🏷️ Basic Information Identification Make: Subaru Model: Impreza WRX STI Model Variant: WRX STI Years Covered: 2004-2005 Codes Chassis Codes: GDB (Specific variants for STI) 👋 Introduction Market Position Vehicle Segment: Performance Compact Sedan/Wagon, Rally-bred Sports Car. Competitive Analysis Key Competitors: Mitsubishi Lancer Evolution, Ford Focus RS, Honda Civic Type R (in broader performance segments). Key Features Vehicle Highlights: Iconic turbocharged boxer engine, advanced Symmetrical All-Wheel Drive, performance-tuned suspension, DCCD, potent braking system, rally heritage. Manual Value Proposition Diy Enablement: Empowers owners to perform a wide range of repairs and maintenance, saving on labor costs and fostering a deeper understanding of their vehicle. 📋 Manual Details Coverage Areas General Coverage: Comprehensive repair and maintenance for the Subaru Impreza WRX STI. Specific Systems: Engine, Drivetrain, Suspension, Steering, Brakes, Electrical System, HVAC, Bodywork, Emissions. Page Count Estimated Page Count: Approximately 2000+ pages (typical for comprehensive factory service manuals of this era). Manual Type Manual Type: Factory Service Manual (FSM) / Repair Manual Language Language: English Format Digital Format: PDF 📖 Manual Coverage Systems Covered Engine Management: Detailed diagnostics and repair procedures for the EJ257 engine, including ECU functions, sensors, actuators, and fuel injection systems. Drivetrain And AWD: In-depth coverage of the symmetrical All-Wheel Drive system, including DCCD (Driver Controlled Center Differential), viscous coupling unit, front/rear differentials, and gearbox maintenance/overhaul. Suspension And Steering: Complete information on the performance-tuned suspension, including strut assembly removal/installation, alignment procedures, power steering system diagnostics, and steering rack overhaul. Braking System: Detailed procedures for the performance Brembo braking system, including rotor and pad replacement, caliper servicing, brake fluid bleeding, and ABS system diagnostics. Electrical System: Comprehensive wiring diagrams, troubleshooting guides for lighting, starting/charging systems, infotainment, and various control modules. Procedures Included Routine Maintenance: Oil changes, filter replacements (oil, air, fuel), coolant flush, spark plug replacement, belt inspection and replacement. Engine Repair: Top-end rebuilds (cylinder heads), bottom-end overhauls, turbocharger diagnostics and replacement, intercooler system servicing. Transmission Overhaul: Detailed steps for clutch replacement, gearbox disassembly and reassembly, transfer case servicing, and differential rebuilds. Troubleshooting Diagnostics: Systematic diagnostic trees and fault code interpretation for common and complex issues. Technical Depth Depth Of Coverage: Covers everything from basic fluid checks and filter changes to complete engine and transmission rebuilds, including component-level diagnostics and specifications. 📊 Manual Specifications File Format File Type: PDF Searchability: Searchable text for quick information retrieval. Print Quality Printability: High-resolution, optimized for clear printing of text and diagrams. Zoom Capability: Excellent zoom capability for detailed inspection of diagrams and text. Binding Type Binding Description: N/A (Digital PDF format) Paper Type Paper Description: N/A (Digital PDF format) Compatibility Operating Systems: Compatible with all Windows and macOS operating systems. ⚙️ Engine Specifications Primary Engine Engine Code: EJ257 Engine Type: 2.5L DOHC turbocharged flat-four boxer engine Performance Horsepower Output: 300 hp @ 6000 rpm (approx.) Torque Output: 300 lb-ft @ 4000 rpm (approx.) Fuel System Fuel Delivery: Multi-point fuel injection (MPI) with top-feed injectors. Recommended Fuel: Premium Unleaded Gasoline (91 octane or higher) Cooling System Coolant Type: Subaru Super Coolant (Blue) or equivalent silicate-free OAT coolant. Lubrication Oil Type: Synthetic SAE 0W-30 or 5W-30 Oil Capacity: 4.8 US quarts (4.5 Liters) with filter Turbocharger Turbo Model: IHI VF39 (typical for this generation) 🔧 Transmission Standard Transmission Type: 6-speed Manual Transmission Optional Optional Transmission: N/A (STI models were exclusively manual) Features Dccd System: Driver Controlled Center Differential (DCCD) for adjustable torque split. Fluid Specifications Transmission Fluid Type: Subaru Extra Synchros 75W-90 GL-5 (gearbox) / Subaru Extra Synchros 75W-90 GL-5 (transfer/rear diff, though separate fill often specified). Clutch Fluid: DOT 3 or DOT 4 brake fluid 📐 Dimensions Exterior Length: 4415 mm (173.8 in) Width: 1770 mm (69.7 in) Height: 1440 mm (56.7 in) Wheelbase: 2625 mm (103.3 in) Weights Curb Weight: Approx. 1450-1500 kg (3197-3307 lbs) Gross Vehicle Weight Rating: Not typically specified in detail for performance models, but implied by chassis load capacity. Wheels And Tires Standard Wheel Size: 17 x 7.5 inches Standard Tire Size: 225/45R17 Bolt Pattern: 5x100 mm 🛡️ Safety Features Ratings NHTSA Front Impact Rating: 4/5 Stars (for comparable 2004 Impreza models, STI specific may vary slightly) IIHS Side Impact Rating: Good (for comparable 2004 Impreza models) Active Features ABS: Standard Anti-lock Braking System (ABS) Traction Control: Standard Traction Control System (TCS) and Vehicle Dynamics Control (VDC). Passive Features Airbags: Front airbags, side airbags, and curtain airbags (depending on specific market/trim). Seat Belts: 3-point seatbelts with pretensioners and force limiters. Chassis Design Body Structure: Reinforced unibody construction with crumple zones. 💡 Technology Features Infotainment Audio System: Factory AM/FM/CD player with optional premium audio. Display System: Basic digital/analog instrumentation, no advanced touchscreen infotainment. Driver Assistance Cruise Control: Standard electronic cruise control. Connectivity Usb Aux Input: Generally not equipped with factory USB/Aux inputs; aftermarket solutions common. 🔧 Maintenance Service Intervals Oil Change Interval: Every 3,000-5,000 miles or 3-6 months, especially under...