Nowadays almost all vehicle functions are related to electronic control units. ECUs are linked with each other via a bus system (CAN-Bus). Various inputs are converted via sensors into electrical output signals which allow the control unit to regulate different functions.
The large number of ECUs in a vehicle depends on the model and configuration level. Whereas in the past only 1-2 electronic control units, e.g. ignition control, were available, today there are 50 or more different control units which have to regulate their partial functions and communicate with each other.
Engine control and transmission control management, electronic control of braking systems (ABS, ESP, ASR), central electronics and body control modules, instrument cluster and airbags, control of special functions for diesel pump, roof control and cruise control units, air control units, electronic door and window control, central locking, seat control devices, electronic steering, light or xenon control modules, navigation systems, other driver assistance systems and more.
Large manufacturers such as Bosch, Siemens, VDO, Mitsubishi Electric and Denso produce almost all controller types, while others have focused controllers for certain functions.
last update: 22.2.2019