system is
equipped with an air filtration system, re-
place the filter element according to the
replacement schedule shown in the fol-
lowing. This schedule should be followed
to maintain the filter ’s dust collection abili-
ty. Under extremely dusty conditions, the
filter should be replaced more frequently.
It is recommended that you have your fil-
ter checked or replaced by your SUBARU
dealer. For replacement, use only a genu-
ine SUBARU air filter kit.
Replacement schedule:
Every 12 months or 7,500 miles (12,000
km) whichever comes first
Replacing an air filter
1. Remove the glove box.1) Open the glove box.
2) Remove the nine screws and the one
clip securing the glove box.
3) Disconnect the glove box light con-
nector.
400604

4-14 Climate control
1) Service label
2) Caution label
8. LABEL installation
1) Fill out the information on the service
label (small).
2) Attach the service label to the driver
side door pillar and the caution label to
the driver side end of the instrument
panel.
NOTE
The filter can influence the air condi-
tioning, heating and defroster perfor-
mance if not properly maintained.
Contact your dealer if the following
occurs, even if it is not yet time to
change the filter:
Reduction of the air flow through
the vents.
2 1
400609
Windshield gets easily fogged or
misted.

7-2 Starting and operating
Starting and operatingFuel
Fuel requirements
2.5-liter non-turbo models
The 2.5-liter non-turbo engine is designed
to operate using unleaded gasoline with
an octane rating of 87 AKI or higher.
WRX
The 2.5-liter turbo engine is designed to
operate using premium unleaded gasoline
with an octane rating of 91 AKI or higher.
If premium unleaded gasoline is not avail-
able, regular unleaded gasoline with an
octane rating of 87 AKI or higher may be
temporarily used. For optimum engine
performance and driveability, it is required
that you use premium grade unleaded
gasoline.
NOTE
Be sure to use premium unleaded gas-
oline of 91 AKI or higher for WRX. If
other gasoline (lower than 91 AKI) is
used, knocking, reduced output and poor accelerator response will result.
WRX-STI
The 2.5-liter turbo engine is designed to
operate using super-premium unleaded
gasoline with an octane rating of 93 AKI or
higher. If super-premium unleaded gaso-
line with an octane rating of 93 AKI or
higher is not available, premium unleaded
gasoline with an octane rating of 91 AKI or
higher may be temporarily used. For opti-
mum engine performance and driveability,
it is required that you use super-premium
grade unleaded gasoline with an octane
rating of 93 AKI or higher.
NOTE
Be sure to use super-premium unlead-
ed gasoline of 93 AKI or higher for
WRX-STI. If other gasoline (lower than
93 AKI) is used, knocking, reduced out-
put and poor accelerator response will
result.
Fuel octane rating
This octane rating is the average of the
Research Octane and Motor Octane num-
bers and is commonly referred to as the
Anti Knock Index (AKI).
Using a gasoline with a lower octane rat-
ing can cause persistent and heavy
knocking, which can damage the engine.
Do not be concerned if your vehicle some- times knocks lightly when you drive up a
hill or when you accelerate. See your
dealer or a qualified service technician if
you use a fuel with the specified octane
rating and your vehicle knocks heavily or
persistently.
Unleaded gasoline
The neck of the fuel filler pipe is designed
to accept only an unleaded gasoline filler
nozzle. Under no circumstances should
leaded gasoline be used because it will
damage the emission control system and
may impair driveability and fuel economy.
Gasoline for California-certified LEV
Your vehicle was certified to California ’s
low emission vehicle (LEV) standards as
indicated on the underhood tune-up label,
it is designed to optimize engine and
emission performance with gasoline that
meets the clean burning low-sulfur Califor-
nia gasoline specifications. If you live in
any other state than California, your vehi-
cle will operate on gasoline meeting Fed-
eral specifications. Gasoline sold outside
California is permitted to have higher sul-
fur levels, which may affect the perfor-
mance of your vehicle ’s catalytic convert-
er and may produce a sulfur exhaust odor
or smell. SUBARU recommends that you
try a different brand of unleaded gasoline
having lower sulfur to determine if the
Use of a fuel which is low in quality
or use of an inappropriate fuel addi-
tive may cause engine damage.

