🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX STI

Year:

2015

Chassis Code:

GV/GRB (for hatchback, though 2015 is primarily VA generation sedan)

Engine Code:

EJ257

👋 Introduction

Segment:

Performance Compact Sedan / Rally-Bred Sport Compact

Reputation:

Iconic performance model known for its rally heritage, all-wheel-drive system, and powerful turbocharged engine.

Competitors:

Mitsubishi Lancer Evolution (prior to discontinuation), Ford Focus RS, Volkswagen Golf R, Honda Civic Type R

Drivetrain:

Symmetrical All-Wheel Drive (AWD) with Driver Controlled Center Differential (DCCD)

Engine Type:

Turbocharged Boxer Engine

Performance Focus:

Designed for high-performance driving, handling, and track capability.

Purpose:

Essential resource for owners and technicians performing maintenance, diagnostics, and repairs on the 2015 Subaru Impreza WRX STI.

📋 Manual Details

Systems:

Engine, Transmission (Manual & Automatic - though STI is primarily manual), Drivetrain (AWD System, Differentials), Suspension, Steering, Brakes, Electrical System, HVAC, Body & Chassis, Emissions, Diagnostics, Troubleshooting, Specifications

Estimated Pages:

~2000-3000 (typical for comprehensive factory service manuals)

Type:

Factory Service Repair Workshop Manual

Language:

English

Format:

Downloadable PDF

📖 Manual Coverage

Engine Mechanical:

Engine assembly, disassembly, cylinder head, block, crankshaft, pistons, connecting rods, lubrication system, cooling system, intake system, exhaust system, turbocharger system

Fuel System:

Fuel injectors, fuel pump, fuel lines, fuel pressure regulator, evaporative emission control (EVAP)

Ignition System:

Ignition coils, spark plugs, ignition timing

Transmission Drivetrain:

Manual transmission (6-speed TY85), clutch system, all-wheel-drive (AWD) system, center differential, front and rear differentials, driveshafts, wheel hubs

Suspension Steering:

Front and rear suspension components (struts, springs, control arms, sway bars), steering rack, power steering system

Brake System:

Front and rear brake calipers (Brembo), rotors, brake pads, master cylinder, brake lines, ABS system, electronic brake-force distribution (EBD), brake fluid specifications

Electrical System:

Battery, alternator, starter, lighting system, power windows, power locks, infotainment system, instrument cluster, wiring diagrams, fuses, relays, ECU/ECM diagnostics

HVAC System:

Air conditioning, heater core, blower motor, climate control unit

Body Chassis:

Body panels, doors, hood, trunk, interior trim, chassis components, corrosion protection

Emissions Control:

Catalytic converter, oxygen sensors, secondary air injection system

Maintenance:

Oil changes, filter replacements, spark plug replacement, coolant flushes, brake fluid service, transmission fluid service, differential fluid service, air filter replacement

Diagnostics Troubleshooting:

OBD-II diagnostic codes, symptom-based troubleshooting, component testing procedures, wiring diagram interpretation

Repair Rebuild:

Engine overhaul, transmission rebuild, suspension component replacement, brake caliper rebuild, steering rack replacement, clutch replacement, turbocharger replacement, ECU/ECM replacement

Installation Adjustment:

Timing belt/chain replacement, turbocharger installation, suspension alignment specifications, brake bleeding procedures, clutch pedal adjustment

Depth:

Comprehensive factory-level detail, including torque specifications, component tolerances, diagnostic trouble codes (DTCs), wiring schematics, and step-by-step repair instructions for all major systems.

📊 Manual Specifications

File Type:

PDF (Portable Document Format)

Searchability:

Searchable text for quick information retrieval

Quality:

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

Binding:

N/A (Digital Download)

Paper:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Code:

EJ257

Engine Type:

2.5L DOHC 16-Valve Turbocharged Subaru BOXER Engine

Displacement:

2457 cc (2.5 Liters)

Horsepower:

305 hp @ 6000 rpm

Torque:

290 lb-ft @ 4000 rpm

Fuel Delivery:

Sequential Multi-Port Fuel Injection (SMPI) with Side Feed Injectors

Fuel Type:

Premium Unleaded Gasoline (91 Octane or Higher Recommended)

