Firstly show you how to connect all parts:
1)Connect ECU Cable-B to Key Tool Plus
2)Connect ECU Cable-B to BOSH Adapter
3)Supply 12 volts power to BOSH Adapter
4)Connect ECU Cable-A to N20 computer by diagrams.
5)Finally connect ECU Cable-A to BOSH ECU Adapter
Prog>>Read ECU with CAN>>BMW>>MEVD17.2.4_Fxx(N20)
Read and save data.