2003 SUBARU IMPREZA WRX check engine

Maintenance and service
11-4
Always be very careful to avoid injury when
working on the vehicle. Remember that some of the materials in the vehicle may be hazard-
ous if improperly used or handled, for exam-ple, battery acid. Your vehicle should only be serviced by per-
sons fully competent to do so. Serious per-sonal injury may result to persons not experi-enced in servicing vehicles. Always use the proper tools and make cer-
tain 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 airbag system or seatbelt pretensioner sys-tem, or attempt to take its connectors apart,as that may activate the system or it can ren-der it inoperative. The wiring and connectorsof these systems are yellow for easy identifi-cation. NEVER use a circuit tester for these wiring. If your SRS airbag or seatbelt pretensionerneeds service, consult your nearest SUBARU
dealer.
Before checking or servicing in the
engine 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 theengine 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

Maintenance and service
11-5
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suddenly even when the engine is stopped. When you do checking or servicing in the engine compartment whilethe engine is running
A running engine can be dangerous. Keep your fingers, hands, clothing, hair and toolsaway from the cooling fan, belts and any other
moving engine parts. Removing rings,watches and ties is advisable. Engine hood
To open the hood:
1. Pull the hood release knob under the instrument panel.

Maintenance and service
11-10
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 theengine.
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 i on its top ap-
pearing as shown in the illustration.
1) Notch
2) Upper level 3) Lower level
4) Front of vehicle
4. Pull out the dipstick again and check the oil level on it. If it is below the lower level, add oil to bring thelevel up to the upper level.
CAUTION
Use only engine oil with the recommended
grade and viscosity. Be careful not to spill engine oil when ad-
ding it. If oil touches the exhaust pipe, it may
cause a bad smell, smoke, and/or a fire.

Maintenance and service
11-11
– CONTINUED –
If you check the oil level just after stopping the en-
gine, 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
engine oil level reading may be in a range betweenthe upper level and the notch mark. This is caused
by thermal expansion of the engine oil.
To prevent overfilling the engine oil, do not add any
additional oil above the upper level when the engineis cold. 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
frequently 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 theengine.
3. Remove the oil filler cap.
1) Drain plug
4. Drain out the engine oil by removing the drain
plug while the engine is still warm. The used oil
should be drained into an appropriate container and
disposed of properly.
WARNING
Be careful not to burn yourself with hot en- gine oil.
5. Wipe the seating surface of the drain plug with a
clean cloth and tighten it securely with a new seal-

Maintenance and service
11-12
ing washer after the oil has completely drained out.
1) Oil filter
6. Remove the oil filter with an oil filter wrench.
7. Before installing a new oil filter, apply a thin coatof engine oil to the seal.
8. Clean the rubber seal seating area of the lower
crank case and install the oil filter by hand turning.
Be careful not to twist or damage the seal.
9. Tighten it approximately two-thirds of a turn after the seal makes contact with the lower crank case.
CAUTION
Never over tighten the oil filter because that can result in an oil leak.
10. Pour engine oil through the filler neck.
Oil capacity (guideline): Non-turbo models: 4.2 US qt (4.0 liters, 3.5 Imp qt)
Turbo models: 4.8 US qt (4.5 liters, 4.0 Imp qt)
The oil quantity indicated above is only guideline.
The necessary quantity of oil depends on the quan- tity of oil that has been drained. The quantity of
drained oil differs slightly depending on the temper-
ature of the oil and the time the oil is left flowing out.
After refilling the engine with oil, therefore, you must
the dipstick to confirm that the level is correct.
11. Start the engine and make sure that no oil leaks
appear around the filter ’s rubber seal and drain
plug.
12. Run the engine until it reaches the normal oper-
ating temperature. Then stop the engine and wait a
few minutes to allow the oil drain back. Check the oil
level again and if necessary, add more engine oil.

Maintenance and service
11-16
Do not splash the engine coolant over
painted parts. The alcohol contained in the en- gine coolant may damage the paint surface.
Cooling fan, hose and connections
Your vehicle employs an electric cooling fan which
is thermostatically controlled to operate when the
engine coolant reaches a specific temperature.If the radiator cooling fan does not operate even
when the engine coolant temperature gauge ex-
ceeds the normal operating range, the cooling fan
circuit may be defective. Check the fuse and re-
place it if necessary. If the fuse is not blown, havethe cooling system checked by your SUBARU deal-
er.
If frequent addition of coolant is necessary, there
may be a leak in the engine cooling system. It is rec-
ommended that the cooling system and connectionsbe checked for leaks, damage, or looseness.
Engine coolant
Checking the coolant level
1) “FULL” level mark
2) “LOW” level mark
Check the coolant level at each fuel stop.
1. Check the coolant level on the outside of the res-ervoir while the engine is cool.
2. If the level is close to or lower than the “LOW”
level mark, add coolant up to the “FULL” level mark.
If the reserve tank is empty, remove the radiator cap
and refill as required.

Maintenance and service
11-17
– CONTINUED –
1) Rubber gaskets
3. After refilling the reserve tank and the radiator, re- install the caps and check that the rubber gaskets
inside the radiator cap are in the proper position.
CAUTION
Be careful not to spill engine coolant when
adding it. If coolant touches the exhaust pipe, it may cause a bad smell, smoke, and/or a fire. Do not splash the engine coolant over
painted parts. The alcohol contained in the en-gine coolant may damage the paint surface.
Changing the coolant
1) Drain plug
Change the engine coolant using the following pro-
cedures according to the maintenance schedule.
1. Remove the under cover.
2. Place a proper container under the drain plugand loosen the drain plug.
3. Loosen the radiator cap to drain the coolant from
the radiator. Then drain the coolant from the reserve
tank. Tighten the drain plug securely.

Maintenance and service
11-26
Turbo model
Check the oil level monthly.
1. Park the vehicle on a level surface and stop theengine.
2. Pull out the dipstick, wipe it clean, and insert itagain.1) Upper level 2) Lower level
3. Pull out the dipstick again and check the oil level
on it. If it is below the lower level, add oil through thedipstick hole to bring the level up to the upper level. Recommended grade and viscosity
Each oil manufacturer has its own base oils and ad-
ditives. Never use different brands together.
Oil grade: API classification GL-5