🏷️ Basic Information

Make:

Subaru

Model:

Legacy

Year:

2004

Chassis Code:

BP (Wagon), BL (Sedan)

👋 Introduction

Segment:

Mid-size sedan and wagon, known for its standard All-Wheel Drive (AWD) and practical nature.

Competitors:

Toyota Camry, Honda Accord, Mazda6, Nissan Altima.

AWD Standard:

Standard Symmetrical All-Wheel Drive system across all trims, a significant differentiator.

Body Styles:

Available as a four-door sedan and a five-door wagon.

Target Audience:

DIY mechanics, independent repair shops, and Subaru owners looking to perform their own maintenance and repairs.

📋 Manual Details

General Coverage:

Complete factory service and repair information for the 2004 Subaru Legacy.

Specific Systems:

Engine mechanical, engine performance, fuel system, emissions control, transmission, drivetrain, suspension, steering, brakes, body, chassis electrical, HVAC, and diagnostics.

Estimated Pages:

1500+

Type:

Factory Service Manual / Workshop Manual

Language:

English

Format:

Digital (likely PDF)

📖 Manual Coverage

Engine:

2.5L EJ25 SOHC and DOHC naturally aspirated and turbocharged variants, timing belt service, head gasket repair, cooling system, lubrication system.

Transmission:

5-speed manual transmission (TY757 series), 4-speed automatic transmission (4EAT, TZ1A series), clutch replacement, transmission fluid service, differential service.

Drivetrain:

All-Wheel Drive (AWD) system operation, front and rear differentials, driveshafts, CV joints, wheel bearing replacement.

Suspension:

Front MacPherson strut, rear multi-link independent suspension, shock absorber replacement, spring replacement, control arm service, sway bar adjustment.

Steering:

Power steering system diagnosis and repair, steering rack replacement, tie rod end service, steering angle sensor calibration.

Brakes:

Front and rear disc brakes, ABS system diagnosis and repair, brake fluid flush, caliper and rotor replacement, parking brake adjustment.

Electrical:

ECU and sensor diagnostics, wiring diagrams, charging system (alternator, battery), starting system, lighting systems, power windows, central locking, airbag system.

HVAC:

Air conditioning system (refrigerant types, service procedures), heater core replacement, blower motor, climate control unit diagnostics.

Maintenance:

Oil and filter change, air filter replacement, cabin air filter replacement, spark plug replacement, fuel filter replacement, coolant flush, brake fluid change, transmission fluid change, differential fluid change.

Diagnostics:

OBD-II trouble codes (DTCs), sensor testing, actuator testing, wiring harness continuity checks, common fault diagnosis.

Repair:

Engine rebuild, head gasket replacement, timing belt replacement, turbocharger repair/replacement (turbo models), transmission overhaul, suspension component replacement, brake system overhaul, body panel repair.

Troubleshooting:

Step-by-step diagnostic flowcharts for common drivability issues, electrical problems, and mechanical failures.

Specifications:

Torque specifications for all critical fasteners, engine clearances, fluid capacities, electrical component resistance values.

Depth:

Comprehensive, covering everything from basic maintenance to complete engine and transmission rebuilds. Suitable for DIY enthusiasts and professional mechanics.

📊 Manual Specifications

Quality:

High-resolution scans, searchable text for ease of navigation, clear and legible diagrams.

Diagrams:

Top quality diagrams, illustrations, and schematics are a key feature.

Binding:

N/A (Digital Format)

Paper Quality:

N/A (Digital Format)

⚙️ Engine Specifications

Engine Code 1:

EJ253

Engine Type 1:

2.5L SOHC Naturally Aspirated Flat-4 Boxer

Displacement 1:

2457 cc

Horsepower 1:

165 hp @ 5600 rpm

Torque 1:

166 lb-ft @ 3600 rpm

Engine Code 2:

EJ255 (GT models)

Engine Type 2:

2.5L DOHC Turbocharged Flat-4 Boxer

Displacement 2:

2457 cc

Horsepower 2:

210 hp @ 5600 rpm

Torque 2:

236 lb-ft @ 3600 rpm

Injection:

Electronic Fuel Injection (EFI)

Fuel Type:

Unleaded gasoline

Timing Belt Replacement Interval:

105,000 miles or 105 months (whichever comes first) - Crucial for Boxer engines.

