Book excerpt: Microsystems applications (MST) in automobiles have become commonplace: they enable the introduction of a series of new functions and at the same time the replacement of existing technologies offering improved performance and better value for money. Microsystems are indispensable for fulfilling a complete transition from the mechanically driven automobile system to a mechanically based but ICT-driven system as part of a likewise complex environment. With the introduction of micro-systems a series of challenges arise regarding complexity, systems design, reliability, serviceability, etc. These challenges have to be addressed in order to meet high customer expectations concerning performance and price.