🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX STI

Year:

2012

Chassis Code:

GVB/GRB (Hatchback), GE/GH (Sedan - though 2012 is primarily hatch focus for WRX STI)

Engine Code:

EJ257

👋 Introduction

Segment:

Performance Compact Sedan/Hatchback (G-segment)

Target Audience:

Enthusiasts, motorsport participants, performance-oriented drivers, professional mechanics.

Key Competitors:

Mitsubishi Lancer Evolution, Volkswagen Golf GTI/R, Ford Focus RS, BMW M235i (depending on market segment and price point).

Performance Focus:

Iconic rally heritage, turbocharged Boxer engine, Symmetrical All-Wheel Drive, performance-tuned suspension.

Dccd:

Driver Controlled Center Differential for adjustable torque distribution.

Chassis Rigidity:

Enhanced chassis design for improved handling and responsiveness.

📋 Manual Details

Primary Coverage:

All mechanical and electrical systems, bodywork, and diagnostics for the 2012 Subaru Impreza WRX STI.

Estimated Pages:

1500-2000+ (typical for a comprehensive workshop manual of this era and complexity)

Type:

Workshop Service Manual / Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Powertrain:

Engine (EJ257), turbocharged system, intercooler, exhaust, fuel system, ignition system, cooling system, lubrication system.

Drivetrain:

Manual Transmission (TY757/TY856 variants), Center Differential (DCCD), Front Differential, Rear Differential, Axles, Driveshafts.

Chassis:

Suspension (Front MacPherson Strut, Rear Double Wishbone), Steering System (Hydraulic Power Steering), Brakes (ABS, EBD, High-Performance Calipers), Wheels and Tires.

Electrical:

Battery, charging system, starter, lighting, ignition, engine control (ECU/ECM), transmission control, Body Control Module (BCM), HVAC controls, audio system, power accessories, driver information system, diagnostic connectors (OBD-II).

Body And Interior:

Body panels, doors, windows, seats, trim, airbags, seatbelts, HVAC system, interior lighting.

Maintenance:

Routine maintenance, fluid changes (oil, coolant, brake fluid, transmission fluid, differential fluid), filter replacements, spark plug replacement, belt inspection/replacement.

Diagnostics:

Troubleshooting guides, diagnostic trouble codes (DTCs), electrical testing, component testing, system diagnostics.

Repair:

Engine overhaul, transmission repair, suspension component replacement, brake system repair, electrical component repair/replacement, body panel repair.

Special Procedures:

Turbocharger diagnosis and repair, DCCD system calibration and troubleshooting, AWD system service, alignment procedures, specific torque specifications for critical components.

Depth:

Comprehensive. Covers basic maintenance, detailed component disassembly/reassembly, advanced diagnostics, wiring diagrams, component specifications, and troubleshooting procedures suitable for professional technicians and experienced DIYers.

📊 Manual Specifications

File Type:

PDF (Portable Document Format)

Searchability:

Likely text-searchable for quick information retrieval, depending on the original scan quality.

Print Readability:

Designed for clear printing with diagrams, schematics, and text.

Binding:

N/A (Digital Download)

Paper Quality:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

Horizontally-opposed (Boxer) 4-cylinder, turbocharged and intercooled.

Engine Code:

EJ257

Displacement:

2.5 Liters (2457 cc)

Bore X Stroke:

99.5 mm x 79.0 mm

Compression Ratio:

8.4:1

Valve Train:

DOHC, 16 valves (4 per cylinder)

Horsepower:

305 hp @ 6000 rpm (SAE Net)

Torque:

290 lb-ft @ 4000 rpm (SAE Net)

Fuel Delivery:

Sequential multi-port fuel injection (MFI)

Fuel Type:

Premium Unleaded Gasoline (91 octane or higher recommended)

Turbocharger Type:

Twin-scroll IHI VF52 (or similar based on market)

Intercooler:

Top-mounted air-to-air intercooler

🔧 Transmission

Transmission Type:

6-speed manual transmission

Transmission Codes:

TY757 (likely variant for GVB/GRB chassis)

Dccd:

Driver Controlled Center Differential with Auto mode.

AWD System:

Symmetrical All-Wheel Drive with front and rear limited-slip differentials (LSD).

