Vehicle Segment:
Compact/Small Family Car, known for its all-wheel-drive capability and sporty variants.
Key Competitors:
Mitsubishi Lancer, Honda Civic, Toyota Corolla, Mazda3, Ford Focus.
Performance Variants:
The 2004 model year continued the legacy of performance with WRX and STI variants, known for their turbocharged engines and advanced AWD systems.
AWD Emphasis:
Subaru's Symmetrical All-Wheel Drive system is a hallmark, providing enhanced traction and handling in various conditions.
Diagnostic Value:
Essential for diagnosing and repairing complex electrical issues, reducing diagnostic time, and ensuring proper system function.
Diy Support:
Empowers DIY mechanics to tackle advanced electrical repairs and modifications with accurate schematic information.
Covered Systems:
Complete electrical system, including engine control, lighting, audio, climate control, safety systems, and body electronics.
Pages:
Estimated 200-300 pages (typical for this type of specialized manual)
Type:
Technical Service Manual Supplement (Wiring Diagrams)
Engine Management:
Detailed wiring for Engine Control Module (ECM), fuel injectors, ignition system, sensors (oxygen, MAP, MAF, coolant temp, crank/cam position), and actuators.
Powertrain Controls:
Wiring for transmission control module (if applicable), solenoids, and sensors related to powertrain operation.
Exterior Lighting:
Headlights (low/high beam), taillights, brake lights, turn signals, fog lights, license plate lights, and associated switches/relays.
Interior Lighting:
Dome lights, vanity lights, dashboard illumination, and instrument cluster lighting.
Stereo System:
Wiring for factory radio, speakers, antenna, and amplifier (if equipped).
HVAC System:
Wiring for blower motor, HVAC control panel, A/C compressor clutch, temperature sensors, and actuators.
Airbag System:
Wiring for SRS module, impact sensors, pretensioners, and warning lights.
Anti Theft Alarm:
Wiring for factory alarm system, immobilizer, and door lock actuators.
Power Accessories:
Wiring for power windows, power door locks, power mirrors, and sunroof (if equipped).
Wiper Washer:
Wiring for front and rear wipers, washer pump, and related switches.
Instrument Cluster:
Wiring for speedometer, tachometer, fuel gauge, temperature gauge, warning lights, and information displays.
Troubleshooting:
Guidance on diagnosing electrical faults using wiring diagrams, component testing procedures, and common failure points.
Component Identification:
Identification of electrical components, connectors, terminals, and wire colors.
Harness Routing:
Information on the routing and protection of wiring harnesses throughout the vehicle.
Depth:
Advanced diagnostics and repair, suitable for professional technicians and experienced DIYers. Includes detailed schematics, connector views, and component locations.
Engine Type:
Horizontally Opposed (Boxer) Engine
Displacement Liter:
2.5L (EJ25 SOHC/DOHC)
Horsepower Hp:
Standard models: 165-175 hp; WRX: 227 hp; STI: 300 hp (approximate, varies by specific model and market)
Torque Lb Ft:
Standard models: 166-170 lb-ft; WRX: 224 lb-ft; STI: 300 lb-ft (approximate)
Turbocharger:
Yes (standard on WRX and STI models)
Drivetrain:
Symmetrical All-Wheel Drive (AWD)
Fuel Delivery:
Multi-point Fuel Injection (MPI)
Fuel Type:
Unleaded gasoline (Premium Unleaded required for WRX/STI)
NHTSA Front Crash Driver:
5-Star (for applicable models/years)
NHTSA Front Crash Passenger:
5-Star (for applicable models/years)
IIHS Front Offset Score:
Good (for applicable models/years, check specific tests)
ABS:
Standard (Anti-lock Braking System)
Traction Control:
Available on some models, standard on WRX/STI.
Electronic Stability Control:
Not widely available or standard on this generation's common trims.
Airbags:
Front airbags, optional side airbags.
Seatbelts:
Three-point seatbelts with pretensioners for front seats.
Head Unit:
Factory AM/FM/CD player, often with cassette. Higher trims may offer premium audio systems.
Speaker Configuration:
Typically 4 or 6 speakers, with subwoofer option on higher trims.
Cruise Control:
Standard on most models.
Auxiliary Input:
Not standard; often added aftermarket.
OBD Ii:
Standard OBD-II diagnostic port for engine and emissions monitoring.
Oil Change:
Every 3,000-5,000 miles or 3-6 months, depending on driving conditions and oil type used.
Air Filter:
Replace every 15,000-30,000 miles or as needed.
Spark Plugs:
Replace every 30,000-60,000 miles (depending on plug type; iridium recommended).
Timing Belt:
Crucial: Replace every 105,000 miles or 7 years (interference engine). Includes idler pulleys and tensioner.
Engine Oil Type:
SAE 5W-30 or 10W-30 (check owner's manual for specific recommendations; synthetic recommended).
Engine Oil Capacity Quarts:
4.5 - 4.8 quarts (with filter, depends on engine variant)
Coolant Type:
Subaru Super Coolant or equivalent (blue colored)
Transmission Fluid Manual:
75W-90 GL-5 gear oil
Transmission Fluid Automatic:
Subaru ATF-HP or equivalent
Differential Fluid:
75W-90 GL-5 gear oil (front and rear)
Head Gaskets:
While less prevalent than on some earlier Subaru models, monitor for potential coolant leaks or milky oil, especially on EJ25 SOHC engines.
Turbo Wear:
On WRX/STI models, turbocharger health is critical. Regular oil changes and proper cool-down procedures are vital to prevent premature wear.
Clutch Wear:
Manual transmission clutches can wear out, especially with aggressive driving. Torque converter issues on automatics are also possible.
Electrical Gremlins:
Wiring issues, sensor failures, and module malfunctions are common areas where a wiring diagram manual is invaluable.
Subaru Legacy:
Subaru, known for its Subaru Automotive Industry Co., Ltd., has a long history of producing reliable vehicles with a focus on boxer engines and AWD.
Gc8 Gd Generation:
The 2004 Impreza belongs to the second generation (GD/GG), which debuted for the 2002 model year, featuring a significant styling update.
Wrx Sti Development:
The performance variants (WRX and STI) gained significant global recognition for their rally racing success.
Manufacturing Location:
Japan
