The C-Class, codenamed W203, represents the compact executive luxury segment, known for its elegant styling, refined interior, and a strong emphasis on safety and comfort. Produced from 2001 to 2007, this generation offered a range of efficient and powerful gasoline and diesel engines, including supercharged variants, paired with either manual or automatic transmissions. The C-Class was designed to be a competitive and modern vehicle, building upon a legacy of engineering excellence and longevity. Its sophisticated design philosophy, coupled with innovative technologies like advanced safety systems and climate control, made it a popular choice for individuals seeking premium quality and performance in a compact luxury package. This comprehensive workshop service and repair manual provides detailed information for the diagnosis, repair, and maintenance of the C-Class (W203) models from 2001 to 2007. It covers all gasoline and diesel engine variants, automatic and manual transmissions, and sedan, coupe, and wagon body styles. The manual includes extensive coverage of engine mechanicals, fuel and ignition systems, brakes, suspension, steering, and the complete electrical system, along with detailed procedures for routine maintenance, component removal and installation, troubleshooting, and rebuilds. This resource is invaluable for owners, mechanics, and technicians aiming to maintain and repair the vehicle with accuracy and efficiency. 🏷️ Basic Information Identification Make: Mercedes-Benz Model: C-Class Generation Codename: W203 Model Years Covered By Manual: 2001, 2002, 2003, 2004, 2005, 2006, 2007 👋 Introduction Market Position Segment: Compact Executive / Entry-Level Luxury Target Audience: Individuals seeking premium quality, comfort, and performance in a compact luxury vehicle Competitive Analysis Key Competitors: BMW 3 Series (E46), Audi A4 (B6), Lexus IS, Volvo S60 Key Features Of Vehicle Design Philosophy: Elegant styling, refined interior, strong emphasis on safety and comfort Powertrain Options: Range of efficient and powerful inline-4 and V6 gasoline engines, and common-rail diesel engines Innovative Technologies: Advanced safety systems (e.g., ESP, PRE-SAFE availability), sophisticated climate control 📋 Manual Details Coverage Areas Comprehensive Coverage: Yes Engine Coverage: All gasoline and diesel variants for the specified years Transmission Coverage: Automatic and Manual transmissions Body Style Coverage: Sedan, Coupe, and Wagon (T-Model) Page Count Estimated Page Count: Extensive (typically 2000+ pages for a complete workshop manual) Manual Type Type: Complete Workshop Service and Repair Manual Purpose: Diagnosis, repair, maintenance, and overhaul procedures Language Language: English Format Format: Downloadable Digital Format (typically PDF) 📖 Manual Coverage Systems Covered Engine Mechanical: Engine assembly, cylinder head, pistons, crankshaft, camshafts, timing, lubrication, cooling Engine Management: Fuel injection, ignition system, electronic control unit (ECU), sensors, emission control Transmission Mechanical: Automatic transmission (e.g., 722.6 '5G-TRONIC') overhaul, manual transmission overhaul, clutch Transmission Electronic: Transmission control module (TCM) diagnostics, shifting solenoids, mechatronics unit Brakes: Hydraulic system, ABS, ESP (Electronic Stability Program), brake pads, rotors, calipers, parking brake Suspension: Front and rear suspension components, shock absorbers, springs, bushings, alignment Steering: Power steering system, steering rack, steering column, tie rod ends Electrical System Overview: 12V battery, alternator, starter, wiring diagrams, fuses, relays Body Electrical: Lighting, wipers, power windows, door locks, mirrors, seats, interior trim Climate Control: HVAC system, A/C compressor, refrigerant, heater core, climate control module Infotainment Audio: COMAND system, Audio 20, speaker systems, antenna module (coverage may vary) Safety Systems: Airbags (SRS), seatbelt pretensioners, crash sensors Procedures Included Routine Maintenance: Oil changes, filter replacements, spark plug replacement, fluid checks and top-offs Component Removal Installation: Engine, transmission, suspension components, brake assemblies, body panels, interior components Troubleshooting Diagnostics: Diagnostic trouble codes (DTCs), symptom-based troubleshooting guides, electrical testing procedures Rebuild Procedures: Engine and transmission overhaul procedures, detailed step-by-step instructions Electrical Diagnostics: Wiring diagrams interpretation, component testing, signal tracing Bodywork Repair: Panel replacement, dent repair, rust prevention (general guidelines) Specifications Data: Torque specifications, clearances, fluid capacities, electrical parameters Technical Depth Depth: Comprehensive, from basic maintenance to complete engine and transmission rebuilds Diagnostic Tools: Information to guide the use of Mercedes-Benz diagnostic tools (e.g., STAR Diagnosis) 📊 Manual Specifications File Format Format: PDF Searchability: Fully searchable text content Printability: Printable pages for ease of use in a workshop environment Print Quality Image Resolution: High-resolution diagrams and illustrations Binding Type Binding: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Codes Examples: M271 (1.8L/2.0L Supercharged I4), M111 (2.0L Supercharged I4), M112 (2.6L/3.2L V6), OM611 (2.1L Diesel I4), OM646 (2.1L Diesel I4) Performance Horsepower Range: Approx. 120 HP (C200 CDI) to 272 HP (C350) Torque Range: Approx. 200 Nm (C200 CDI) to 350 Nm (C320 CDI) Fuel System Fuel Delivery Gasoline: Electronic Fuel Injection (EFI) / Sequential Multipoint Fuel Injection (SMPI) Fuel Delivery Diesel: Common Rail Direct Injection (CDI) Engine Features Supercharging: Availability of supercharged engines (e.g., M271 Kompressor) Valvetrain: DOHC (Double Overhead Camshafts), 4 valves per cylinder Emission Control: Catalytic converters, EGR (Exhaust Gas Recirculation) for diesel models 🔧 Transmission Standard Standard Transmission Type: 5-speed or 6-speed Manual Transmission (RWD) Optional Optional Transmission Type: 5-speed or 7-speed Automatic...