Working with On-Board Diagnostics (OBD) Data for Engine Management Systems The Volkswagen Scan Tool Companion 1990-1995 is the essential reference book for the professional Volkswagen technician or the do-it-yourselfer with a Volkswagen scan tool. This book, together with a VAG 1551 scan tool or equivalent scan tool software, is the only equipment you'll need to interrogate and diagnose 1990 through 1995 Volkswagen engine management systems. You'll find all the engine management factory scan tool support information in one place culled from volumes of factory service information in an easy-to-use format. You'll also find lots of additional information not found in any factory repair manual, including nominal values for correctly functioning engine management systems, scan tool fundamentals, and exhaust and emissions theory. Coverage includes gasoline engine management systems with On Board Diagnostics (OBD) commonly referred to as OBD-I (systems without readiness codes) for 1990 through 1995 model year Golf, Jetta, GTI, Corrado, Passat, Fox, Cabriolet, and Eurovan including California and Canadian versions. Also covered is the 1995 Winnebago Rialta and Camper and the OBD-D system found on 1996 Passat TDI diesel.