🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX / WRX STI

Year:

2012

👋 Introduction

Positioning:

The Subaru Impreza WRX and WRX STI are performance-oriented compact sports sedans/hatchbacks, known for their turbocharged engines, all-wheel-drive systems, and rally racing heritage. This manual caters to owners and technicians seeking in-depth knowledge for maintaining and repairing these specialized vehicles.

Competitors:

Competes with vehicles like the Mitsubishi Lancer Evolution, Volkswagen Golf GTI, Ford Focus ST, and similar performance compacts. The WRX STI, in particular, stands out with its advanced symmetrical all-wheel-drive and driver-controlled center differential.

Vehicle Highlights:

Turbocharged boxer engines, Symmetrical All-Wheel Drive, sport-tuned suspension, performance brakes, driver-focused interiors, distinctive styling.

📋 Manual Details

Coverage Scope:

Comprehensive repair and service for 2012 Subaru Impreza WRX and WRX STI models.

Estimated Pages:

Over 2000 pages (typical for factory service manuals of this era).

Type:

Factory Service Manual (FSM) / Workshop Manual

Language:

English

Format:

Digital Download (PDF)

📖 Manual Coverage

Engine Mechanical:

Engine assembly, disassembly, inspection, repair, lubrication, cooling, fuel delivery, emissions control.

Engine Performance:

Engine control systems (ECU, sensors, actuators), ignition system, turbocharger system (WRX/STI specific).

Transmission Drivetrain:

Manual transmission (6-speed for STI, 5-speed for WRX), clutch system, all-wheel-drive system (center differential, rear differential), driveshafts, axles.

Suspension Steering:

Front and rear suspension components (struts, springs, control arms, sway bars), steering system (rack and pinion, power steering), wheel alignment specifications.

Brakes:

Brake system components (master cylinder, brake lines, calipers, pads, rotors), ABS system, parking brake.

Electrical System:

Battery, charging system (alternator), starting system, lighting, horn, wipers, power windows, power locks, instrument cluster, fuses, relays.

Climate Control:

HVAC system (heating, ventilation, air conditioning), refrigerant, components, operation, troubleshooting.

Body Interior:

Body panel removal/installation, interior trim, seats, airbags, doors, windows, glass, exterior trim.

Diagnostics Troubleshooting:

Diagnostic trouble codes (DTCs), symptom-based troubleshooting, wiring diagrams, component testing procedures.

Routine Maintenance:

Oil and filter changes, fluid checks and top-offs, air filter replacement, spark plug replacement, brake pad/rotor replacement, tire rotation.

Major Repairs:

Engine overhaul, transmission overhaul, clutch replacement, differential service, suspension component replacement, brake system overhaul, turbocharger service.

Electrical Diagnostics:

Wiring diagram interpretation, circuit testing, sensor troubleshooting, ECU diagnosis.

Bodywork:

Panel alignment, door/window adjustment, interior component removal and installation, basic body repair procedures.

Engine Timing:

Detailed procedures for checking and adjusting engine timing, including belt/chain replacement where applicable (though EJ engines use timing belts).

Fuel System Diagnosis:

Troubleshooting fuel injectors, fuel pump, fuel pressure regulator, and EVAP system. Includes fuel pressure specifications.

Ignition System Diagnosis:

Testing ignition coils, spark plugs, crankshaft position sensor, camshaft position sensor, and ignition timing verification.

Cooling System Repair:

Radiator service, water pump replacement, thermostat testing and replacement, heater core diagnosis and replacement.

Turbocharger System Service:

Detailed breakdown of the turbocharger, wastegate, blow-off valve, intercooler system, and related piping. Includes diagnostic flowcharts for boost leaks and performance issues.

Drivetrain Component Rebuild:

Instructions for rebuilding manual transmissions, front and rear differentials, and servicing the AWD coupling system. Includes detailed torque specifications and bearing preloads.

ABS And Vsc Diagnosis:

Troubleshooting ABS wheel speed sensors, ABS control module, yaw rate sensor, steering angle sensor, and VDC system faults. Includes bleeding procedures for the ABS modulator.

Airbag System Service:

Procedures for airbag module replacement, SRS warning light diagnosis, and safety precautions when working on the Supplemental Restraint System.

Depth:

Extremely high. Covers everything from basic fluid changes to complete engine and transmission rebuilds, including detailed diagnostic procedures and specifications.

Diagnostic Tools:

References diagnostic trouble codes (DTCs) and often refers to Subaru's proprietary diagnostic tool (e.g., Subaru Select Monitor - SSM) or compatible OBD-II scanners for advanced diagnostics.

📊 Manual Specifications

File Type:

PDF

Searchability:

Searchable text for quick information retrieval.