Manual Transmission Fluid:

Subaru Extra-S Gear Oil (or equivalent API GL-5 75W-90 synthetic)

📐 Dimensions

Length:

Approx. 4,415 mm (173.8 in)

Width:

Approx. 1,800 mm (70.9 in)

Height:

Approx. 1,475 mm (58.1 in)

Wheelbase:

Approx. 2,650 mm (104.3 in)

Curb Weight:

Approx. 1,505 kg (3,318 lbs) for Hatchback

Wheel Size:

18 x 8.5 inch

Tire Size:

245/40R18

Bolt Pattern:

5 x 114.3 mm

🛡️ Safety Features

NHTSA Rating:

Not specifically tested as a distinct WRX STI model by NHTSA for 2012, but the base Impreza received 5-star ratings in many categories.

IIHS Rating:

Similar to NHTSA, specific STI ratings are less common; base Impreza performed well.

ABS:

Standard Anti-lock Braking System with Electronic Brake-force Distribution (EBD).

Traction Control:

Standard Traction Control System (TCS) and Vehicle Dynamics Control (VDC).

AWD:

Symmetrical All-Wheel Drive provides enhanced traction and stability.

Airbags:

Front airbags, front side-impact airbags, side curtain airbags.

Seatbelts:

Three-point height-adjustable front seatbelts with pretensioners and force limiters.

Chassis Structure:

Ring-shaped reinforcement frame.

💡 Technology Features

Head Unit:

Typically a 6-speaker audio system with CD player, MP3 compatibility, SiriusXM Satellite Radio, Bluetooth connectivity, and auxiliary input.

Display:

Multi-function display in the center console or instrument cluster showing vehicle status and settings.

Cruise Control:

Standard electronic cruise control.

Keyless Entry:

Standard keyless entry and push-button start (depending on trim).

Bluetooth:

Bluetooth hands-free calling and audio streaming.

Usb Aux Ports:

Auxiliary audio input jack, potential USB port for device charging/audio (depending on market/trim).

🔧 Maintenance

Oil Change:

Every 3,000-5,000 miles or 3-6 months (severe driving conditions may require more frequent changes).

Air Filter Replacement:

Every 15,000-30,000 miles or as needed, check visually.

Cabin Air Filter Replacement:

Every 15,000-30,000 miles or annually.

Spark Plug Replacement:

Every 30,000-60,000 miles (depending on plug type, iridium recommended).

Coolant Flush:

Every 30,000-60,000 miles or 2-4 years.

Transmission Fluid Change:

Every 30,000-60,000 miles (especially under spirited driving).

Differential Fluid Change:

Every 30,000-60,000 miles.

Engine Oil:

SAE 5W-30 Synthetic (API SN or higher, ILSAC GF-5 or higher recommended). Refer to manual for specific viscosity charts.

Engine Oil Capacity:

Approx. 4.8 US quarts (4.5 liters) with filter change.

Coolant:

Subaru Super Coolant (Blue) or equivalent P-HOAT type antifreeze/coolant.

Brake Fluid:

DOT 3 or DOT 4 compatible fluid.

Piston Ring Land Cracks:

A concern in EJ257 engines, especially if subjected to excessive abuse or improper tuning. Requires careful inspection and potential replacement of pistons.

Oil Consumption:

Some EJ series engines can consume oil. Regular checks are vital.

Clutch Wear:

Performance-oriented clutch can wear faster with aggressive driving or repeated launches.

Sus Component Wear:

As with any performance car, bushings and suspension components can wear faster under demanding use.

📚 Vehicle History

Motorsport Legacy:

Subaru's extensive WRC (World Rally Championship) heritage, where the Impreza WRX STI achieved numerous victories and championships.

Previous Generations:

The 2012 model is part of the third generation (GR/GH) Impreza, with the WRX STI receiving specific performance upgrades. It followed the iconic GC8 and GD chassis generations.

Distinguishing Features Of This Generation:

Shift from sedan-only to a hatchback body style as the primary WRX STI offering in many markets, updated styling, and chassis refinements.

Production Years For Gv/Gr:

2008-2014 (with variations of WRX and STI within this period).

Manufacturing Location:

Mainly Japan (Gunma Plant).

🏆 Awards & Recognition

Car And Driver:

Often featured on Car and Driver's 10Best lists for its class and performance value in previous years.

Motortrend:

Frequently reviewed and praised by MotorTrend for its handling and rally-bred capabilities.

Enthusiast Following:

Strong enthusiast community and recognition for its performance tuning potential and rally heritage.