On E38 and E39/E53 High version veh

On E38 and E39/E53 High version vehicles:The LCM is the Master Controller of the I-bus. The lKE and MID/BMBT are Stand-byThe gm is the master Controller of the k-biOn E46 E52 and E39/E53 Base version vehicles:The GM is the Master Controller for vehicles equipped with only the K-busThe LCM/LSZ is the Stand-by ControllerFailure of the Bus cableThe following faults can occur to the i/K bus wiringShort Circuit to b+Short circuit to b-Bus line down(open)Defective plug connections(damaged, corroded, or improperly crimpedShort Circuit to B+: Modules that send a message see that the message was notreceived and that the bus remains high. However, subscribers are unable to decidewhether the fault is due to a shorted line or a defect in the communication interface, The module will repeat its message 5 times before discontinuing and faulting. The module willcontinue to operate as normal minus any commands that could not be delivered by thebusShort Circuit to B-: The subscribers do not interpret a low bus line as a fault but just asa bus line deactivation. The Master and Standby controllers do detect the short and enter it as a bus fault. (No communicationBus Line Down: The bus line may be open at any of several locations. As long as the Master or Stand-by is still connected, communication can occur with any modules stillmaining. The fault situation will be the same as if the disconnected modules were defective themselvesChecking the bus line is carried out just like any other wiring. Perform continuity tests between the connections of different modules (all modules disconnected without forgettingto make sure that the bus has not shorted to ground or another wire. It is recommended to use the " Wire Test"in "Preset Measurements"which is more sensitive than just a resistance check