🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX STI

Year:

2015

Chassis Code:

GVB/GRB (Wagon/Hatchback based)

Engine Code:

EJ257

👋 Introduction

Segment:

Performance Compact Sedan/Hatchback

Target Audience:

Enthusiasts, Performance Drivers, DIY Mechanics, Professional Technicians

Key Competitors:

Mitsubishi Lancer Evolution, Volkswagen Golf R, Ford Focus RS (though often categorized slightly differently due to AWD focus)

Drivetrain:

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

Engine:

High-performance turbocharged boxer engine

Suspension:

STI-tuned performance suspension for superior handling

Brakes:

Performance Brembo braking system

Rally Heritage:

Direct lineage from Subaru's successful World Rally Championship (WRC) program

📋 Manual Details

Primary Coverage:

Full Workshop Service and Repair

Secondary Coverage:

Diagnostics, Troubleshooting, Maintenance, Reassembly

Estimated Pages:

2000+

Type:

Workshop Service Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Powertrain:

Engine (EJ257), Turbocharger System, Exhaust System, Fuel System, Cooling System

Drivetrain:

All-Wheel Drive System (Symmetrical AWD), Differential Units (Front, Center DCCD, Rear), Driveshafts, Axles

Transmission:

6-Speed Manual Transmission (TY856)

Suspension:

Front MacPherson Struts, Rear Double Wishbone, STI-specific Tuning, Springs, Dampers, Bushings

Brakes:

Front 6-Piston Brembo Calipers, Rear 2-Piston Brembo Calipers, ABS, EBD, Brake Fluid Specifications

Steering:

Power Assisted Rack and Pinion, Steering Column Components

Electrical:

Battery, Charging System, Ignition System, Lighting, Fuses, Relays, ECUs, Wiring Diagrams, CAN Bus System

Body And Chassis:

Body Panels, Doors, Hood, Trunk, Bumpers, Chassis Structure, Sound Deadening

Interior:

Seating, Dashboard, Trim Panels, Airbags, Seatbelts, HVAC System

Diagnostics:

OBD-II Procedures, DTC Codes, Scan Tool Usage, Sensor Testing

Engine Repair:

Engine Overhaul, Piston Ring Replacement, Valve Adjustment, Timing Belt/Chain Service, Turbocharger Rebuild/Replacement

Transmission Repair:

Clutch Replacement, Gearbox Rebuild, Differential Service, DCCD System Adjustment

Brake Service:

Brake Pad/Rotor Replacement, Caliper Overhaul, Bleeding Procedures, ABS Component Testing

Suspension And Steering Repair:

Strut Replacement, Bushing Replacement, Wheel Alignment Specifications, Power Steering System Service

Electrical Diagnostics:

Wiring Harness Repair, Sensor Troubleshooting, ECU Diagnosis, Component Testing

Body And Interior Repair:

Panel Replacement, Dent Repair, Trim Installation, Airbag System Diagnosis

Routine Maintenance:

Oil Changes, Filter Replacements, Spark Plug Service, Fluid Checks and Replenishment

Troubleshooting:

System-specific diagnostic flowcharts and fault isolation procedures

Depth:

Comprehensive: From basic maintenance to complete engine and transmission rebuilds, including detailed diagnostic procedures and specifications.

Diagnostic Capabilities:

Advanced, including ECU learning/reset procedures, sensor data interpretation, and detailed electrical system troubleshooting.

Rebuild Procedures:

Detailed steps for major component overhauls, including torque specifications, clearances, and assembly sequences.

📊 Manual Specifications

Type:

PDF

Searchability:

Searchable text content for quick information retrieval.

Digital Rights:

Instant Download, Accessible on Multiple Devices

Resolution:

High resolution, suitable for printing individual pages or sections.

Type:

N/A (Digital Download)

Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

Horizontally Opposed (Boxer) 4-Cylinder, Turbocharged, Intercooled

Displacement:

2.5 Liters (2457 cc)

Bore X Stroke:

99.5 mm x 79.0 mm

Compression Ratio:

8.4:1

Valve Train:

DOHC, 4 Valves per Cylinder, Variable Valve Lift and Timing (AVCS)

Horsepower:

305 hp @ 6000 rpm

Torque:

290 lb-ft (393 Nm) @ 4000 rpm

Induction:

Multi-Point Fuel Injection (MPI) with Turbocharging

Fuel Type:

Premium Unleaded Gasoline (91 Octane or higher recommended)

Fuel Pump:

High-flow, in-tank electric fuel pump

Engine Oil Capacity:

5.0 US quarts (4.7 Liters) with filter change

Engine Oil Type:

SAE 5W-30 Synthetic (per Subaru specification)

