The aim of this dissertation is to focus on the systems design of a multi purpose engine tester, a device for diagnostic techniques of self propelled motor vehicles to be used in a car mechanics work shop. The principle aim is to combine a permanently installed PC, a portable laptop and a workshop trolley containing all the necessary assembly tools and accessories. These three pieces used together will serve as a self contained unit within the workshop. I will compare the quality of the devices with others on the market. I will talk about the layout of the individual parts such as the design, structure and shape of the unit, as well as the ergonomics of the designed pieces. An important factor will be reducing the size of the device without compromising the quality and keeping it a similar price to other similar products on the market.