Ratio:

8.2:1

Type:

Twin-Scroll Turbocharger with Intercooler

🔧 Transmission

Type:

6-Speed Manual Transmission (TY85)

Type:

N/A for WRX STI model (Manual transmission only)

Drivetrain Coupling:

Symmetrical All-Wheel Drive (AWD) with Driver Controlled Center Differential (DCCD)

Manual Transmission Fluid:

Subaru ExtraS synthetic gear oil (75W-90 GL-5) or equivalent

Front Differential Fluid:

Subaru ExtraS synthetic gear oil (75W-90 GL-5) or equivalent

Rear Differential Fluid:

Subaru ExtraS synthetic gear oil (75W-90 GL-5) or equivalent

📐 Dimensions

Length:

180.0 inches (4572 mm)

Width:

70.7 inches (1796 mm)

Height:

58.1 inches (1476 mm)

Wheelbase:

104.0 inches (2641 mm)

Curb Weight:

Approximately 3,400 - 3,500 lbs (1542 - 1588 kg)

Gross Vehicle Weight Rating:

Not explicitly stated but typically around 4,500 lbs.

🛡️ Safety Features

NHTSA Overall Rating:

5-Star Overall (NHTSA ratings vary by specific configuration and testing)

Traction Control:

Vehicle Dynamics Control (VDC) with SI-Drive

Braking System:

Four-wheel Anti-lock Braking System (ABS), Electronic Brake-force Distribution (EBD), Brake Assist

Airbags:

Frontal, side-curtain, front seat-mounted side airbags, driver's knee airbag

Body Structure:

Advanced Ring-Shaped Reinforcement Frame

💡 Technology Features

Head Unit:

Subaru Starlink infotainment system with 6.2-inch touchscreen, AM/FM/CD/MP3, SiriusXM Satellite Radio, USB port, auxiliary input, Bluetooth connectivity.

Audio System:

6-speaker audio system (optional upgraded system available).

Performance Features:

SI-Drive (Subaru Intelligent Drive) with Intelligent, Sport, and Sport Sharp modes; Multi-Mode Driver Controlled Center Differential (DCCD).

Bluetooth:

Bluetooth hands-free phone connectivity and audio streaming.

Gauges:

Multi-information display in instrument cluster, including boost gauge, G-force meter, and performance timers.

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles (6,000 km) or 6 months, whichever comes first, with severe driving conditions (performance driving, track use) recommending more frequent changes.

Engine Air Filter:

Inspect every 15,000 miles (24,000 km), replace as needed or every 30,000 miles (48,000 km).

Spark Plugs:

Replace every 60,000 miles (96,000 km) or as per manual specification for iridium plugs.

Transmission Fluid:

Replace every 30,000 miles (48,000 km) or 24 months for manual transmission and differentials, with severe driving conditions recommending more frequent service.

Engine Oil:

SAE 0W-20, API SN or ILSAC GF-5 certified (use high-quality synthetic oil)

Coolant:

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

Brake Fluid:

DOT 3 or DOT 4

Engine Wear:

Piston ring land failures and head gasket issues can occur in high-mileage or poorly maintained examples, particularly if pushed hard without proper servicing.

Clutch Wear:

Can be susceptible to premature wear if subjected to aggressive driving, frequent launches, or improper clutch operation.

Differential Noise:

Rear differential whine or noise can sometimes develop, often related to fluid breakdown or internal wear.

📚 Vehicle History

Motorsport Connection:

Direct lineage from Subaru's World Rally Championship (WRC) success, with the WRX STI being the road-going homologation model.

Generations:

The 2015 model marks the introduction of the VA generation Impreza WRX STI, moving to a sedan-only platform for the US market, and featuring significant updates to the chassis and drivetrain.

Manufacturing Location:

Ota City, Gunma Prefecture, Japan

🏆 Awards & Recognition

Performance Awards:

Consistently praised by automotive journalists for its handling, AWD capabilities, and raw performance. Often appears on 'best of' lists for performance cars in its class.

Car And Driver Editors Choice:

Frequently recognized by publications like Car and Driver for its driving dynamics and rally-bred performance.

Emission Standards:

Meets EPA and CARB emission standards for the model year.