Engine Mechanical:
EJ255 (WRX), EJ257 (STI) - Disassembly, assembly, inspection, lubrication, cooling, fuel delivery, ignition, exhaust, emissions control
Engine Management:
ECU diagnosis, sensor operation, fuel injection strategy, ignition timing control, emissions controls (EVAP, secondary air injection)
Transmission:
TY756 (STI 6MT), TY856 (STI 6MT), CZ (WRX 5MT) - Operation, maintenance, repair, overhaul procedures, fluid specifications, differential maintenance
Drivetrain:
All-Wheel Drive (AWD) system, center differential, front and rear differentials, driveshafts, axles, hubs
Suspension:
Front MacPherson strut, rear double wishbone, sway bars, bushings, alignment specifications
Brakes:
Front Brembo (STI), Lucas (WRX) - Disc brakes, ABS system, brake fluid specifications, bleeding procedures, rotor and pad replacement
Steering:
Power assisted rack and pinion, steering column, pump, fluid specifications
Electrical System:
Battery, charging system, starter, lighting, horn, power windows, wipers, mirrors, power locks, fuses, relays, wiring diagrams
Climate Control:
HVAC system, A/C compressor, refrigerant R134a, heater core, blower motor, controls
Body Exterior:
Body panels, doors, hood, trunk, bumpers, glass, trim, rust prevention, corrosion control
Body Interior:
Seats, dashboard, door panels, headliner, carpeting, safety belts, airbags
Maintenance:
Oil changes, filter replacements, fluid checks and top-offs, spark plug replacement, air filter service, brake pad/rotor inspection and replacement, tire rotation, coolant flush
Troubleshooting:
Diagnostic trouble codes (DTCs), symptom-based troubleshooting guides, electrical diagnostics, mechanical issues
Repair:
Engine component replacement (pistons, connecting rods, camshafts), transmission rebuild, clutch replacement, brake caliper overhaul, strut replacement, exhaust system repair, body panel repair, electrical component replacement
Diagnostics:
OBD-II scanning, sensor testing, actuator testing, pressure testing (fuel, oil, coolant), compression testing
Technical Specifications:
Torque specifications for all fasteners, clearances, tolerances, fluid capacities, electrical specifications
Depth:
Comprehensive: Covers everything from basic maintenance to complete engine and transmission overhauls, including detailed electrical troubleshooting and body repair. Suitable for professional mechanics and advanced DIY enthusiasts.
NHTSA Front Impact:
5-Star (Driver), 4-Star (Passenger) for sedan models
IIHS Small Overlap Front:
Not Rated (typical for this era and model)
ABS:
Standard on all models
Traction Control:
Standard on STI, optional/unavailable on some WRX trims
Electronic Stability Control:
Standard on STI, optional/unavailable on some WRX trims
Airbags:
Frontal airbags, front side-impact airbags (standard on STI, optional/standard on WRX depending on trim)
Seatbelts:
3-point front and rear seatbelts, pretensioners, force limiters
Oil Change Interval:
Every 3,750 miles or 6 months (severe conditions) or 7,500 miles or 12 months (normal conditions) - refer to FSM for exact Subaru recommendations.
Transmission Fluid Change:
Every 30,000 - 60,000 miles (depends on driving conditions, refer to FSM)
Coolant Flush:
Every 30,000 miles or 2 years (using Subaru Super Coolant)
Spark Plug Replacement:
60,000 miles (Iridium)
Engine Oil:
SAE 0W-30 Synthetic (API SN or higher recommended), capacity 4.8 US quarts (4.5 L) with filter
Sti Manual Transmission Fluid:
Subaru Extra-S Gear Oil 75W-90 (or equivalent GL-5 rated)
Wrx Manual Transmission Fluid:
Subaru Genuine Gear Oil API GL-5 75W-90
Brake Fluid:
DOT 3 or DOT 4
Coolant:
Subaru Super Coolant (Blue) - 50/50 mix with distilled water
Engine Ring Land Failure:
Common on EJ255/EJ257 engines, particularly with aggressive tuning or detonation. Manual details diagnosis and repair.
Clutch Wear:
Can be accelerated by aggressive driving, especially in STI models. Manual covers replacement and diagnosis.
Turbocharger Issues:
Potential for wear or failure if oil starvation or contamination occurs. Manual provides inspection and maintenance guidance.
Differential Issues:
Rear differential seal leaks or viscous coupling issues in AWD system. Manual covers inspection and repair.
