🏷️ Basic Information Identification Make: Subaru Model: Impreza WRX STi Year: 2004 Codes Chassis Code: GDB 👋 Introduction Market Position Positioning: High-performance compact sedan and wagon, renowned for its rally heritage and all-wheel-drive system. Competitive Analysis Competitors: Mitsubishi Lancer Evolution, Ford Focus RS, Volkswagen Golf GTI/R32 Key Features Performance Focus: Emphasis on turbocharged engine performance, Symmetrical All-Wheel Drive, and track-ready handling. Target Audience Audience: Enthusiast owners, DIY mechanics, and performance tuning shops. 📋 Manual Details Coverage Areas Primary Coverage: Complete Service and Repair for 2004 Subaru Impreza WRX STi Secondary Coverage: Routine Maintenance, Tune-up Procedures, Specifications Page Count Estimated Page Count: Detailed page count not provided, but described as 'most complete ever compiled'. Manual Type Type: Service Repair Manual Language Language: English Format File Format: PDF Delivery Method: INSTANT DOWNLOAD 📖 Manual Coverage Systems Covered Engine: Engine Removal/Installation, Cylinder Head/Valve Train, Engine Block, Engine Lubrication, Engine Repair, Valve Timing Procedures, Chain & Gear Replacement, Tensioner Adjustments, Tightening Torques, Timing Marks, Valve Timing Instructions, Tensioner Release & Reset Methods, Chain Routing & Sprocket/Gear Valve Timing Marks Drivetrain: Transaxle, Clutch, Manual Transmission, Automatic Transmission (if applicable to WRX STi model), Differential, Driveshaft Chassis: Steering, Suspension, Brakes (including ABS), Body Electrical: Electrical System, Wiring Diagrams, SRS (Supplemental Restraint System) HVAC: Cooling and Heating, Heater and Air Conditioning, Automatic Climate Control Fuel Emissions: Intake Manifold/Exhaust System, Fuel and Emissions, Exhaust, Emissions Control, Ignition Engine Management System: Fuel injection, ignition timing, sensor operations, and ECU logic. Procedures Included Maintenance: Routine Maintenance, Tune-up Procedures Repair: Engine Repair, Transmission Repair, Brake Repair, Suspension Repair, Electrical Diagnosis and Repair, Body Panel Repair Diagnostics: Troubleshooting guides are implied for all covered systems. Installation: General Removal & Installation Instructions Special Procedures: Valve Timing Procedures, Chain & Gear Replacement, Tensioner Adjustments, Tightening Torques, Valve Timing Instructions, Tensioner Release & Reset Methods, Chain Routing & Sprocket/Gear Valve Timing Marks Troubleshooting: Systematic troubleshooting guides for common and uncommon faults across all major vehicle systems. Technical Depth Depth: Comprehensive from basic maintenance to advanced engine and drivetrain overhaul, including detailed diagnostics and electrical schematics. Diagnostic Tools: Covers procedures for using OBD-II scanners and specific Subaru diagnostic tools for fault code retrieval and live data analysis. Rebuild Procedures: Detailed steps for engine and transmission disassembly, inspection, repair, and reassembly. 📊 Manual Specifications File Format Compatibility: All Versions of Windows & Mac Requirements: Adobe PDF Reader & WinZip File Type: PDF (Portable Document Format) Print Quality Printability: All pages are printable Binding Type Binding: Digital Download (No physical binding) Paper Type Paper Quality: N/A (Digital format) ⚙️ Engine Specifications Primary Engine Engine Code: EJ257 Engine Type: 2.5L Turbocharged Horizontally Opposed (Boxer) 4-Cylinder Performance Horsepower: 265 HP @ 6000 RPM (approx.) Torque: 247 lb-ft @ 4000 RPM (approx.) Fuel System Fuel Delivery: Sequential multi-port fuel injection, Turbocharged with intercooler Engine Management ECU Type: Specific ECU details covered in manual for diagnosis and tuning. 🔧 Transmission Standard Transmission Type: 6-Speed Manual Transmission Optional Optional Transmission: Not typically offered on WRX STi models; focus is on the performance manual. Features AWD System: Subaru Symmetrical All-Wheel Drive with Driver Controlled Center Differential (DCCD) 📐 Dimensions Exterior Body Styles: Sedan, Wagon Weights Curb Weight Sedan: Approx. 3280 lbs (1488 kg) Curb Weight Wagon: Approx. 3350 lbs (1519 kg) 🛡️ Safety Features Ratings NHTSA Front Driver: 5-Star (for 2004 model year sedan) NHTSA Front Passenger: 5-Star (for 2004 model year sedan) Active Features Active Safety: ABS (Anti-lock Braking System), AWD (All-Wheel Drive) Passive Features Passive Safety: Front airbags, Side airbags (optional/standard depending on trim), 3-point seatbelts 💡 Technology Features Infotainment Infotainment System: Basic AM/FM/CD audio system with optional premium sound. No integrated navigation or advanced connectivity typically found in modern vehicles. Driver Assistance Driver Assistance: Primarily focused on mechanical systems like AWD and ABS, not electronic driver aids. Connectivity Connectivity Features: Limited to standard audio inputs (e.g., AUX jack on some models/aftermarket units). 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 3,750 miles or 6 months (severe duty) / 7,500 miles or 12 months (normal duty), refer to manual for specifics. Timing Belt Interval: 105,000 miles or 105 months (for EJ257 engines, verify with manual for exact interval). Fluid Specifications Engine Oil: SAE 5W-30 (check manual for specific Subaru or API/ILSAC ratings) Transmission Fluid: GL-5 75W-90 Synthetic (for manual transmission, check manual for specific Subaru fluid or equivalency) Differential Fluid: GL-5 75W-90 Synthetic (front and rear, check manual) Coolant: Subaru Genuine Coolant (Blue) or equivalent P-HOAT coolant Known Issues Engine Wear: Piston ring land failures, ring land cracking (especially with aggressive tuning), head gasket leaks (though less common on EJ257 than earlier EJ25 variants). Turbocharger: Potential for turbo seal failure or bearing wear leading to oil consumption and smoke. Clutch: Wear and tear is common given the performance-oriented nature of the vehicle. 📚 Vehicle History Brand Heritage Heritage: Subaru's long-standing success...