Indexing:

Well-indexed with a table of contents and often an index for easy navigation.

Resolution:

High resolution, suitable for printing individual pages or the entire manual.

Binding:

Not applicable (digital format).

Paper Type:

Not applicable (digital format).

⚙️ Engine Specifications

Engine Code:

EJ255

Configuration:

2.5L Turbocharged Boxer 4-cylinder

Horsepower:

265 hp @ 6000 rpm

Torque:

244 lb-ft @ 4000 rpm

Engine Code:

EJ257

Configuration:

2.5L Turbocharged Boxer 4-cylinder (high-performance variant)

Horsepower:

305 hp @ 6000 rpm

Torque:

290 lb-ft @ 4000 rpm

Fuel Delivery:

Sequential multi-point fuel injection (MPI)

Fuel Type:

Premium Unleaded Gasoline (91 octane or higher recommended)

🔧 Transmission

Type:

5-speed Manual Transmission

Type:

6-speed Manual Transmission

Drivetrain:

Symmetrical All-Wheel Drive (AWD) with front helical limited-slip differential, rear mechanical limited-slip differential (WRX) and Driver Controlled Center Differential (DCCD) with front and rear limited-slip differentials (WRX STI).

📐 Dimensions

Length:

Approximately 179.9 inches

Width:

Approximately 70.7 inches

Height:

Approximately 58.1 inches

Wheelbase:

Approximately 104.0 inches

Curb Weight Wrx:

Approximately 3,310 - 3,350 lbs

Curb Weight Sti:

Approximately 3,370 - 3,440 lbs

🛡️ Safety Features

NHTSA Overall:

Not specifically rated for 2012 WRX/STI, but previous generations generally performed well in crash tests.

Active Safety:

Brake Assist (BA), Electronic Brake-force Distribution (EBD), Traction Control System (TCS), Vehicle Dynamics Control (VDC), Subaru's Symmetrical All-Wheel Drive system.

Passive Safety:

Advanced front airbags, front side-impact airbags, side curtain airbags, driver's knee airbag, front seatbelt pretensioners, energy-absorbing steering column.

💡 Technology Features

Infotainment System:

Basic audio system with CD player, MP3 capability, auxiliary input. Optional navigation system available on some trims. Limited smartphone integration compared to modern vehicles.

Driver Assistance Features:

Primarily focused on the advanced AWD system and VDC for stability control. No significant semi-autonomous driver assistance features like adaptive cruise control or lane keeping assist.

Connectivity Options:

Auxiliary audio input jack. Bluetooth hands-free calling may be available on higher trims, but streaming audio functionality is limited.

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles or 6 months, whichever comes first (severe driving conditions); 7,500 miles or 12 months (normal driving conditions). Always consult the manual for specific recommendations.

Engine Oil Type Wrx:

SAE 5W-30 Synthetic (API Service SM or SN)

Engine Oil Type Sti:

SAE 5W-30 Synthetic (API Service SM or SN) - Note: some STI owners opt for thicker oils like 10W-40 depending on usage.

Coolant Type:

Subaru Super Coolant (Blue) or equivalent (50/50 mix with distilled water)

Transmission Fluid Wrx 5Mt:

Subaru Extra-S Gear Oil (API GL-4) or equivalent

Transmission Fluid Sti 6Mt:

Subaru Extra-S Gear Oil (API GL-4) or equivalent

Front Rear Diff Fluid:

Subaru Extra-S Gear Oil (API GL-5) or equivalent

Ej Engine Wear:

Ring land failures on EJ25 engines, particularly when subjected to aggressive driving or tuning without proper supporting modifications. This manual details inspection procedures and correct assembly practices.

Clutch Wear:

Clutch can wear prematurely with hard use. Manual covers clutch replacement procedures and specifications.

Turbocharger Maintenance:

Proper warm-up and cool-down procedures are critical for turbo longevity. Manual details turbocharger inspection and service.

📚 Vehicle History

Heritage:

Subaru has a long-standing reputation for building reliable, practical vehicles with a focus on safety and capability, particularly its All-Wheel Drive technology, which originated from its aerospace division.

Generation:

This represents the first model year of the third generation Impreza WRX/STI (GH/GR/GV chassis code) which transitioned to a more conventional sedan body style (though a hatchback was also available in some markets). Previous generations were more rally-car-like with a distinct hatchback dominance.

Manufacturing Location:

Gunma Plant, Japan

🏆 Awards & Recognition

Automotive Press Awards:

While specific awards for the 2012 model year may vary, Subaru Impreza WRX and WRX STI models have consistently received accolades from automotive publications for their performance, handling, and rally-inspired driving dynamics over many years.