2004 SUBARU IMPREZA WRX check engine

4-1
4
Climate control
Ventilator ....................................................... 4-2 Air flow selection .............................................. 4-2
Center and side ventilators .............................. 4-3
Manual climate control system (if equipped) 4-4 Control panel ..................................................... 4-4
Heater operation ............................................... 4-6
Air conditioner operation (if equipped) .......... 4-9
Semi-automatic climate control system (if equipped) ............................................... 4-11Control panel ..................................................... 4-11
Operating method ............................................. 4-14
Temperature sensors ....................................... 4-18
Operating tips for heater and air conditioner 4-19 Cleaning ventilation grille ................................ 4-19
Efficient cooling after parking in direct sunlight ........................................................... 4-19
Lubrication oil circulation in the refrigerant
circuit .............................................................. 4-19
Checking air conditioning system before summer season .............................................. 4-19
Cooling and dehumidifying in high humidity and low temperature weather conditions .... 4-20
Air conditioner compressor shut-off when
engine is heavily loaded ................................ 4-20
Refrigerant for your climate control system .. 4-20
Air filtration system (if equipped) ................ 4-20 Replacing an air filter ....................................... 4-21

4-20
Climate control
!
Cooling and dehumidifying in high hu-
midity and low temperature weather
conditions
Under certain weather conditions (high relative humid-
ity, low temperatures, etc.) a small amount of water
vapor emission from the air outlets may be noticed.
This condition is normal and does not indicate any
problem with the air conditioning system. ! Air conditioner compressor shut-off
when engine is heavily loaded
To improve acceleration and gas mileage, the air con-
ditioner compressor is designed to temporarily shut off
during air conditioner operation whenever the acceler-
ator is fully depressed such as during rapid accelera-
tion 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
refrigerant are not covered under warranty.Air filtration system (if equipped)
If your vehicle’s air conditioning system is equipped
with an air filtration system, replace the filter element
according to the replacement schedule shown below.
This schedule should be followed to maintain the fil-
ter’s dust collection ability. Under extremely dusty con-
ditions, the filter should be replaced more frequently. It
is recommended that you have your filter checked or
replaced by your SUBARU dealer. For replacement,
use only a genuine SUBARU air filter kit.
Replacement schedule: Every 12 months or 7,500 miles (12,000 km) whichev-
er comes first

7-1
7
Starting and operating
F uel .. ... ... ... .. ... ... ... ... .. ... ... ... ... ... .. ... ... ... ... .. ... ... 7-2
F uel re quire ments ..................... ..................... ... 7-2
Fuel filler lid and cap ........................................ 7-4
State emission testing (U.S. only) ............... 7-7
Preparing to drive ......................................... 7-9
Starting the engine ....................................... 7-9 Manual transmission vehicle ........................... 7-9
Automatic transmission vehicle ...................... 7-10
Starting the engine during cold weather below −4 °F ( −20 °C) ......................................... 7-10
Starting a flooded engine ................................. 7-11
Stopping the engine ..................................... 7-11
Manual transmission – 6 speed (WRX-STi) 7-12 Selecting reverse gear ...................................... 7-12
Shifting speeds ................................................. 7-13
Driving tips ........................................................ 7-14
Manual transmission – 5 speed (except WRX-STi) ...................................... 7-15Shifting speeds ................................................. 7-15
Driving tips ........................................................ 7-17
Driver’s Control Center Differential (DCCD) (WRX-STi) ..................................... 7-18Auto mode ......................................................... 7-18
Manual mode ..................................................... 7-19
Temporary release ............................................ 7-21
Automatic transmission ............................... 7-21 Selector lever for automatic transmission ..... 7-22
Shift lock release .............................................. 7-26
Limited slip differential (LSD) (if equipped) 7-27 Power steering .............................................. 7-28
Braking ........................................................... 7-28
Braking tips ....................................................... 7-28
Brake system .................................................... 7-29
Disc brake pad wear warning indicators ........ 7-29
ABS (Anti-lock Brake System) ..................... 7-30 ABS system self-check .................................... 7-30
ABS warning light ............................................. 7-31
Electronic Brake Force Distribution (EBD) system ........................................................ 7-32Steps to take if EBD system fails .................... 7-33
Parking your vehicle ..................................... 7-34 Parking brake .................................................... 7-34
Parking tips ....................................................... 7-35
Cruise control ................................................ 7-37 To set cruise control ........................................ 7-37
To temporarily cancel the cruise control ....... 7-39
To turn off the cruise control ........................... 7-40
To change the cruising speed ......................... 7-40

7-6
Starting and operating
weather, which may cause injury.
3. Stop filling the tank after the fuel filler pump auto-
matically stops. Do not add any more fuel.
4. Put the cap back on, turn it clockwise until you hear
a clicking noise. Be certain not to catch the tether un-
der the cap while tightening.
5. Close the fuel filler lid completely.
If you spill any fuel on the painted surface, rinse it off
immediately. Otherwise, the painted surface could be
damaged.
NOTE
If the fuel filler cap is not tightened until it clicks or
if the tether is caught under the cap, the CHECK
ENGINE warning light may come on. Refer to the
“Warning and indicator lights” section located in
chapter 3.
" Never add any cleaning agents to the fuel
tank. The addition of a cleaning agent may
cause damage to the fuel system." Make sure that the cap is tightened until it
clicks to prevent fuel spillage in the event of an
accident. "
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 emis-
sion control system might be damaged.

