The 2005 BMW 3 Series, designated by the E90 chassis for the Sedan and E91 for the Wagon/Touring, represents a significant evolution in BMW's compact executive and sports sedan segment. Building on BMW's legacy of engineering excellence and the "Ultimate Driving Machine" ethos, this generation introduced notable advancements in engine technology, including Valvetronic and Double VANOS on its inline-6 cylinder engines (N52 series), alongside improved chassis dynamics and modern interior design. The 3 Series has consistently been recognized for its performance and handling, often earning accolades such as Car and Driver's 10Best awards, positioning it as a benchmark against competitors like the Audi A4 and Mercedes-Benz C-Class.

This comprehensive service repair manual provides in-depth technical information for maintaining, diagnosing, and repairing the 2005 BMW 3 Series Sedan (E90) and Wagon/Touring (E91). Covering a wide array of systems including powertrain, chassis, and electrical components, it details routine maintenance procedures, complex repair and rebuild tasks, troubleshooting guidance, and essential technical specifications and tolerances. With over 1000 pages of detailed, step-by-step instructions, illustrations, and diagrams, this manual is an indispensable resource for owners, mechanics, and technicians aiming to ensure the optimal performance and longevity of their vehicle.