Coolant Type:

Subaru Super Coolant (Blue) or equivalent HOAT coolant

🔧 Transmission

Type:

6-Speed Manual Transmission

Model Code:

TY856 (specific variant)

Dccd:

Driver Controlled Center Differential (manual operation with auto modes)

Differentials:

Front Helical Limited-Slip Differential (LSD), Rear Torsen Limited-Slip Differential (LSD)

Transmission Fluid Type:

API GL-5, SAE 75W-90 Synthetic Gear Oil (check specific service bulletin for exact specs)

Transmission Oil Capacity:

Approx. 3.3 US quarts (3.1 Liters)

📐 Dimensions

Wheelbase:

104.1 inches (2645 mm)

Length:

173.4 inches (4405 mm)

Width:

70.1 inches (1780 mm)

Height:

58.1 inches (1475 mm)

Ground Clearance:

5.0 inches (127 mm)

Curb Weight:

Approx. 3417 lbs (1550 kg)

Gross Vehicle Weight Rating:

Approx. 4542 lbs (2060 kg)

Wheel Size:

18 x 8.5 inches (standard)

Bolt Pattern:

5 x 114.3 mm (5x4.5 inches)

Tire Size:

245/40R18 (standard)

🛡️ Safety Features

IIHS Rating:

Good (various categories, check specific model year reports)

NHTSA Rating:

4-Star Overall (check specific model year reports)

ABS:

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

Traction Control:

Multi-mode Traction Control System (TCS)

Stability Control:

Vehicle Dynamics Control (VDC) with STI tuning

AWD System:

Symmetrical All-Wheel Drive with DCCD for enhanced traction and stability

Airbags:

Front, Side, Curtain Airbags; Driver's Knee Airbag

Seatbelts:

Pretensioners and Load Limiters

Body Structure:

High-strength steel body structure

💡 Technology Features

Head Unit:

Subaru's infotainment system with 6.1-inch touchscreen (standard on STI), Bluetooth connectivity, USB port.

Audio System:

Available 9-speaker Harman Kardon audio system.

Eyesight System:

Not typically available on the performance-focused WRX STI for this model year. Focus is on driver engagement.

Rearview Camera:

Standard on most trims for 2015.

Bluetooth:

Standard for hands-free calling and audio streaming.

Usb Ports:

Standard for device charging and media playback.

Si Drive:

Subaru Intelligent Drive system allowing driver selection of Intelligent, Sport, and Sport Sharp modes, affecting throttle response, VDC, and DCCD behavior.

Dccd Control:

Manual control of the center differential's locking force for various driving conditions.

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles or 6 months (severe driving) or 7,500 miles or 12 months (normal driving), though performance driving may warrant more frequent changes. Consult manual.

Air Filter Replacement:

Every 15,000 miles or 12 months, or as needed based on driving conditions.

Spark Plug Replacement:

Every 60,000 miles (iridium type recommended).

Transmission Fluid Change:

Every 30,000 miles (manual transmission), check AWD fluid and differential fluid intervals in manual.

Brake Fluid Type:

DOT 3 or DOT 4 Synthetic Brake Fluid

Power Steering Fluid:

Subaru Genuine ATF or equivalent DEXRON III/MERCON compatible fluid

Piston Ring Land Cracks:

A known concern in some EJ25 engines, particularly when subjected to aggressive tuning or abuse. Proper maintenance and avoiding detonation are crucial.

Clutch Wear:

Can be accelerated with aggressive driving. The manual covers inspection and replacement procedures.

Dccd Actuator Issues:

Less common, but electronic issues can arise with the DCCD system. The manual details diagnostic steps.

Suspension Bushings:

Like many performance cars, bushings can wear over time, affecting handling. Manual covers replacement.

📚 Vehicle History

Rally Success:

Subaru's long and successful history in the World Rally Championship (WRC), contributing to the WRX STI's performance DNA.

Wrx Lineage:

The WRX STI is the pinnacle of the Impreza line, evolving from rally homologation specials to highly capable performance street cars.

Third Generation Gv Gr:

The 2015 model is part of the 'GV'/'GR' generation (third generation) which saw the adoption of the hatchback body style as standard for the WRX and WRX STI globally, though sedan variants were produced in some markets.

Manufacturing Plant:

Ota City, Gunma, Japan

🏆 Awards & Recognition

Performance Accolades:

Consistently praised by automotive journalists for its sharp handling, powerful engine, and rally-bred character. Often appears on 'best performance car' lists.

Consumer Ratings:

Highly rated by owners for its driving dynamics and performance capabilities.

Emissions Standards:

Meets relevant emissions standards for its model year (e.g., EPA, CARB depending on market).