2012 SUBARU IMPREZA WRX alternator

3-16Instruments and controls
The CHECK ENGINE warning light may
stop blinking and illuminate steadily after
several driving trips. You should have your
vehicle checked by an authorized
SUBARU dealer immediately. &Charge warning light
If this light illuminates when the engine is
running, it may indicate that the charging
system is not working properly.
If the light illuminates while driving or does
not turn off after the engine starts, stop the
engine at the first safe opportunity and
check the alternator belt. If the belt is
loose, broken or if the belt is in good
condition but the light remains illuminated,
contact your nearest SUBARU dealer
immediately. &Oil pressure warning light
If this light illuminates when the engine is
running, it may indicate that the engine oil
pressure is low and the lubricating system
is not working properly.
If the light illuminates while driving or does
not turn off after the engine starts, stop the
engine at the first safe opportunity and
check the engine oil level. If the oil level is
low, add oil immediately. If the engine oil is
at the proper level but the light remains illuminated, contact your nearest
SUBARU dealer immediately.
For details about checking the engine oil
level or adding the engine oil, refer to“
Engine oil ”F 11-8.
CAUTION
Do not operate the engine with the
oil pressure warning light illumi-
nated. This may cause serious en-
gine damage.
& Rear differential oil
temperature warning
light (STI)
CAUTION
Reduce vehicle speed and park the
vehicle in a safe place as soon as
possible if the R.DIFF TEMP light
illuminates. Continued driving with
this light illuminated can damage
the rear differential and other parts
of the powertrain.
If this light illuminates when the engine is
running, it may indicate that the rear
differential oil temperature is too hot.
At this time, the driver ’s control center
differential will automatically cancel the current torque-distribution ratio setting and
adopt its minimum ratio.
If the light illuminates while driving, reduce
vehicle speed and stop the vehicle at the
nearest safe place. Park the vehicle for
several minutes. After the light turns off,
you can start driving.
If the light does not turn off, contact the
nearest SUBARU dealer for service.
NOTE . If the tire pressures are not correct
and/or the tires are not all the same
size and brand, the rear differential will
be heavily loaded when the vehicle is
driven, resulting in an abnormally high
oil temperature.. The rear differential oil will deterio-
rate if its temperature increases en-
ough for the rear differential oil tem-
perature warning light to illuminate. It is
advisable to have the rear differential
oil replaced as soon as possible. & Low tire pressure
warning light (U.S.-spec. models)
When the ignition switch is turned to the “ON ”position, the low tire pressure warn-
ing light will illuminate for approximately 2
seconds to check that the tire pressure

Drive belts
1) Power steering oil pump pulley
2) Front side belt
3) Alternator pulley
4) Air conditioner compressor pulley
5) Rear side belt
6) Crank pulley
A) 22 lbf (98 N, 10 kgf)
CAUTION
The front side belt, which runs in
conjunction with the following com-
ponents, must be used within the
specified deflection. . Power steering oil pump pulley
. Alternator pulley
. Crank pulley Check the deflection of the front
side belt and if there is any loosen-
ess, cracks, wear or unusual noise
on the front side belt, contact your
SUBARU dealer.
Continuing to use the vehicle with
the belt outside of the specification
may cause the engine to malfunc-
tion and the above components tomalfunction.
To check the deflection of the front side
belt, place a straightedge (ruler) across
two adjacent pulleys (alternator pulley and
crank pulley) and apply a force of 22 lbf
(98 N, 10 kgf) midway between the pulleys
by using a spring scale. The belt deflec-
tion should be the amount specified. If the
front side belt is loose, cracked or worn,
contact your SUBARU dealer. in (mm)
Deflection
New belt Used belt
A 0.28
–0.35
(7.0 –9.0) 0.35
–0.43
(9.0 –11.0)
The rear side belt is a stretch-type belt,
therefore the deflection does not need to
be checked. If there are cracks or wear
confirmed on the belts and a squeaking
noise is heard from them, contact your
SUBARU dealer. Manual transmission oil &
Checking the oil level
Except STI
Check the oil level monthly.
1. Park the vehicle on a level surface and
stop the engine.
2. Pull out the level gauge, wipe it clean,
and insert it again. Maintenance and service
11-15
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&Engine
Engine model EJ255
(2.5 L, DOHC, turbo, except STI) EJ257
(2.5 L, DOHC, turbo, STI)
Engine type Horizontally opposed, liquid cooled 4 cylinder, 4-stroke gasoline engine
Displacement cc (cu-in) 2,457 (150)
Bore 6Stroke in (mm) 3.963.1 (99.5 679.0)
Compression ratio 8.4 : 18.2 : 1
Firing order 1
– 3–2– 4
& Electrical system
Battery type and capacity (5HR) MT 12V-48AH (55D23L)
Alternator Turbo models
12V-110A
Spark plugs Turbo models
SILFR6A (NGK)Specifications
12-3
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12-12Specifications
&Fuse panel located in the engine compartment
A) Main fuse Fuse
panel Fuse
rating Circuit
1 30A .ABS unit
. Vehicle Dynamics Con-
trol unit
2 25A .Main fan (cooling fan)
3 10A .Secondary air combina-
tion valve (turbo models)
4 25A .Sub fan (cooling fan)
5 Empty
6 10A .Audio
7 30A .Headlight (low beam)
8 15A .Headlight (high beam)
9 20A .Back-up
10 15A .Horn
11 25A .Rear window defogger
. Mirror heater
12 15A .Fuel pump
13 10A .Automatic transmission
control unit
14 7.5A .Engine control unit
15 15A .Turn and hazard warn-
ing flasher
16 15A .Tail and illumination re-
lay
17 7.5A .Alternator