Starting and operating 7-3
– CONTINUED –
problem is fuel related before returning
your vehicle to an authorized dealer for
service.
MMT
Some gasoline contains an octane-en-
hancing additive called MMT (Methylcy-
clopentadienyl Manganese Tricarbonyl). If
you use such fuels, your emission control
system performance may deteriorate and
the CHECK ENGINE warning light/Mal-
function indicator lamp may turn on. If this
happens, return to your authorized
SUBARU Dealer for service. If it is deter-
mined that the condition is caused by the
type of fuel used, repairs may not be cov-
ered by your warranty.
Gasoline for cleaner air
Your use of gasoline with detergent addi-
tives will help prevent deposits from form-
ing in your engine and fuel system. This
helps keep your engine in tune and your
emission control system working properly,
and is a way of doing your part for cleaner
air. If you continuously use a high quality
fuel with the proper detergent and other
additives, you should never need to add
any fuel system cleaning agents to your
fuel tank.
Many gasolines are now blended with ma-
terials called oxygenates. Use of these fu- els can also help keep the air cleaner. Ox-
ygenated blend fuels, such as MTBE (Me-
thyl Tertiary Butyl ether) or ethanol (ethyl
or grain alcohol) may be used in your ve-
hicle, but should contain no more than
15% MTBE or 10% ethanol for the proper
operation of your SUBARU.
In addition, some gasoline suppliers are
now producing reformulated gasolines,
which are designed to reduce vehicle
emissions. SUBARU approves the use of
reformulated gasoline.
If you are not sure what the fuel contains,
you should ask your service station oper-
ators if their gasolines contain detergents
and oxygenates and if they have been re-
formulated to reduce vehicle emissions.
As additional guidance, only use fuels
suited for your vehicle as explained in the
following.
Fuel should be unleaded and have an
octane rating no lower than that specified
in this manual.
Methanol (methyl or wood alcohol) is
sometimes mixed with unleaded gasoline.
Methanol can be used in your vehicle
ONLY if it does not exceed 5% of the fuel
mixture AND if it is accompanied by suffi-
cient quantities of the proper cosolvents
and corrosion inhibitors required to pre- vent damage to the fuel system. Do not
use fuel containing methanol
EXCEPT un-
der these conditions.
If undesirable driveability problems are
experienced and you suspect they may be
fuel related, try a different brand of gaso-
line before seeking service at your
SUBARU dealer.
Fuel system damage or driveability
problems which result from the use of im-
proper fuel are not covered under the
SUBARU Limited Warranty.
Do not let fuel spill on the exterior
surfaces of the vehicle. Fuels con-
taining alcohol may cause paint
damage, which is not covered under
the SUBARU Limited Warranty.

Starting and operating 7-5
– CONTINUED –
light comes on. Engine misfires as a re-
sult of an empty tank could cause dam-
age to the engine.
State emission testing (U.S.
only)
At state inspection time, remember to
tell your inspection or service station
in advance not to place your Subaru
AWD vehicle on a two-wheel dyna-
mometer. Otherwise, serious transmis-
sion damage will result.
Some states have started using dyna-
mometers in their state inspection pro-
grams in order to meet their obligation un-
der federal law to implement stricter vehi-
cle emission standards to reduce air pollu-
tion from vehicles. A dynamometer is a
treadmill or roller-like testing device that
allows your vehicle
’s wheels to turn while
the vehicle remains in one place. Depend-
ing on the severity of a state ’s air pollution
problems, the states must adopt either a“ basic ” or “enhanced ” vehicle emission in-
spection test. Normally, a portion of the
basic emission test consists of an emis-
sion inspector inserting an analyzer probe
into the exhaust pipe of an idling vehicle
for a short period of time. States with more
severe air pollution problems are required
to adopt an enhanced vehicle emission
test. This test simulates actual driving
conditions on a dynamometer and permits
more accurate measurement of tailpipe emitted pollution than the basic emission
test.
The U.S. Environmental Protection Agen-
cy (EPA) and states using two-wheel dy-
namometers in their emission testing pro-
grams have
EXEMPTED Subaru AWD
vehicles from the portion of the testing
program that involves a two-wheel dyna-
mometer.
There are some states that use four-wheel
dynamometers in their testing programs.
When properly used, that equipment will
not damage an AWD Subaru vehicle.
Under no circumstances should the rear
wheels be jacked off the ground, nor
should the driveshaft be disconnected for
state emission testing.
Never add any cleaning agents to
the fuel tank. The addition of a
cleaning agent may cause dam-
age to the fuel system.
Make sure that the cap is tight-
ened until it clicks to prevent fuel
spillage in the event of an acci-
dent.
Do not let fuel spill on the exterior
surfaces of the vehicle.
Fuels may cause paint damage,
which is not covered under the
SUBARU Limited Warranty.
Always use a genuine SUBARU
fuel filler cap. If you use the wrong
cap, it may not fit or have proper
venting, and your fuel tank and
emission control system might be
damaged.
Testing of an All-Wheel Drive vehi-
cle must NEVER be performed on a
single two-wheel dynamometer. At-
tempting to do so will result in un-
controlled vehicle movement and
may cause an accident or injuries to
persons nearby.