Spark Plug Type:

Iridium type, e.g., NGK IFR6A-11 or equivalent

Oil Type Recommendation:

SAE 5W-30 Synthetic or Synthetic Blend (API SN or higher)

🔧 Transmission

Transmission Type Standard:

5-speed manual transmission (TY757 series)

Transmission Type Optional:

4-speed automatic transmission (4EAT / TZ1A series)

AWD Operation:

Variable torque distribution, viscous coupling center differential (manual), planetary gear center differential with electronically controlled clutch pack (automatic).

Manual Transmission Fluid Spec:

GL-5 75W-90 Gear Oil (refer to manual for exact fill level and quantity)

Automatic Transmission Fluid Spec:

Subaru ATF HP (or equivalent Dexron III/Mercon compatible fluid, verify in manual)

📐 Dimensions

Sedan Length:

Approx. 187.4 inches

Wagon Length:

Approx. 187.6 inches

Width:

Approx. 68.1 inches

Height:

Approx. 56.1 inches (Sedan), 57.7 inches (Wagon)

Curb Weight Start:

Approx. 3200 lbs

Curb Weight End:

Approx. 3500 lbs (depending on trim and drivetrain)

Sedan Trunk Volume:

Approx. 14.7 cubic feet

Wagon Cargo Volume Seats Up:

Approx. 33.5 cubic feet

Wagon Cargo Volume Seats Down:

Approx. 65.4 cubic feet

Wheel Bolt Pattern:

5x100

Standard Tire Size:

205/50R17 or 215/45R17 (varies by trim)

🛡️ Safety Features

NHTSA Front Impact:

5 Stars (Driver and Passenger)

NHTSA Side Impact:

5 Stars (Front and Rear Passengers)

IIHS Front Crash:

Good

IIHS Side Impact:

Good

ABS:

Standard Anti-lock Braking System (ABS)

Traction Control:

Available Traction Control System (TCS)

Airbags:

Dual-stage front airbags, front side-impact airbags, front and rear side-curtain airbags (optional on some trims).

Seatbelts:

3-point seatbelts with pretensioners for all seating positions.

💡 Technology Features

Head Unit:

Factory single-CD player with optional AM/FM stereo, and optional premium audio system (e.g., Kenwood).

Connectivity:

Limited by modern standards. May include auxiliary input on some premium units. No Bluetooth or USB connectivity from the factory.

Cruise Control:

Standard electronic cruise control.

System Type:

Manual or optional automatic climate control.

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles or 6 months (severe service), 7,500 miles or 12 months (normal service) - Check manual for exact recommendation.

Brake Fluid Change Interval:

Every 30,000 miles or 24 months.

Coolant Change Interval:

Initial change at 30,000 miles or 24 months, then every 30,000 miles or 24 months thereafter. Use Subaru Super Coolant.

Engine Oil Capacity:

Approx. 4.8 quarts (4.5 liters) with filter for 2.5L SOHC, 5.1 quarts (4.8 liters) for 2.5L DOHC Turbo (verify in manual).

Coolant Type:

Subaru Super Coolant (Blue)

Head Gaskets:

While the EJ253 SOHC engine is generally less prone to head gasket failure than earlier DOHC versions, it's still a known area of concern for Subaru boxer engines of this era. Early detection and proper repair are vital.

Timing Belt Tensioner:

Failure of the timing belt tensioner can lead to belt slippage or breakage, causing significant engine damage. Regular inspection and replacement as per schedule is crucial.

Catalytic Converter:

Can become clogged over time, affecting performance and emissions. Diagnosis involves checking for codes and backpressure.

Wheel Bearings:

Can wear out prematurely, especially in areas with heavy use of road salt. Diagnosis involves listening for humming or grinding noises.

📚 Vehicle History

Subaru Core Values:

Focus on All-Wheel Drive technology, boxer engines, and reliability.

Third Generation:

This 2004 model is part of the third generation (2004-2009) of the Subaru Legacy, which introduced a more modern design and improved chassis.

Manufacturing Location:

Gunma Plant, Japan

🏆 Awards & Recognition

IIHS Top Safety Pick:

The 2004 Legacy often received good safety ratings, contributing to Subaru's reputation for safety.

Emisiones Compliance:

Meets ULEV (Ultra Low Emission Vehicle) standards in California and other compliant states.