The Porsche 928 S, specifically the Model 90 variant, represents a pinnacle of German engineering from the late 1980s to early 1990s. As a luxury grand tourer, it distinguished itself with a front-engine, rear-wheel-drive V8 configuration and a rear transaxle, achieving an ideal 50/50 weight distribution. This powerful vehicle, powered by a 4.7 or 5.0-liter V8 engine, offered sophisticated performance and advanced technology for its era, competing with esteemed marques like Ferrari and Mercedes-Benz. Its design and engineering were recognized for excellence, notably winning European Car of the Year in 1978, setting a high standard for automotive innovation and driver experience.

This manual provides comprehensive guidance focused on the electrical system of the Porsche 928 S, Model 90. It covers essential areas such as electrical system troubleshooting, detailed wiring diagrams, component identification, and the functionality of electrical components. The manual is designed to assist both experienced DIY enthusiasts and professional automotive technicians in diagnosing and repairing complex electrical issues, including powertrain, chassis, comfort, and safety systems. By offering step-by-step fault diagnosis, repair procedures, and component testing methods, this English-language resource empowers users to maintain and restore the vehicle's intricate electrical network efficiently.