On the test bench, engineers investigate the behavior of assemblies such as engine, transmission or brake systems in great detail. For example, multichannel temperature measurements may facilitate the mapping of temperature profiles of the cylinder head. Final validation of assembly function is obtained by means of road tests. In the lab, electronics and software development engineers test the electronic system used to control the assembly before it is passed for subsequent testing. To optimize the behavior of a given assembly, calibration engineers adjust the parameters of control and diagnostic functions handled by the governing ECU. As regards engine management, engine performance, fuel consumption, and emission properties are considered. Calibration engineers need to look at the inner workings of the ECU and make online comparisons with external measurements or signals on the vehicle buses. To approach different working points and optimize the values of control parameters, the test bench is the ideal facility for the application of automated test routines.