2004 SUBARU IMPREZA WRX check engine

8-29
Driving tips
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Trailer towing
Your car is designed and intended to be used primarily
as a passenger-carrying vehicle. Towing a trailer puts
additional loads on your car’s engine, drivetrain,
brakes, tires and suspension and has an adverse ef-
fect on fuel economy.
If you do decide to tow a trailer, your safety and satis-
faction depend upon proper use of correct equipment
and cautious operation of your vehicle. Seek the ad-
vice of your SUBARU dealer to assist you in purchas-
ing a hitch and other necessary towing equipment ap-
propriate for your vehicle. In addition, be sure to follow
the instructions on correct installation and use provid-
ed by the trailer and other towing equipment manufac-
turers.
SUBARU assumes no responsibility for injuries or ve-
hicle damage that result from trailer towing equipment,
or from any errors or omissions in the instructions ac-
companying such equipment or for your failure to fol-
low the proper instructions. !Warranties and maintenance
SUBARU warranties do not apply to vehicle damage
or malfunction caused by trailer towing. If you use your
vehicle to tow a trailer, more frequent maintenance will
be required due to the additional load. (Refer to “Main- tenance schedule under severe driving conditions” in
the “Warranty and Maintenance Booklet”.)
Under no circumstances should a trailer be towed with
a new vehicle or a vehicle with any new powertrain
component (engine, transmission, differential, wheel
bearings, etc.) for the first 1,000 miles (1,600 km) of
driving. !
Maximum load limits
Never exceed the maximum load limits ex-
plained below. Exceeding the maximum load
limits could cause personal injury and/or vehi-
cle damage.
"Adequate size trailer brakes are required
when the trailer and its cargo exceed 1,000 lbs
(453 kg) total weight." Before towing a trailer, check the trailer total
weight, GVW, GAWs and tongue load. Make
sure the load and its distribution in your vehicle

9-17
In case of emergency
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Confirm that the cooling fan is turning. If the fan is not
turning, immediately turn the engine off and contact
your authorized dealer for repair.
3. After the engine coolant temperature has dropped, turn off the engine.
If the temperature gauge stays at the overheated
zone, turn the engine off.
4. After the engine has fully cooled down, check the
coolant level in the reserve tank.
If the coolant level is below the “LOW” mark, add cool-
ant up to the “FULL” mark.
5. If there is no coolant in the reserve tank, add cool-
ant to the reserve tank. Then remove the radiator cap
and fill the radiator with coolant.
If you remove the radiator cap from a hot radiator, first
wrap a thick cloth around the radiator cap, then turn
the cap counterclockwise slowly without pressing
down until it stops. Release the pressure from the ra-
diator. After the pressure has been fully released, re-
move the cap by pressing down and turning it.Towing
If towing is necessary, it is best done by your SUBARU
dealer or a commercial towing service. Observe the
following procedures for safety.
Never tow AWD vehicles (both AT and MT) with
the front wheels raised off the ground while the
rear wheels are on the ground, or with the rear
wheels raised off the ground while the front
wheels are on the ground. This will cause the
vehicle to spin away due to the operation or de-
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9-21
In case of emergency
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!Towing with all wheels on the ground
1. Check the transmission and differential oil levels
and add oil to bring it to the upper level if necessary.
2. Release the parking brake and put the transmis-
sion in neutral.
3. The ignition switch should be in the “ACC” position
while the vehicle is being towed.
4. Take up slack in the towline slowly to prevent dam-
age to the vehicle.
" Never turn the ignition switch to the “LOCK”
position while the vehicle is being towed be- cause the steering wheel and the direction of
the wheels will be locked. "
Remember that the brake booster and power
steering do not function when the engine is not
running. Because the engine is turned off, it will
take greater effort to operate the brake pedal
and steering wheel.
" If transmission failure occurs, transport your
vehicle on a flat-bed truck. " Do not run the engine while being towed us-
ing this method. Transmission damage could
result if the vehicle is towed with the engine
running. " For vehicles with automatic transmission,
the traveling speed must be limited to less than
20 mph (30 km/h) and the traveling distance to
less than 31 miles (50 km). For greater speeds
and distances, transport your vehicle on a flat-
bed truck.
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11 - 1
11
Maintenance and service
Maintenance schedule ................................. 11-3
Maintenance precautions ............................ 11-3 Before checking or servicing in the engine compartment .................................................. 11-4
When you do checking or servicing in the engine compartment while the engine is
running ............................................................ 11-5
Engine hood .................................................. 11-5
Engine compartment overview ................... 11-8 2.5 liter model .................................................... 11-8
2.0 liter (Turbo) model ...................................... 11-9
2.5 liter (Turbo) model ...................................... 11-10
Engine oil ...................................................... 11-11 Checking the oil level ....................................... 11-11
Changing the oil and oil filter .......................... 11-12
Recommended grade and viscosity ................ 11-16
Recommended grade and viscosity under severe driving conditions .............................. 11-18
Synthetic oil ....................................................... 11-18
Cooling system ............................................. 11-18 Cooling fan, hose and connections ................ 11-19
Engine coolant .................................................. 11-19
Air cleaner element ...................................... 11-23 Replacing the air cleaner element ................... 11-23
Spark plugs ................................................... 11-26 Recommended spark plugs ............................. 11-27
Drive belts ..................................................... 11-27
Manual transmission oil ............................... 11-28 Checking the oil level ....................................... 11-28
Recommended grade and viscosity ................ 11-30 Automatic transmission fluid ...................... 11-31
Checking the fluid level .................................... 11-31
Recommended fluid ......................................... 11-32
Front differential gear oil (AT vehicles) ...... 11-33 Checking the oil level ....................................... 11-33
Recommended grade and viscosity ............... 11-33
Rear differential gear oil ............................... 11-34 Checking the gear oil level .............................. 11-34
Recommended grade and viscosity ............... 11-35
Power steering fluid ...................................... 11-36 Checking the fluid level .................................... 11-36
Recommended fluid ......................................... 11-37
Brake fluid ..................................................... 11-37 Checking the fluid level .................................... 11-37
Recommended brake fluid ............................... 11-38
Clutch fluid (MT vehicles) ............................ 11-38 Checking the fluid level .................................... 11-38
Recommended clutch fluid .............................. 11-39
Brake booster ................................................ 11-40
Brake pedal .................................................... 11-40 Checking the brake pedal free play ................ 11-40
Checking the brake pedal reserve distance ... 11-41
Clutch pedal (MT vehicles) ........................... 11-41 Checking the clutch function .......................... 11-41
Checking the clutch pedal free play ............... 11-42
Replacement of brake pad and lining ......... 11-42 Breaking-in of new brake pads and linings .... 11-43
Parking brake stroke .................................... 11-44
Tires and wheels ........................................... 11-44