7-6 Starting and operating
The EPA has issued regulations for in-
specting the On-Board Diagnostic (OBD)
system as part of the state emissions in-
spection. The OBD system is designed to
detect engine and transmission problems
that might cause vehicle emissions to ex-
ceed allowable limits. These inspections
apply to all 1996 model year and newer
passenger cars and light trucks. Over 30
states plus the District of Columbia have
implemented the OBD system inspection.
The inspection of the OBD system con-
sists of a visual operational check of the “ CHECK ENGINE ” warning light/malfunc-
tion indicator lamp (MIL) and an examina-
tion of the OBD system with an electronic
scan tool while the engine is running.
A vehicle passes the OBD system in-
spection if proper the “CHECK ENGINE ”
warning light/MIL illumination is observed,
there is no stored diagnostic trouble
codes, and the OBD system readiness
monitors are complete.
A vehicle fails the OBD inspection if the
“ CHECK ENGINE ” warning light/MIL is
not properly operating or there is one or
more diagnostic trouble codes stored in
vehicle ’s computer with the “CHECK EN-
GINE ” warning light/MIL illuminated.
A state emission inspection may reject
(not pass or fail) a vehicle if the number of
OBD system readiness monitors “Not
Ready ” is greater than one. Under this
condition, the vehicle operator should be
instructed to drive his/her vehicle for a few
days to set the monitors and return for an
emission re-inspection.
Owners of rejected or failing vehicles
should contact their Subaru Dealer for
service.
Preparing to drive
You should perform the following checks
and adjustments every day before you
start driving.
1. Check that all windows, mirrors, and
lights are clean and unobstructed.
2. Check the appearance and condition of
the tires. Also check tires for proper infla-
tion.
3. Look under the vehicle for any sign of
leaks.
4. Check that the hood, trunk (Sedan)
and rear gate (Wagon) are fully closed.
5. Check the adjustment of the seat.
6. Check the adjustment of the inside and
outside mirrors.
7. Fasten your seatbelt. Check that your
passengers have fastened their seatbelts.
8. Check the operation of the warning and
indicator lights when the ignition switch is
turned to the “ON ” position.
9. Check the gauges, indicator and warn-
ing lights after starting the engine.
NOTE
Engine oil, engine coolant, brake fluid,
washer fluid and other fluid levels
should be checked daily, weekly or at
fuel stops.
Resultant vehicle damage due to im-
proper testing is not covered under
the SUBARU Limited Warranty and
is the responsibility of the state in-
spection program or its contractors
or licensees.

8-4 Driving tips
Periodic inspections
To keep your vehicle in the best condition
at all times, always have the recommend-
ed maintenance services listed in the
maintenance schedule in the “Warranty
and Maintenance Booklet ” performed at
the specified time or mileage intervals.
Driving in foreign countries
When planning to use your vehicle in an-
other country:
Confirm the availability of the correct fu-
el. (Refer to the “Fuel requirements ” sec-
tion in chapter 7.)
Comply with all regulations and require-
ments of each country.
Keep everyone and flammable
materials away from the exhaust
pipe while the engine is running.
The exhaust gas is very hot.

Driving tips 8-25
– CONTINUED –
Side mirrors
After hitching a trailer to your vehicle,
check that the standard side mirrors pro-
vide a good rearward field of view without
significant blind spots. If significant blind
spots occur with the vehicle ’s standard
side mirrors, use towing mirrors that con-
form with Federal, state/province and/or
other applicable regulations.
Trailer lights
Connection of trailer lights to your vehi-
cle ’s electrical system requires modifica-
tions to the vehicle ’s lighting circuit to in-
crease its capacity and accommodate wir-
ing changes. To ensure the trailer lights
are connected properly, please consult
your SUBARU dealer. Check for proper
operation of the turn signals, the brake lights and parking lights each time you
hitch up.
Tires
Make sure that all the tires on your vehicle
are properly inflated to the pressure spec-
ified on the tire placard located on the left
center pillar of your vehicle.
Trailer tire condition, size, load rating and
proper inflation pressure should be in ac-
cordance with the trailer manufacturer ’s
specifications.
In the event your vehicle gets a flat tire
when towing a trailer, ask a commercial
road service to repair the flat tire.
If you carry a regular size spare tire in your
vehicle or trailer as a precaution against
getting a flat tire, be sure that the spare
tire is firmly secured.Trailer towing tips
Before starting out on a trip
Check that the vehicle and vehicle-to-
hitch mounting are in good condition. If
any problems are apparent, do not tow the
800026
Direct splicing or other improper
connection of trailer lights may
damage your vehicle ’s electrical
system and cause a malfunction of
your vehicle ’s lighting system.
Never tow a trailer when the tempo-
rary spare tire is used. The tempo-
rary spare tire is not designed to
sustain the towing load. Use of the
temporary spare tire when towing
can result in failure of the spare tire
and/or less stability of the vehicle.
Never exceed 45 mph (72 km/h)
when towing a trailer in hilly coun-
try on hot days.
When towing a trailer, steering,
stability, stopping distance and
braking performance will be dif-
ferent from normal operation. For
safety ’s sake, you should employ
extra caution when towing a trail-
er and you should never speed.
You should also keep the follow-
ing tips in mind: