🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX STI

Generation:

G3

Model Code:

VAB (specific chassis codes may vary within G3 STI)

👋 Introduction

Vehicle Segment:

Compact Sports Sedan/Hatchback (Performance variant of Subaru Impreza)

Target Audience:

Enthusiasts, performance drivers, rally racing fans, DIY mechanics.

Key Competitors:

Mitsubishi Lancer Evolution, Volkswagen Golf GTI/R, Ford Focus RS, Honda Civic Type R.

Performance Heritage:

Iconic turbocharged boxer engine, Symmetrical All-Wheel Drive, rally-bred DNA, strong aftermarket support.

Manual Value Proposition:

Enables owners to perform complex maintenance, diagnostics, and repairs, saving on dealership labor costs and empowering customization.

📋 Manual Details

Geographical Coverage:

Global (primarily North America and Europe, but applicable to worldwide models with minor regional variations)

Estimated Page Count:

1500-2000+ pages (typical for a complete workshop manual of this scope)

Manual Type:

Complete Workshop Service and Repair Manual

Language:

English

Format:

Downloadable (typically PDF)

📖 Manual Coverage

Engine System:

EJ257 2.5L Turbocharged Boxer Engine: Mechanical, lubrication, cooling, fuel injection, ignition, emissions control, turbocharger, ECU diagnostics.

Transmission System:

6-Speed Manual Transmission (TY856WB1CA): Removal, installation, disassembly, assembly, internal components, lubrication, clutch system.

Drivetrain System:

All-Wheel Drive (AWD) System: DCCD (Driver Controlled Center Differential), front/rear differentials, driveshafts, CV joints, hub bearings.

Brake System:

Performance Braking System (Brembo): Front/rear caliper servicing, rotor replacement, brake fluid bleeding, ABS integration, parking brake.

Suspension Steering System:

Performance Suspension: Front struts (inverted), rear shock absorbers, springs, control arms, sway bars, steering rack, power steering system, alignment specifications.

Electrical System:

Wiring diagrams, starter, alternator, battery, lighting (headlights, taillights, fog lights), fuses, relays, body control module (BCM), ECU pinouts, sensor identification.

Body And Interior:

Exterior body panels, doors, hood, trunk, bumpers, interior trim, seats, airbags, climate control system, sound insulation.

HVAC System:

Air conditioning (compressor, condenser, evaporator), heating system, blower motor, controls, refrigerant.

Fuel System:

Fuel tank, fuel pump, fuel injectors, fuel pressure regulator, fuel lines, EVAP system.

Maintenance Procedures:

Oil and filter changes, air filter replacement, spark plug replacement, coolant flush and fill, brake fluid flush, differential fluid changes, transmission fluid changes.

Repair Procedures:

Engine component replacement (pistons, rods, bearings, valves), turbocharger rebuild, clutch replacement, transmission overhaul, differential rebuild, suspension component replacement, brake caliper rebuild.

Diagnostic Procedures:

OBD-II diagnostics, trouble code interpretation, sensor testing, circuit testing, pressure testing (fuel, oil, compression), leak detection.

Troubleshooting Guides:

Step-by-step troubleshooting for common and uncommon vehicle problems, symptom-based diagnostics.

Technical Specifications:

Torque specifications for all fasteners, critical measurements, clearances, alignment settings, engine data, transmission gear ratios.

Diagnostic Capability:

Advanced diagnostics including ECU parameter monitoring, actuator testing, and detailed electrical system troubleshooting.

Rebuild Capability:

Comprehensive procedures for complete engine and transmission rebuilds, including detailed disassembly and reassembly instructions.

Bodywork Coverage:

Detailed information on body panel alignment, repair techniques, and paint code references.

📊 Manual Specifications

File Type:

PDF (Portable Document Format)

Searchability:

Searchable text for quick information retrieval

Image Resolution:

High-resolution images, diagrams, and schematics for clarity

Printable:

Printable pages for on-the-go reference

Binding Type:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Code:

EJ257

Engine Type:

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

Displacement:

2.5 Liters (2457 cc)

Bore X Stroke:

99.5 mm x 80.0 mm

Horsepower:

305 hp @ 6000 rpm (SAE Net)

Torque:

290 lb-ft @ 4000 rpm (SAE Net)

Fuel Induction:

Sequential multi-port fuel injection (S-MPFI) with Denso or Bosch injectors

Fuel Requirement:

Premium Unleaded Gasoline (91 octane or higher recommended)

ECU Type:

Denso or Hitachi ECU (specific model varies)

Ignition System:

Electronic ignition with coil-on-plug design

🔧 Transmission

Transmission Type:

6-Speed Manual

Transmission Model:

TY856WB1CA

Optional Transmission:

None for WRX STI trim in this generation

Dccd:

Driver Controlled Center Differential (Manual control of center differential locking)

Gear Ratios:

1st: 3.636, 2nd: 2.235, 3rd: 1.524, 4th: 1.120, 5th: 0.971, 6th: 0.775, Reverse: 3.545 (Typical, verify with specific model year)

Transmission Fluid Type:

Subaru Extra-S Gear Oil (or equivalent API GL-5, SAE 75W-90 synthetic) - front and rear differentials

📐 Dimensions

Length:

4,415 mm (Hatchback) / 4,580 mm (Sedan)

Width:

1,795 mm

Height:

1,475 mm (Hatchback) / 1,450 mm (Sedan)

Wheelbase:

2,650 mm

Curb Weight:

Approx. 1,505 kg (Hatchback) / 1,520 kg (Sedan)

Gross Vehicle Weight Rating Gvwr:

Approx. 1,950 kg

Wheel Size:

18-inch alloy wheels

Tire Size:

245/40R18

Bolt Pattern:

5 x 114.3 mm (5 x 4.5 inches)

🛡️ Safety Features

NHTSA Safety Rating:

Generally good ratings for its era, though specific results for the STI variant might differ slightly from standard Impreza models. Expect 4-5 star ratings in key categories.

Traction Control:

SI-DRIVE (Subaru Intelligent Drive) with Sport Sharp mode, Traction Control System (TCS), Vehicle Dynamics Control (VDC).

AWD System:

Symmetrical All-Wheel Drive with DCCD for enhanced traction and handling control.

Airbags:

Front dual-stage airbags, front side-impact airbags, front and rear side-curtain airbags.

Seatbelts:

Three-point seatbelts with pretensioners and force limiters.

Chassis Construction:

High-strength steel safety cage construction.

💡 Technology Features

Audio System:

Standard Subaru audio system with CD player, MP3 capability, auxiliary input, and available Bluetooth connectivity. Higher trims may feature enhanced audio systems (e.g., Harman Kardon).

Display:

Multi-function display in the center console for climate control, audio, and vehicle settings.

Si Drive:

Subaru Intelligent Drive system with three modes: Intelligent (I), Sport (S), and Sport Sharp (S#), affecting throttle response, engine mapping, and VDC settings.

Cruise Control:

Standard cruise control

Bluetooth:

Available Bluetooth hands-free phone and audio streaming

Usb Port:

Standard USB port for charging and audio playback

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles (6,000 km) or 6 months, whichever comes first (severe driving conditions; standard is often 7,500 miles/12 months).

Engine Air Filter:

Replace every 15,000 miles (24,000 km) or 12 months.

Spark Plugs:

Replace every 60,000 miles (96,000 km) (iridium type).

Coolant Flush:

First replacement at 60,000 miles (96,000 km) or 48 months, then every 30,000 miles (48,000 km) or 24 months.

Transmission Fluid:

Inspect every 15,000 miles (24,000 km), replace every 30,000 miles (48,000 km) (manual transmission and differentials).

Engine Oil Type:

SAE 5W-30 Synthetic (API SN or higher)

Engine Oil Capacity:

5.8 US quarts (5.5 Liters) with filter change

Coolant Type:

Subaru Super Coolant (Blue) or equivalent silicate-free, long-life coolant.

Brake Fluid Type:

DOT 3 or DOT 4

Head Gaskets:

While EJ257 engines are generally robust, earlier iterations of Subaru engines had head gasket issues. Though less common on later models, it's a potential concern. The manual will cover diagnosis and replacement.

Ringland Failure:

Can occur on heavily modified or poorly maintained EJ257 engines due to increased cylinder pressures. Proper tuning and maintenance are critical. Manual covers piston/ring replacement.

Turbocharger Wear:

Regular oil changes and allowing the turbo to cool down after spirited driving are crucial for longevity. Manual details turbo inspection and replacement.

Clutch Wear:

As with any performance manual transmission, the clutch can wear faster with aggressive driving. Manual provides clutch inspection and replacement procedures.

📚 Vehicle History

Subaru Rally Heritage:

Subaru's long and successful history in the World Rally Championship (WRC) directly influences the design and engineering of the Impreza WRX STI.

G3 Introduction:

The G3 Impreza (third generation) launched in 2007, with the STI variant following. It represented a significant styling departure from previous generations, featuring a hatchback option and a more aerodynamic, 'jet-fighter grille' front end.

2012-2014 Updates:

These model years represent the facelifted version of the G3 STI, featuring updated styling (front fascia, wheels), suspension tuning, and minor powertrain refinements. The sedan body style became the primary offering for the STI in many markets during this period.

Production Location:

Gunma Plant, Japan

Production Years For G3 Sti:

2008-2014

🏆 Awards & Recognition

Car And Driver 10Best:

The Subaru WRX STI (and its predecessors) has been a frequent recipient of Car and Driver's '10Best' list for its performance and handling capabilities.

Motor Trend Awards:

Often recognized by automotive publications for its performance, AWD system, and rally-inspired driving dynamics.

Performance Reviews:

Consistently praised for its sharp steering, strong acceleration, and exceptional all-weather grip.