Segment:
Compact Executive Sedan/Coupe/Wagon
Positioning:
Premium compact luxury vehicle offering refined comfort, advanced technology, and strong brand prestige.
Key Competitors:
BMW 3 Series (E46), Audi A4 (B6), Lexus IS300, Infiniti G35
Design:
Modern, flowing lines with signature Mercedes-Benz grille and interior quality.
Performance:
Responsive engines, refined handling, and comfortable ride quality.
Technology:
Introduction of advanced features like COMAND infotainment and advanced safety systems.
Engine Mechanical:
Complete overhaul, timing, lubrication, cooling, fuel delivery, emissions control
Engine Management:
ECU diagnostics, sensor data, ignition system, fuel injection control
Transmission Manual:
Clutch, gear selection, overhaul, fluid service
Transmission Automatic:
Control module diagnostics, valve body, torque converter, fluid service, overhaul
Drivetrain:
Drive shafts, CV joints, differential, axles
Suspension:
Front and rear suspension components, alignment, shock absorbers, springs, bushings
Steering:
Power steering system, steering rack, tie rods, steering column
Brakes:
ABS, ESP, brake discs, pads, calipers, lines, master cylinder, bleeding procedures
Electrical System:
Battery, alternator, starter, wiring diagrams, fuse boxes, relays
Lighting:
Headlights, taillights, interior lighting, bulb replacement, aiming
HVAC:
Air conditioning system, heater core, blower motor, climate control module, refrigerant servicing
Body Interior:
Door panels, seats, dashboard, trim, headliner, glass replacement
Body Exterior:
Bumpers, fenders, hood, trunk lid, doors, body panel alignment, rust repair
Infotainment:
Audio system, navigation, display unit, control modules
Comfort Systems:
Power windows, power locks, power mirrors, keyless entry, sunroof operation
Maintenance:
Scheduled maintenance, oil changes, filter replacements, fluid checks and top-offs
Diagnostics:
Troubleshooting guides, fault codes (DTCs), diagnostic procedures for all systems
Repair:
Step-by-step repair instructions for all major components and systems
Rebuilds:
Engine and transmission overhaul procedures, component-specific rebuilds
Adjustments:
Alignment adjustments, electronic system calibrations, clutch adjustments
Electrical Repairs:
Component replacement, wiring harness repair, circuit troubleshooting
Body Repairs:
Panel replacement, dent repair, glass installation, sealing procedures
Depth:
Comprehensive; from basic maintenance to complete engine/transmission rebuilds and advanced electronic diagnostics
Detail Level:
Factory-level detail with specific torque specifications, clearances, and diagnostic procedures
Audience:
Professional technicians and advanced DIY enthusiasts
Engine Options:
M271 (1.8L Supercharged I4), M111 (2.0L Supercharged I4), M271 (2.0L Turbocharged I4), M112 (2.6L V6), M112 (3.2L V6), M113 (5.4L V8 - C32/C55 AMG)
Engine Displacements:
1.8L, 2.0L, 2.6L, 3.2L, 5.4L
Horsepower Range:
140 hp - 369 hp (depending on engine)
Torque Range:
140 lb-ft - 376 lb-ft (depending on engine)
Fuel Type:
Premium Unleaded Gasoline (91 RON or higher recommended)
Injection System:
Sequential Multi-Port Fuel Injection (MPI) or Direct Injection (DI) for some later variants not typically in 2004
M271 Evo:
Commonly found 1.8L (271.940, 271.942) and 2.0L (271.860, 271.941) variants with variable valve timing and supercharging/turbocharging.
M112 V6:
Robust 2.6L (112.910) and 3.2L (112.912, 112.916) SOHC V6 engines known for smoothness.
NHTSA Front Impact:
5-Star (for driver and front passenger)
IIHS Frontal Offset:
Good (for early W203 models, later updates improved structure)
Euroncap Overall:
4-Star (for 2002 models, likely similar for 2004)
Stability Control:
Standard ESP (Electronic Stability Program) on most models.
Braking System:
ABS (Anti-lock Braking System), Brake Assist (BAS)
Airbags:
Front airbags, side airbags, optional curtain airbags.
Seatbelts:
Pretensioners and force limiters on front seats, ISOFIX child seat anchors.
Body Structure:
High-strength steel safety cell with crumple zones.
Infotainment System:
COMAND (Cockpit Management and Navigation) system available on higher trims, featuring CD player, radio, navigation, and optional phone integration.
Instrument Cluster:
Clear, multi-function display providing vehicle status, trip computer, and diagnostic information.
Cruise Control:
Standard cruise control, optional DISTRONIC adaptive cruise control on some models.
Parking Sensors:
Optional Parktronic parking assist system (front and rear).
Phone Integration:
Optional Bluetooth phone preparation with cradle or integrated system.
Oil Change Interval:
Typically 15,000 km (9,300 miles) or 12 months, whichever comes first, with synthetic oil. Varies with driving conditions and oil type used.
Major Service:
Major services (e.g., spark plug replacement, transmission fluid change) recommended at higher mileages, often around 60,000-100,000 km (37,000-62,000 miles) depending on specific components.
Engine Oil:
MB 229.5 (e.g., Mobil 1 0W-40, Castrol EDGE 0W-40) is commonly recommended for gasoline engines. Always verify for specific engine. Capacity approx. 5.5-8.5L depending on engine.
Coolant:
MB 325.0 (Antifreeze/Coolant, ethylene glycol-based) or MB 326.0 (Pre-diluted) - typically a pinkish-red color. Capacity approx. 8-9L.
Brake Fluid:
DOT 4 PLUS (MB 331.0 specification)
M271 Timing Chain:
Potential stretching of the timing chain and wear on the tensioner and guides, leading to timing issues and noise. Early warning signs can include rattle on startup.
Oil Cooler Seals:
Leaking oil cooler seals, especially on the M112/M113 V6/V8 engines, can cause coolant contamination.
Evap Canister Purge Valve:
Faulty EVAP purge valve can lead to check engine lights and rough idling, particularly on M271 engines.
Window Regulators:
Plastic components in window regulators can degrade, leading to windows falling down inside the door.
Suspension Bushings:
Wear and tear on control arm bushings, especially front lower control arms, can cause clunks and affect alignment.
Mass Airflow Sensor Maf:
Can become dirty or fail, leading to poor engine performance and check engine lights.
Brand:
Mercedes-Benz: Renowned for engineering excellence, luxury, and safety innovations since the early 20th century.
W203 Generation:
Second generation of the C-Class, replacing the W202. Introduced in 2000.
Facelift:
The 2004 model year typically corresponds to the pre-facelift W203 (introduced 2000-2003). A significant facelift occurred for the 2005 model year, with styling and feature updates.
Production Years W203:
2000 - 2007
Manufacturing Locations:
Germany (Sindelfingen, Bremen), South Africa, Malaysia, Egypt, Thailand.