Since most of the sensors and systems in the BMW 3 Series are connected by the system data bus, the dashboard is the information center. System bus "K-bus" connects exterior and interior lighting, rain sensor, air conditioning/heating system and vehicle electrical system. System bus "CAN-bus" connects the engine management system, the transmission management system, and the ABS/traction control/dynamic stabilization system. System bus "D-bus" connected to the diagnostic socket of the system and to the diagnostic socket according to the European standard (EODB).
The speedometer shows the vehicle speed obtained from the ABS readings from the rear left wheel sensor.
At the time of writing this manual, data on the possibility of replacing individual components of the dashboard was not available, that is, the dashboard should be replaced as a single sealed unit. If a malfunction occurs in any of the components of the dashboard, remove the dashboard (see paragraph 9) and have it checked by a BMW dealer. For this purpose, BMW has a special tester, which allows you to detect a faulty component, as well as to make the best decision for troubleshooting.