🏷️ Basic Information Identification Make: Subaru Model: Impreza WRX STI Year: 2004 Generation Generation Code: GDB (GD) Codes Chassis Code: GDB 👋 Introduction Market Position Positioning: High-performance compact sedan/hatchback, rally-bred heritage Competitive Analysis Competitors: Mitsubishi Lancer Evolution, Subaru WRX (non-STI), Honda Civic Si, Volkswagen GTI, MazdaSpeed3 Key Features Performance Orientation: Emphasis on turbocharged engine, all-wheel drive (AWD), and agile handling Rally Heritage: Direct lineage from Subaru's World Rally Championship (WRC) success 📋 Manual Details Coverage Areas Primary Coverage: All models and all repairs A-Z Specific Systems Covered: Engine, Transmission, Chassis, Body, Electrical System Page Count Estimated Page Count: High (typical FSMs are 1000+ pages) Manual Type Type: Official Factory Service Manual (FSM) / Repair Manual / Workshop Manual Language Language: English Format Digital Format: PDF Compatibility Operating Systems: Windows & Mac 📖 Manual Coverage Systems Covered Engine Mechanical: Mechanical parts, diagnostics, cooling, lubrication, ignition, starting Engine Fuel Air Exhaust: Fuel injection, air intake, exhaust systems Transmission Manual: 5-speed manual (5MT) and 6-speed manual (6MT) transmissions Transmission Automatic: 4-speed automatic transmission (4AT) (less common for STI, but often included in comprehensive FSMs for model range) Drivetrain: Transfer case, driveshaft, differentials, clutch Suspension: Front and rear suspension systems Brakes: Antilock Braking System (ABS), brake system components, parking brake Steering: Steering system components Body Exterior: Body panels, glass, windows, mirrors, lighting, wipers/washers Body Interior: Instrument panel, seats, locks, security, sunroof, interior finishing Climate Control: HVAC system, climate system components Safety Restraints: Airbags, seatbelts Electrical General: General diagnosis, component locations Electrical Wiring: Comprehensive wiring diagrams, signals Procedures Included Maintenance: Scheduled maintenance, fluid checks and changes, filter replacements Diagnostics: Dedicated troubleshooting guides, diagnostic procedures for various systems Repair: Step-by-step repair instructions for all major components Disassembly Assembly: Exploded diagrams for component disassembly and reassembly Wiring Diagrams Detail: High level of detail in wiring schematics, showing component connections and routing. Technical Depth Depth: Comprehensive (covers maintenance to major overhauls and diagnostics) 📊 Manual Specifications File Format Format: ZIP archive containing PDF files Print Quality Printability: Printable pages (user can print selectively) Binding Type Binding Type: N/A (Digital format) Paper Type Paper Type: N/A (Digital format) File Size Size Mb: 317 MB ⚙️ Engine Specifications Primary Engine Engine Code: EJ257 Engine Type: 2.5L Boxer-4 Turbocharged (EJ257) Performance Horsepower Hp: 300 hp @ 6000 RPM (approximate, US spec) Torque Lb Ft: 300 lb-ft @ 4000 RPM (approximate, US spec) Fuel System Fuel Delivery: Multi-point Fuel Injection (MPI) Recommended Fuel: Premium Unleaded (91+ Octane) Engine Management ECU Type: Subaru Select Monitor (SSM) 🔧 Transmission Standard Type: 6-speed Manual Transmission (6MT) Optional Type: 4-speed Automatic Transmission (4AT) (less common for STI, often not specified for STI models) Features All Wheel Drive: Symmetrical All-Wheel Drive (AWD) with Driver Controlled Center Differential (DCCD) on 6MT models 📐 Dimensions Exterior Length In: 173.8 in Width In: 69.7 in Height In: 56.1 in Weights Curb Weight Lbs: 3263 lbs (approximate for 6MT sedan) 🛡️ Safety Features Ratings NHTSA Front Impact: 5-Star (for driver and passenger, typical for this era) NHTSA Side Impact: 5-Star (typical for this era) Active Features Traction Control: Yes (often linked to AWD system) Electronic Stability Control: Subaru Vehicle Dynamics Control (VDC) system Passive Features Airbags: Front airbags, side-impact airbags Seatbelts: Front pre-tensioners and load limiters 💡 Technology Features Infotainment Audio System: Factory AM/FM/CD player, premium sound system (optional) Driver Assistance ABS: Standard Antilock Braking System (ABS) AWD Control: Driver Controlled Center Differential (DCCD) for manual transmission models, allowing variable front/rear torque split adjustment. 🔧 Maintenance Service Intervals Oil Change Interval: Every 3,750 miles or 3.75 months, or 7,500 miles/7.5 months with synthetic oil (check specific recommendations) Timing Belt Replacement: 105,000 miles (for EJ257 engine) Fluid Specifications Engine Oil Type: SAE 0W-30 or 5W-30 Synthetic (refer to manual for specific viscosity based on temperature) Coolant Type: Subaru Super Coolant (Blue) or equivalent Transmission Fluid Type 6Mt: Subaru Extra-S Gear Oil or equivalent SAE 75W-90 GL-5 Known Issues Head Gaskets: Less prone to blown head gaskets than earlier EJ20/EJ25 engines due to improved design, but still a potential failure point under high stress. Ring Lands: Susceptible to ring land failure on pistons, especially with aggressive tuning or detonation, common in high-mileage or abused EJ257 engines. Clutch Wear: Clutch wear can be accelerated with aggressive driving and frequent launches. 📚 Vehicle History Brand Heritage Brand Focus: AWD technology, horizontally-opposed engines, rally racing Model Evolution Generation 2004: Part of the second generation (GDB) Impreza, representing a significant performance uplift and distinct STI styling Production Manufacturing Location: Japan 🏆 Awards & Recognition Recognitions Performance Awards: Consistently praised by automotive journalists for its performance, handling, and AWD system, often featured in 'best performance car' lists.