Segment:
Performance Compact / Sport Sedan
Target Audience:
Enthusiast drivers, rally fans, owners seeking to maintain or modify their WRX/STI
Key Competitors:
Mitsubishi Lancer Evolution, Volkswagen Golf GTI, Ford Focus RS (later generations)
Performance Focus:
Emphasizes the rally-bred heritage, turbocharged power, and Symmetrical All-Wheel Drive (SAWD) system.
Manual Value:
Provides authoritative information for DIY repairs, modifications, and in-depth understanding of the vehicle's complex systems.
Primary Coverage:
2012 Subaru Impreza WRX and WRX STI
Secondary Coverage:
Potentially applicable to late 2011 and early 2013 models with minor variations
Estimated Page Count:
~2000-3000 pages (typical for comprehensive factory service manuals)
Type:
Factory Service Manual (FSM) / Repair Manual
Format:
Digital Download (PDF)
Powertrain:
Engine (EJ255, EJ257), Turbocharger System, Fuel System, Ignition System, Cooling System, Exhaust System, Transmission (Manual and Automatic variants), Drivetrain (Symmetrical All-Wheel Drive, Differentials, Axles)
Chassis:
Suspension (Front MacPherson Strut, Rear Double Wishbone), Steering System, Brakes (ABS, VDC), Wheels and Tires
Electrical:
Battery, Charging System, Starting System, Lighting, Instrumentation, HVAC Controls, Power Accessories, Engine Control Module (ECM), Body Control Module (BCM), Audio System, SRS (Airbag) System
Body:
Exterior Body Panels, Doors, Windows, Locks, Interior Trim, Seating, Safety Restraints
Maintenance:
Scheduled Maintenance (Oil Changes, Filter Replacements, Fluid Checks), Tune-ups, Inspections
Repair:
Component Removal and Installation, Overhauls, Adjustments, Troubleshooting and Diagnosis
Diagnostics:
OBD-II Diagnostic Codes, Diagnostic Procedures for all major systems, Wiring Diagrams, Component Testing
Depth:
Comprehensive, covering basic maintenance to complete engine and transmission rebuilds. Includes detailed diagnostic trees and specifications for all repair procedures.
Type Wrx:
2.5L DOHC 16-Valve Turbocharged Boxer (EJ255)
Type Sti:
2.5L DOHC 16-Valve Turbocharged Boxer (EJ257)
Horsepower Wrx:
265 hp @ 6000 rpm
Torque Wrx:
244 lb-ft @ 4000 rpm
Horsepower Sti:
305 hp @ 6000 rpm
Torque Sti:
290 lb-ft @ 4000 rpm
Injection Type:
Sequential Multi-Port Fuel Injection (MPI) with Top-Feed Injectors
Fuel Grade Recommendation:
Premium Unleaded (91 Octane or higher)
ECU Type:
Denso ECU (Specific model numbers will be detailed in the manual)
Coolant Type:
Subaru Super Coolant (Blue) or equivalent silicate-free, long-life coolant
Type Wrx:
Mitsubishi TD04L-13T (approx.)
Type Sti:
6-Speed Manual (TY856WB1AA)
Automatic Transmission:
No automatic transmission offered for WRX/STI variants in this model year.
Drivetrain Layout:
Symmetrical All-Wheel Drive (SAWD) with Front Helical Limited-Slip Differential (LSD) and Rear Viscous Coupling LSD (WRX), Front Helical LSD, DCCD (Driver Controlled Center Differential) and Rear Helical LSD (STI)
Manual Gear Oil Spec:
GL-4 75W-90 for front and rear differentials, GL-4 75W-90 for transfer case and transmission (specific Subaru specs may differ, consult manual)
Wheelbase:
103.3 inches (2624 mm)
Length:
173.8 inches (4415 mm)
Width:
70.1 inches (1780 mm)
Height:
57.7 inches (1465 mm)
Wheel Bolt Pattern:
5x114.3 mm (5x4.5 inches)
Wheel Size:
17x8.0 inches (WRX), 18x8.5 inches (STI)
Curb Weight Wrx:
~3200-3300 lbs (1450-1500 kg)
Curb Weight Sti:
~3350-3450 lbs (1520-1565 kg)
NHTSA Front Impact:
5-Star (2012 Model)
IIHS Top Safety Pick:
Top Safety Pick (2012 Model)
Vehicle Dynamics Control:
Standard (VDC) with selectable modes, includes yaw rate, lateral acceleration, and brake pressure sensors.
Traction Control:
Standard
Anti Lock Brakes:
Standard (ABS)
Airbags:
Front, Front Side-Impact, Side Curtain Airbags
Seat Belts:
Pretensioner and Force Limiter Front Seatbelts, Three-Point Rear Seatbelts
Child Seat Anchors:
LATCH System (Lower Anchors and Tethers for CHildren)
Audio System:
Standard AM/FM/CD/MP3 player with auxiliary input. Higher trims may feature Rockford Fosgate audio, Bluetooth, and navigation.
Instrument Cluster:
Features tachometer, speedometer, multi-function display (fuel economy, trip computer, etc.). STI may have additional performance gauges.
Cruise Control:
Standard electronic cruise control.
Bluetooth:
Optional, depending on trim level and audio system.
Oil Change Interval:
Every 3,750 miles or 6 months (severe driving) / 7,500 miles or 12 months (normal driving) - *Consult manual for specific recommendations based on driving conditions.*
Engine Air Filter:
Inspect every 15,000 miles, replace as needed or at ~30,000 miles.
Cabin Air Filter:
Replace every 15,000 miles or 12 months.
Spark Plugs:
Replace approximately every 60,000 miles (for iridium-tipped plugs).
Engine Oil Capacity:
5.8 US quarts (5.5 Liters) with filter change for 2.5L Turbo
Engine Oil Viscosity:
0W-20 or 5W-30 Synthetic (check owner's manual for specific climate recommendations)
Brake Fluid Type:
DOT 3 or DOT 4
Power Steering Fluid Type:
Subaru PS Fluid or ATF Dexron III/Mercon equivalent
Piston Ring Land Cracking:
A known concern in some EJ25 engines, particularly with aggressive tuning or inadequate cooling. Manual provides specifications for checking tolerances.
Clutch Wear:
Can be accelerated by aggressive driving; manual details inspection and replacement procedures.
Turbocharger Oil Feed Line:
Potential for clogging leading to turbo failure; manual may include cleaning/replacement procedures for the banjo bolt screens.
Rally Roots:
Subaru's long and successful history in the World Rally Championship (WRC) with the Impreza platform, influencing the WRX and STI models.
Generation:
Third Generation (GR/GV Hatchback for STI, GE/GH Sedan for WRX, though body styles varied by market and trim)
Manufacturing Plant:
Gunma Manufacturing Plant, Japan