11 - 4
Maintenance and service
the materials in the vehicle may be hazardous if
improperly used or handled, for example, bat- tery acid."
Your vehicle should only be serviced by per-
sons fully competent to do so. Serious person-
al injury may result to persons not experienced
in servicing vehicles. " Always use the proper tools and make certain
that they are well maintained. " Never get under the vehicle supported only
by a jack. Always use a safety stands to sup-
port the vehicle. " Never keep the engine running in a poorly
ventilated area, such as a garage or other
closed areas. " Do not smoke or allow open flames around
the fuel or battery. This will cause a fire. " Because the fuel system is under pressure,
replacement of the fuel filter should be per-
formed only by your SUBARU dealer. " Wear adequate eye protection to guard
against getting oil or fluids in your eyes. If
something does get in your eyes, thoroughly
wash them out with clean water. " Do not tamper with the wiring of the SRS air-
bag system or seatbelt pretensioner system, or
attempt to take its connectors apart, as that may activate the system or it can render it inop-
erative. The wiring and connectors of these
systems are yellow for easy identification. NEV-
ER use a circuit tester for these wiring.
If your SRS airbag or seatbelt pretensioner
needs service, consult your nearest SUBARU
dealer.
! Before checking or servicing in the en-
gine compartment
"Always stop the engine and set the parking
brake firmly to prevent the vehicle from mov-
ing. " Always let the engine cool down. Engine
parts become very hot when the engine is run-
ning and remain hot for some time after the en-
gine is stopped. " Do not spill engine oil, engine coolant, brake
fluid or any other fluid on hot engine compo-
nents. This may cause a fire. " Always remove the key from the ignition
switch. When the ignition switch is in the “ON”
position, the cooling fan may operate suddenly

11 - 5
Maintenance and service
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even when the engine is stopped.
! When you do checking or servicing in
the engine compartment while the en-
gine is running
A running engine can be dangerous. Keep your
fingers, hands, clothing, hair and tools away
from the cooling fan, belts and any other mov-
ing engine parts. Removing rings, watches and
ties is advisable.
Engine hood
0
To open the hood:
1. If the wiper blades are lifted off the windshield, re-
turn them to their original positions.
2. Pull the hood release knob under the instrument
panel.
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11-11
Maintenance and service
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Engine oil !Checking the oil level
Check the engine oil level at each fuel stop.
1. Park the vehicle on a level surface and stop the en-
gine.
2. Pull out the dipstick, wipe it clean, and insert it
again.
3. Be sure the dipstick is correctly inserted until it
stops with the graphic symbol on its top appear-
ing as shown in the illustration. 2.5-liter turbo models
1) Notch
2) Upper level
3) Lower level
HGB056BA
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11 - 1 2
Maintenance and service
2.5-liter and 2.0-liter turbo models
1) Notch
2) Upper level
3) Lower level
4. Pull out the dipstick again and check the oil level on
it. If it is below the lower level, add oil to bring the level
up to the upper level.
" Use only engine oil with the recommended
grade and viscosity. " Be careful not to spill engine oil when adding
it. If oil touches the exhaust pipe, it may cause
a bad smell, smoke, and/or a fire.
If you check the oil level just after stopping the engine,
wait a few minutes for the oil to drain back into the oil
pan before checking the level.
Just after driving or while the engine is warm, the en-
gine oil level reading may be in a range between the
upper level and the notch mark. This is caused by ther-
mal expansion of the engine oil.
To prevent overfilling the engine oil, do not add any
additional oil above the upper level when the engine iscold. ! Changing the oil and oil filter
Change the oil and oil filter according to the mainte-
nance schedule in the “Warranty and Maintenance Booklet”.
The engine oil and oil filter must be changed more fre-
quently than listed in the maintenance schedule when
driving on dusty roads, when short trips are frequently
made, or when driving in extremely cold whether.
1. Warm up the engine by letting the engine idle for
about 10 minutes to ease draining the engine oil.
2. Park the vehicle on a level surface and stop the en-
gine.
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