This manual covers the Audi/Volkswagen 1.8T engine family, a popular turbocharged inline-four cylinder engine that powered numerous models from the late 1990s through the mid-2000s, including various Audi A3, A4, TT, and Volkswagen Golf, Jetta, Passat, and New Beetle variants. Known for its performance and adaptability, the 1.8T engine, with designations such as AEB, APU, AWM, and BPG, offered between 150 to 180 horsepower and was recognized with awards like Ward's 10 Best Engines. This engine family features a DOHC, 20-valve aluminum alloy cylinder head and cast-iron block, utilizing electronic multi-port fuel injection and a turbocharger for enhanced power delivery. Its widespread use across popular platforms underscores its significance and the need for comprehensive technical information.

This troubleshooting guide compilation is designed to assist DIY enthusiasts, independent repair shops, and professional technicians in diagnosing and resolving common issues specific to the 1.8T engine. It delves into critical areas including engine mechanical components, engine electrical systems, fuel and ignition systems, emissions control, turbocharging, cooling, and lubrication. The manual provides detailed coverage of common fault codes, diagnostic procedures, and practical repair strategies, focusing on real-world problems such as misfires, boost control issues, and PCV system failures. With an estimated 150-250 pages of English-language content, this digital, text-searchable resource offers an intermediate to advanced level of technical detail, enabling effective maintenance and repair of this complex and widely used engine.