Testing embedded software systems on the control units of vehicles is a safety-relevant task, and developing the test suites for performing the tests on test benches is time-consuming. We present the foundations and results of a case study to automate the generation of tests for control software of vehicle control units based on a specification of requirements in terms of finite state machines. This case study builds upon our previous work on generation of tests for physical systems based on relational behavior models. In order to apply the respective algorithms, the finite state machine representation is transformed into a relational model. We present the transformation, the application of the test generation algorithm to a real example, and discuss the results and some specific challenges regarding software testing.