The networking of control devices is well advanced in a modern automobile. To ensure secure communications with each other and to prevent mistakes due to communication error, protocol tests are performed at the physical and data link layer level. In a modern car the diagnosis of the electronic devices (e.g. reading/deleting fault memory entries) is done with a standardized communication protocol (UDS - Unified Diagnostic Services). Modern control units have this diagnostic capabilities to detect this communication error among others. This data is provided for a guided troubleshooting the vehicle via a defined interface. In this communication test detection mechanisms are specifically stimulated and read afterwards. In order to read or delete these entries, a diagnosis query is performed on the basis of the diagnostic protocol UDS. The diagnostic requests are currently performed with a diagnostic service of bus analysis software Vector CANoe. This service requests can be performed directly on CAN but for the diagnosis of other bus systems a software gateway is used. The maintenance required and the error rate of the software gateways is very high and should be replaced in the future. Furthermore, additional bus systems can be integrated only with great effort. Therfore the main aim of the master thesis was to develop a concept for univesal UDS API and afterwards implementation of that concept using CAPL programming for modular use in test environments for vehicle communication testing.