The real book is a practical manual on diagnostics of electronic control system by petrol and diesel engines. The serial, most popular models of cars of foreign producers of 1995-2004 of producing are examined in a book.Basic principles of construction are described in a book, functional features of construction of electronic control system by an engine (ЭСУД). Offered an author intuitively clear and logical methodology of diagnostics of components of control system by an engine. The receipts over and interpretations of information of the system of self-diagnose of cars given about an order are brought.A book is intended for specialists, professionally engaging in repair cars, and also for the ordinary motor-car enthusiasts, interested in the device of electrical equipment of the car.