Workshop service equipment for Bosch products had been around since 1918. Bosch offered the first spark plug tester in 1927. And when new products were introduced, additional testing devices to test and service them were quick to follow. In 1938, Bosch sold the first test bench for diesel injection pumps - two years after the world's first series-production diesel car went on sale to the public. The product range was dominated largely by testers for individual components. As a result of the company's specialization in electrical components and fuel-injection equipment, Bosch offered numerous devices for various types of electrical equipment to garages, the workshops of Bosch sales outlets, and the Bosch services.

This was the advertising slogan that Bosch used to sell its new tester, the "EFAW 15," and its sister model to garages. The EFAW 15 was a small green metal suitcase that cost 540 German marks. The kit it included could test common electrical components such as spark plugs, ignition coils, generators, generator regulators, as well as ignition capacitors and suppressor capacitors. It also could be used to set the ignition timing, check charging rates, and test the circuit voltage.

Bosch advertised its new generation of equipment not only as tailor-made technology for garages, but also as an image enhancer for workshops: "Today's customers want to see first-class, efficient workshop equipment. This gives an automatic lead to workshops that are able to create a quick and reliable report on a customer's car with the help of concise and prestigious testing equipment." This promotional text from September 1955 recommends three ways to gain customer loyalty: professional, state-of-the-art equipment; prestigious, attractive, and first-class testing equipment; clearly structured equipment. The experts must be able to explain the functions of this equipment clearly to the customer, particularly when the test results show a certain part in the customer's car has to be replaced.

This emphasis on psychology is surprising, given the time and the profession. "Shed the grubby image!" could have been the motto. Rather than oily rags lying next to overflowing ashtrays, customers were supposed to associate the typical garage with neatly dressed mechanics who operated precise, silent equipment, and employed processes that even laypersons could understand.

Starting in 1963, Bosch offered its engine tester, which also could check carburetor functions and later fuel-injection equipment. All the while, the testing equipment had to keep pace with the company's increasingly sophisticated automotive technology to ensure that difficult test processes ran smoothly, including tests of engines' electronic control units. Even today, Bosch still has to come up with suitable solutions to this task. In the era of digital vehicle management and short lifecycles of product generations, this means consistently supplying garages with top-notch software for the latest electronic controls.