The Mazda3, introduced in 2003 as the first generation (BK), is a compact car celebrated for its sporty handling, stylish design, and driver-focused interior, embodying Mazda's Jinba Ittai philosophy. Available as a 4-door sedan or 5-door hatchback, it offered a choice between a 148 hp 2.0L inline-4 engine and a more powerful 160 hp 2.3L inline-4 engine, both featuring DOHC and Continuously Variable Valve Timing. This model, built on the Ford Global C1 Platform, received acclaim, including being named to Car and Driver's 10Best list for its initial model years, and consistently maintained strong resale value. Safety was a key consideration, with standard Anti-lock Braking System and Electronic Brakeforce Distribution, and optional airbags and stability control, contributing to its strong safety ratings. This comprehensive factory service manual provides extensive guidance for the maintenance, troubleshooting, and repair of the Mazda3 (BK). Covering all major systems, including powertrain, chassis, and electrical components, it details procedures from routine scheduled maintenance, such as oil and filter changes, to in-depth engine rebuilds and transmission overhauls. The manual includes diagnostic trouble code explanations, symptom-based troubleshooting guides, and detailed electrical schematics to assist owners, mechanics, and technicians in keeping the vehicle in optimal condition. With over 2000 pages of information, this English-language, text-searchable document offers the depth required for effective vehicle upkeep and repair.