7-8
Starting and operating
inspection program or its contractors or licens-ees.
The EPA has issued regulations for inspecting the On-
Board Diagnostic (OBD) system as part of the state
emissions inspection. The OBD system is designed to
detect engine and transmission problems that might
cause vehicle emissions to exceed allowable limits.
These inspections apply to all 1996 model year and
newer passenger cars and light trucks. Several states
plus the District of Columbia have opted to start the
OBD system inspection prior to the required EPA reg-
ulation effective date of January 1, 2002. Other states
will add OBD system inspection in 2002. " The inspection of the OBD system consists of a vi-
sual operational check of the “ CHECK ENGINE” warn-
ing light/malfunction indicator lamp (MIL) and an ex-
amination of the OBD system with an electronic scan
tool while the engine is running." A vehicle passes
the OBD system inspection if
proper the “ CHECK ENGINE ” warning light/MIL illumi-
nation is observed, there is no stored diagnostic trou-
ble 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 ENGINE”
warning light/MIL illuminated. " A state emission inspection may reject (not pass or
fail) a vehicle if the number of OBD system readinessmonitors “ Not Ready ” is greater than three. 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.

7-9
Starting and operating
– CONTINUED –
Preparing to drive
You should perform the following checks and adjust-
ments 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 inflation.
3. Look under the vehicle for any sign of leaks.
4. Check that the hood, trunk and rear gate are fully
closed.
5. Check the adjustment of the seat.
6. Check the adjustment of the inside and outside mir-
rors.
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” po-sition.
9. Check the gauges, indicator and warning lights af-
ter starting the engine.
NOTE
Engine oil, engine coolant, brake fluid, washer flu-
id and other fluid levels should be checked daily,
weekly or at fuel stops.
Starting the engine
Do not operate the starter motor continuously
for more than ten seconds. If the engine fails to
start after operating the starter for five to ten
seconds, wait for ten seconds or more before
trying again.
! Manual transmission vehicle
1. Apply the parking brake.
2. Turn off unnecessary lights and accessories.
3. Press the clutch pedal to the floor and shift the shift
lever into neutral. Hold the clutch pedal to the floor
while starting the engine.
The starter motor will only operate when the clutch
pedal is pressed fully to the floor.
4. Turn the ignition switch to the “ON” position and
check the operation of the warning and indicator lights.
Refer to the “Warning and indicator lights” section (chapter 3).
5. Turn the ignition switch to the “START” position
without depressing the accelerator pedal. Release
the key immediately after the engine has started.

7-10
Starting and operating
If the engine does not start within ten seconds, wait a
while and then turn the ignition switch to the “START”
position again while depressing the accelerator pedal
half way down.
6. Confirm that all warning and indicator lights have
gone off after the engine has started. The fuel injection
system automatically lowers the idle speed as the en-
gine warms up. !
Automatic transmission vehicle
1. Apply the parking brake.
2. Turn off unnecessary lights and accessories.
3. Shift the selector lever to the “P” or “N” position
(preferably “P” position).
The starter motor will only operate when the select le-
ver is at the “P” or “N” position.
4. Turn the ignition switch to the “ON” position and
check the operation of the warning and indicator lights.
Refer to the “Warning and indicator lights” section
(chapter 3).
5. Turn the ignition switch to the “START” position
without depressing the accelerator pedal. Release
the key immediately after the engine has started.
If the engine does not start within ten seconds, wait a
while and then turn the ignition switch to the “START”
position again while depressing the accelerator pedal half way down.
6. Confirm that all warning and indicator lights have
gone out after the engine has started. The fuel injec-
tion system automatically lowers the idle speed as the
engine warms up.
While the engine is warming up, make sure that the
selector lever is at the “P” or “N” position and that the
parking brake is applied.
If you restart the engine while the vehicle is
moving, shift the selector lever into the “N” po-
sition. Do not attempt to place the selector lever
of a moving vehicle into the “P” position.
! Starting the engine during cold weath- er below −4 °F ( −20 °C)
If the engine is difficult to start using the normal meth-
od (without depressing the accelerator pedal), turn the
ignition switch to the “START” position while slightly
depressing the accelerator pedal.

7-29
Starting and operating
– CONTINUED –
!Braking when a tire is punctured
Do not depress the brake pedal suddenly when a tire
is punctured. This could cause a loss of control of the
vehicle. Keep driving straight ahead while gradually
reducing speed. Then slowly pull off the road to a safe
place. ! Brake system
! Two separate circuits
Your vehicle has two separate circuit brake systems.
Each circuit works diagonally across the vehicle. If one
circuit of the brake system should fail, the other half of
the system still works. If one circuit fails, the brake
pedal will go down much closer to the floor than usual
and you will need to press it down much harder. And a
much longer distance will be needed to stop the vehi- cle. ! Brake booster
The brake booster uses engine manifold vacuum to
assist braking force. Do not turn off the engine while
driving because that will turn off the brake booster, re-
sulting in poor braking power.
The brakes will continue to work even when the brake
booster completely stops functioning. If this happens,
however, you will have to push the pedal much harder than normal and the braking distance will increase. !
Disc brake pad wear warning indica- tors
The disc brake pad wear warning indicators on the
disc brakes give a warning noise when the brake pads
are worn.
If a squeaking or scraping noise is heard from the disc
brakes while braking, immediately have your vehicle
checked by your SUBARU dealer.
HS7012BA